With the maturation and advancement of blockchain technology,a novel execute-order-validate(EOV)architecture has been proposed,allowing transactions to be executed in parallel during the execution phase.However,parall...With the maturation and advancement of blockchain technology,a novel execute-order-validate(EOV)architecture has been proposed,allowing transactions to be executed in parallel during the execution phase.However,parallel execution may lead to multi-version concurrency control(MVCC)conflicts during the validation phase,resulting in transaction invalidation.Based on different causes,we categorize conflicts in the EOV blockchain into two types:within-block conflicts and cross-block conflicts,and propose an optimization solution called FabricMan based on Fabric v2.4.For within-block conflicts,a reordering algorithm is designed to improve the transaction success rate and parallel validation is implemented based on the transaction conflict graph.We also merge transfer transactions to prevent triggering multiple version checks.For cross-block conflicts,a cache-based version validation mechanism is implemented to detect and terminate invalid transactions in advance.Experimental comparisons are conducted between FabricMan and two other systems,Fabric and Fabric++.The results show that FabricMan outperforms the other two systems in terms of throughput,transaction abort rate,algorithm execution time,and other experimental metrics.展开更多
Although a number of methods are available for evaluating Linezolid and its possible impurities, a common method for separation if its potential impurities, degradants and enantiomer in a single method with good effic...Although a number of methods are available for evaluating Linezolid and its possible impurities, a common method for separation if its potential impurities, degradants and enantiomer in a single method with good efficiency remain unavailable. With the objective of developing an advanced method with shorter runtimes, a simple, precise, accurate stability-indicating LC method was developed for the determination of purity of Linezolid drug substance and drug products in bulk samples and pharmaceutical dosage forms in the presence of its impurities and degradation products. This method is capable of separating all the related substances of Linezolid along with the chiral impurity. This method can also be used for the estimation of assay of Linezolid in drug substance as well as in drug product. The method was developed using Chiralpak IA (250 mm 4.6 mm, 5 mm) column. A mixture of acetonitrile, ethanol, n-butyl amine and trifluoro acetic acid in 96:4:0.10:0.16 (v/v/v/v) ratio was used as a mobile phase. The eluted compounds were monitored at 254 nm. Linezolid was subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal and photolytic degradation. The degradation products were well resolved from main peak and its impurities, proving the stability-indicating power of the method. The developed method was validated as per International Conference on Harmonization (ICH) guidelines with respect to specificity, limit of detection, limit of quantification, precision, linearity, accuracy, robustness and system suitability.展开更多
The spikelet number per spike(SNS)contributes greatly to grain yield in wheat.Identifying various genes that control wheat SNS is vital for yield improvement.This study used a recombinant inbred line population genoty...The spikelet number per spike(SNS)contributes greatly to grain yield in wheat.Identifying various genes that control wheat SNS is vital for yield improvement.This study used a recombinant inbred line population genotyped by the Wheat55K single-nucleotide polymorphism array to identify two major and stably expressed quantitative trait loci(QTLs)for SNS.One of them(QSns.sau-2SY-2D.1)was reported previously,while the other(QSns.sau-2SY-7A)was newly detected and further analyzed in this study.QSns.sau-2SY-7A had a high LOD value ranging from 4.46 to 16.00 and explained 10.21-40.78%of the phenotypic variances.QSns.sau-2SY-7A was flanked by the markers AX-110518554 and AX-110094527 in a 4.75-cM interval on chromosome arm 7AL.The contributions and interactions of both major QTLs were further analyzed and discussed.The effect of QSns.sau-2SY-7A was successfully validated by developing a tightly linked kompetitive allele specific PCR marker in an F_(2:3) population and a panel of 101 high-generation breeding wheat lines.Furthermore,several genes including the previously reported WHEAT ORTHOLOG OF APO1(WAPO1),an ortholog of the rice gene ABERRANT PANICLE ORGANIZATION 1(APO1)related to SNS,were predicted in the interval of QSns.sau-2SY-7A.In summary,these results revealed the genetic basis of the multi-spikelet genotype of wheat line 20828 and will facilitate subsequent fine mapping and breeding utilization of the major QTLs.展开更多
The objective of the current study was to develop a validated, specific and stability-indicating reverse phase liquid chromatographic method for the quantitative determination of fluocinonide and its related substance...The objective of the current study was to develop a validated, specific and stability-indicating reverse phase liquid chromatographic method for the quantitative determination of fluocinonide and its related substances. The determination was done for active pharmaceutical ingredient and its pharmaceutical dosage forms in the presence of degradation products, and its process-related impurities. The drug was subjected to stress condi- tions of hydrolysis (acid and base), oxidation, photolysis and thermal degradation per International Confer- ence on Harmonization (ICH) prescribed stress conditions to show the stability- indicating power of the method. Significant degradation was observed during acid, base hydrolysis, and peroxide degradation. The major degradants were identified by LC-MS, FTIR and 1H/13C NMR spectral analysis. The chromatographic conditions were optimized using an impurity-spiked solution and the samples generated from forced degra- dation studies. In the developed HPLC method, the resolution between fluocinonide and its process-related impurities, (namely imp-1, imp-2, imp-3, imp-4, imp-5, imp-6, imp-7 and imp-8) and its degradation products was found to be greater than 2.0.The chromatographic separation was achieved on a C18, 250 mm × 4.6 mm, 5 μm column. The LC method employed a linear gradient elution and the detection wavelength was set at 240 nm. The stress samples were assayed against a qualified reference standard and the mass balance was found to be close to 99.3%. The developed RP-LC method was validated with respect to linearity, accuracy, precision and robustness.展开更多
Melatonin is a natural hormone and with the advancement of age its production declines and thereby may result in some neurological disorders. Exogenous administration of melatonin has been suggested as a neuroprotecti...Melatonin is a natural hormone and with the advancement of age its production declines and thereby may result in some neurological disorders. Exogenous administration of melatonin has been suggested as a neuroprotective agent. Due to its low oral bioavailability, the loading of melatonin in polymeric nanoparticles could be an important tool to effectively use exogenous melatonin. The quantification of the incorporated drug within polymeric nanoparticles is an important step in nanoparticles characterization. An analytical method using high performance liquid chromatography equipped with photodiode array detector (HPLC-PDA) was developed and validated for melatonin determination in poly (lactic acid) nanoparticles obtained by a single emulsion-solvent evaporation technique. The melatonin in vitro release profile also was determined by the HPLC method. Mobile phase consisted of acetonitrile: water (65:35, v/v) pumped at a flow rate of 0.9 mL/min, in the isocratic mode and PDA detector was set at 220 nm. The method was validated in terms of the selectivity, linearity, precision, accuracy, robustness, limits of detection and quantification. Analytical curve was linear over the concentration range of 10-100 ~tg/mL, and limits of detection and quantification were 25.9 ng/mL and 78.7 ng/mL, respectively. The mean recovery for melatonin was 100.47% (RSD = 1.25%, n = 9). In the intra- and inter- assay, the coefficient of variation was less than 2%. Robustness was proved performing changes in mobile phase, column temperature and flow rate. The method was suitable for the determination of melatonin encapsulation efficiency in poly(lactic acid) nanopartieles and for the evaluation of melatonin in vitro release profile.展开更多
A simple, rapid, precise, accurate, rugged and robust stability-indicating ultra-fast high performance liquid chromatographic (UHPLC) method has been developed for the estimation of related compounds (imp-A, imp-B, im...A simple, rapid, precise, accurate, rugged and robust stability-indicating ultra-fast high performance liquid chromatographic (UHPLC) method has been developed for the estimation of related compounds (imp-A, imp-B, imp-C, imp-D and imp-E) in Naproxen and also the assay of Naproxen from bulk drug samples. The stability indicating capability of the method was proven by subjecting the samples to stress conditions such as acid, base, oxidation, photolysis and thermal degradation. The efficient chromatographic separation was achieved using mobile phase solution A prepared as buffer solution 10 mM monobasic potassium phosphate pH 4.0 ± 0.05 adjusted with diluted ortho phosphoric acid solution and solution B acetonitrile with linear gradient elution on poroshell 120 EC-C18 shot column (50 mm × 4.6 mm, 2.7 μm) and UV detection at 235 nm at a flow rate 1.0 mL/min, column oven temperature was set to 25?C. The above are all known impurities and degradation impurities are well resolved with Naproxen peak and these are eluted within a 10 min runtime of HPLC. The photo diode array detector was used for peak homogeneity testing during stress study experiments and the overall mass balance was found to be 99.2% to 100.2% in all stress conditions. The linear calibration range was found to be 0.05 μg/mL to 0.75 μg/mL for related compounds and 50 μg/mL to 150 μg/mL for Naproxen and the accuracy of the method was found to be 91.5% to 98.5% recovery for the related substance method and 95.4% to 97.4% recovery for the assay method. The Naproxen and related compounds were found to be stable up to 48 hours and the method validation data show excellent results for precision, linearity, specificity, limit of detection, limit of quantitation and robustness. The present method can be successfully used for routine QC and stability studies and it will help to reduce the analysis cost, time and effluent load compared to conventional HPLC methods.展开更多
A modified ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the quantitation of ibuprofen enantiomers in human plasma. Ibuprofen and flurbiprofen (in...A modified ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the quantitation of ibuprofen enantiomers in human plasma. Ibuprofen and flurbiprofen (internal standard) were extracted from human plasma at acidic pH, using a single-step liquid-liquid extraction with methyl-tert-butyl ether. The enantiomers of ibuprofen and flurbiprofen were derivatized to yield the corresponding diastereomers. Chromatographic separation was achieved using a phenyl column with a run time of 20 min. (R)- and (S)-ibuprofen were quantitated at the multiple reaction monitoring (MRM) transition of m/z 360.2 ? 232.1, and (R)- and (S)-flurbiprofen were monitored at the MRM transition of m/z 398.3 ? 270.1. The method was validated for accuracy, precision, linearity, range, limit of quantitation (LOQ), limit of detection (LOD), selectivity, absolute recovery, matrix effect, dilution integrity, and evaluation of carry-over. Accuracy for (R)-ibuprofen ranged between –11.8% and 11.2%, and for (S)-ibuprofen between –8.6% and –0.3%. Precision for (R)-ibuprofen was ≤ 11.2%, and for (S)-ibuprofen ≤ 7.0%. The calibration curves were weighted (1/X2, n = 7) and were linear with r2 for (R)-ibuprofen ≥ 0.988 and for (S)-ibuprofen ≥ 0.990. The range of the method was 50 to 5000 ng/mL with the LOQ of 50 ng/mL, and LOD of 1 ng/mL, for (R)- and (S)-ibuprofen requiring 100 μL of sample. The method was applied successfully to a pharmacokinetic study with the administration of a single oral dose of ibuprofen capsules to human subjects.展开更多
A stability indicating LC method was developed for the simultaneous determination of Amlodipine and Benazepril capsules in pharmaceutical dosage form. Efficient chromatographic separation was achieved on Symmetry C18 ...A stability indicating LC method was developed for the simultaneous determination of Amlodipine and Benazepril capsules in pharmaceutical dosage form. Efficient chromatographic separation was achieved on Symmetry C18 stationary phase with simple combination of amobile phase containing 750 mL of DI Water, 250 mL of Acetonitrile and 2 mL of Octylamine into suitable container with adjusted pH to 2.50 ± 0.05 with the aid of Ortho phosphoric acid delivered in an isocratic mode and quantification was carried out using UV detection at 240 nm at a flow rate of 1.0 mL·min-1 with an injection volume of 20 μl and ambient column temperature. This method is capable to detect both the drug components of Amlodipine and Benazepril in presence of their degradation products (Amlodipine Imp-A and Benazepril Impurity-C) with a detection level of 0.05%. Amlodipine/Benazepril in their combination drug product were exposed to thermal, photolytic, hydrolytic and oxidative stress conditions, and the samples were analysed. Peak homogeneity data of Amlodipine and Benazeprilis were obtained using PDA detector, in the stressed sample chromatograms, demonstrating the specificity. The method shows excellent linearity over a range of 0.05%-2.0% for Amlodipine, Amlodipine Impurity-A and 0.05%-5.0% for Benazepril and Benazepril Impurity-C. The correlation coefficient for Amlodipine and Benazepril is 1. The relative standard deviation was always less than 2%. The proposed method was found to be suitable and accurate for quantitative determination and the stability study of Amlodipine and Benazepril in pharmaceutical preparations. The developed HPLC method was validated with respect to linearity & range, accuracy, precision and robustness.展开更多
A novel and sensitive stability indicating RP-HPLC method has been developed for the quantitative determination of amlexanox in bulk drugs. The separation was accomplished on C18 column using 10 mM ammonium dihydrogen...A novel and sensitive stability indicating RP-HPLC method has been developed for the quantitative determination of amlexanox in bulk drugs. The separation was accomplished on C18 column using 10 mM ammonium dihydrogen orthophosphate (pH adjusted to 4.8 by using ortho phosphoric acid) and methanol (30:70 v/v) as mobile phase in an isocratic elution mode at a flow rate of 1.0 mL min-1. The eluents were monitored by PDA detector at 245 nm. The drug was subjected to stress conditions of hydrolysis, oxidation, photolysis and thermal degradation. Significant degradation was found under basic, acidic stress and UV light. The resolution (Rs) between amlexanox and its degradation products was found to be greater than 2.5. Regression analysis shows correlation coefficient greater than 0.999 for amlexanox. The inter and intraday precision values for amlexanox were found to be within 1.0% RSD. The method has shown good and consistent recoveries for amlexanox in bulk drugs (98.86% - 101.05%). The developed method was validated with respect to linearity, accuracy, precision and robustness.展开更多
A novel, sensitive, stability indicating RP-LC method has been developed for the quantitative determination of Varde- nafil and its related impurities in both bulk drugs and Pharmaceutical dosage forms. Effective chro...A novel, sensitive, stability indicating RP-LC method has been developed for the quantitative determination of Varde- nafil and its related impurities in both bulk drugs and Pharmaceutical dosage forms. Effective chromatographic separation was achieved on a C18 stationary phase with simple mobile phase combination delivered in a simple gradient pro- gramme and quantitation was by ultraviolet detection at 210 nm. The mobile phase consisted of a buffer and acetonitrile delivered at a flow rate 0.25 ml?min–1. Buffer consisted of 20 mM Ammonium bi carbonate, pH adjusted to 5.0 by using ortho Phosphoric acid. In the developed UPLC method the resolution (Rs) between vardenafil and its four potential impurities was found to be grater than 2.0.Regrreation analysis showed an r value (correlation coefficient) grater than 0.999 for vardenafil and its four impurities. This method was capable to detect all four impurities of vardenafil at a level of 0.25 μg.mL–1 with respect to test concentration of 500 μg?ml–1 for a 2 μl injection volume. The inter and intra day precision values for all four impurities and for vardenafil was found to be with in 2.0% RSD. The method showed good and consistent recoveries for vardenafil in bulk drugs (98.8% - 100.9%), pharmaceutical dosage forms (100.5% - 101.5%) and its all four impurities (99.8% - 102.5%).The test solutions was found to stable in acetonitrile for 48 h. The drug was subjected to stress conditions of hydrolysis, oxidation, photolysis, and thermal degradation. Considerable degradation was found to occur in peroxide hydrolysis. The stress samples were assayed against a qualified reference standard and the mass balance was found close to 99.9%. The developed RP-LC method was validated with respect to linearity, accuracy, precision and robustness.展开更多
This research article describes stability indicating fast liquid chromatographic method for determination of chromatographic purity and assay of Nizatidine as a alternate for two different methods for chromatographic ...This research article describes stability indicating fast liquid chromatographic method for determination of chromatographic purity and assay of Nizatidine as a alternate for two different methods for chromatographic purity and assay as given in USP Monograph and Ph.Eur Monograph. Proposed method is developed on Waters symmetry RP18 (50 × 4.6 mm), 3.5 μm stationary phase using gradient elution with combination of Ammonium acetate Diethyl amine buffer, Methanol and Tetrahydrofuran as mobile phase. Favorable results are obtained under developed conditions, which guarantee good separation of studied components. Whereas, data obtained from method validation confirm specificity, high sensitivity, linearity in a range of studied concentrations, repeatability and good accuracy of this method. Considerable degradation observed in oxidation stress condition was detected by this method. Eight impurities are studied among which impurity-5 is found major degradant. The stress samples are assayed against a qualified standard and the mass balance is found close to 99.2%. The developed method can be used for routine samples as well as stability studies.展开更多
The internal standard (IS) method is the best method for the analysis of samples, as it is independent of errors in injection volume, changes in sample volumes, and changes in sensitivity of the detector, etc. Use of ...The internal standard (IS) method is the best method for the analysis of samples, as it is independent of errors in injection volume, changes in sample volumes, and changes in sensitivity of the detector, etc. Use of an internal standard allows for the correction of losses due to sample clean-up of complex samples. An ideal IS is a compound that has properties very similar to, and that behaves as the compounds to be analysed. Ideally, only in the last step of analysis (HPLC), the IS should be well separated from the compounds of the mixture to be analysed. After testing several existing compounds with negative results, we decided to synthesise the 19-O-β-D-galactopyranosyl-13-O-β-D-glucopyranosyl-steviol as IS. This is the 19-galactosyl ester of steviolmonoside (13-O-β-D-glucopyranosyl-steviol). The IS was made according to published methods. Steviolmonoside (SM) was made from purified commercial rubusoside (Rub) by refluxing it in 10% KOH for 2 h. SM was precipitated and crystallized from MeOH. The hydroxyls of the glucose unit of SM were protected by acetylation. The acetylated SM was crystallized from acetone and dissolved in 1,2-dichloroethane. Then Ag2CO3 on Celite and tetra-acetylated galactopyranosyl bromide were added and the mixture was refluxed for 2 h. After cooling, BaO in MeOH was added to remove the acetyl groups. The 1,2-dichloroethane fraction was then extracted three times with equal volumes of water and the water fraction containing the IS was further purified on a C18 flash chromatography column. Traces of unreacted SM were removed by preparative HPLC on an Alltima C18 column (250 mm × 22 mm, particle size 10 μm) with AcCN:water (35:65, 20 ml/min). Detection was at 210 nm (KNAUER, “Smartline” UV detector 2500). The collected IS fraction from the HPLC was completely dried. Mixtures of steviol glycosides (SVglys) containing IS could be purified over SPE cartridges without change of the SVgly over IS ratio. The calibration curves for rebaudioside A (RebA) and stevioside (ST) were linear between 0.012 and 0.95 and between 0.013 and 1.13 mM for RebA and ST, respectively. The accuracy was checked by the standard addition method. It was concluded that the IS method gives an excellent precision and accuracy.展开更多
A novel stability indicating reverse phase ultra performance liquid chromatographic (UP-LC) method has been developed for Etravirine along with eight impurities (imp-1, imp-2, imp-3, imp-4, imp-5, imp-6, imp-7 and imp...A novel stability indicating reverse phase ultra performance liquid chromatographic (UP-LC) method has been developed for Etravirine along with eight impurities (imp-1, imp-2, imp-3, imp-4, imp-5, imp-6, imp-7 and imp-8) and validated as per ICH recommendations. Stress degradation conditions were established for Etravirine by subjecting it to stress conditions of acid, base, oxidation, humidity, thermal and photolysis. Significant degradation is observed in base stress condition and the major degradant (RRT at about 0.94) is identified by LC-MS and spectral analysis. The stress samples were assayed against a qualified reference standard and the mass balance was found close to 99.0%. Efficient chromatographic separation was achieved on a Shimpack ODS-II stationary phase with a gradient mobile phase combination. Quantification was carried at 303 nm at a flow rate of 0.6 mL?min–1. The resolution between Etravirine and eight potential impurities is found to be greater than 2.0. Regression analysis shows as r value (correlation coefficient) of greater than 0.999 for Etravirine and eight potential impurities. This method is capable to detect the impurities of Etravirine at a level of 0.003% with respect to test concentration of 1.0 mg·mL–1.展开更多
Degradation pathway for pitavastatin calcium is established as per ICH recommendations by validated and stability indicating reverse phase liquid chromatographic method. Pitavastatin is subjected to stress conditions ...Degradation pathway for pitavastatin calcium is established as per ICH recommendations by validated and stability indicating reverse phase liquid chromatographic method. Pitavastatin is subjected to stress conditions of acid, base, oxidation, thermal and photolysis. Significant degradation is observed in acid and base stress conditions. Four impurities are studied among which impurity-4 is found prominent degradant. The stress samples are assayed against a qualified reference standard and the mass balance is found close to 99.5%. Efficient chromatographic separation is achieved on a BEH C18 stationary phase with simple mobile phase combination delivered in gradient mode and quantification is carried at 245 nm at a flow rate of 0.3 mL min-1. In the developed UPLC method the resolution between pitavastatin calcium and four potential impurities is found to be greater than 4.0. Regression analysis shows an r value (correlation coefficient) of greater than 0.998 for pitavastatin calcium and four potential impurities. This method is capable to detect the impurities of pitavastatin calcium at a level of 0.006% with respect to test concentration of 0.10 mg/mL for a 2-μL injection volume. The developed UPLC method is validated with respect to specificity, linearity & range, accuracy, precision and robustness for impurities determination and assay determination.展开更多
Degradation pathway for gefitinib is established as per ICH recommendations by validated and stability in-dicating reverse phase liquid chromatographic method. Gefitinib is subjected to stress conditions of acid, base...Degradation pathway for gefitinib is established as per ICH recommendations by validated and stability in-dicating reverse phase liquid chromatographic method. Gefitinib is subjected to stress conditions of acid, base, oxidation, thermal and photolysis. Significant degradation is observed in acid and base stress condi-tions. Two impurities are studied among which one impurity is found prominent degradant. The stress sam-ples are assayed against a qualified reference standard and the mass balance is found close to 99.5%. Effi-cient chromatographic separation is achieved on a Agilent make XDB-C18, 50 × 4.6 mm with 1.8 μm parti-cles stationary phase with simple mobile phase combination delivered in gradient mode and quantification is carried at 250 nm at a flow rate of 0.5 mL?min-1. In the developed RPLC method the resolution between ge-fitinib and the potential impurities is found to be greater than 5.0. Regression analysis shows an r value (cor-relation coefficient) of greater than 0.998 for gefitinib and the two potential impurities. This method is capa-ble to detect the impurities of gefitinib at a level of 0.01% with respect to test concentration of 0.5 mg?mL-1 for a 4-μL injection volume. The developed RRLC method is validated with respect to specificity, linearity & range, accuracy, precision and robustness for impurities determination and assay determination.展开更多
A simple, precise and accurate high performance thin layer chromatographic method has been developed for the simultaneous estimation of Isotretinoin and Erythromycin in pharmaceutical gel. The separation was carried o...A simple, precise and accurate high performance thin layer chromatographic method has been developed for the simultaneous estimation of Isotretinoin and Erythromycin in pharmaceutical gel. The separation was carried out on Merck TLC aluminum sheets of silica gel 60 F254, (20 × 10 cm) with 250 μm thickness using toluene: DMSO: methanol (6.5:0.2:2.5, v/v/v) as a mobile phase. HPTLC separation of the two drugs followed by densitometric measurement of their spots at 340 nm for Isotretinoin before derivatization and 410 nm for Erythromycin after derivatization with 10% H2SO4 and heating at 100°C for 15 min. The drugs were satisfactorily resolved with RF values of 0.38 ± 0.02 and 0.55 ± 0.02 for Isotretinoin and Erythromycin, respectively. The accuracy and reliability of the method was assessed by evaluation of linearity (30-150 ng spot-1 for Isotretinoin and 1200-6000 ng spot-1 for Erythromycin), precision (intra-day RSD 0.62-0.79% and inter-day RSD 0.43-0.71 % for Isotretinoin and intra-day RSD 0.47-1.71 % and inter-day RSD 0.42-1.49 % for Erythromycin), accuracy (98.91 ± 0.92 % for Isotretinoin and 99.27 ± 0.72 % for Erythromycin), and specificity, in accordance with ICH guidelines.展开更多
A simple efficient isocratic reversed-phase HPLC method was developed and validated for the determination of clindamycin palmitate hydrochloride (CPH) and its commercially available oral solution products. Separation ...A simple efficient isocratic reversed-phase HPLC method was developed and validated for the determination of clindamycin palmitate hydrochloride (CPH) and its commercially available oral solution products. Separation was achieved on a Phenomenex Zorbax (Luna) cyano column (150 × 4.6 mm, 5 μm) with a Phenomenex cyano guard cartridge (4 × 3.0 mm) on Agilent 1050 series HPLC system. CPH and its resolution standard lincomycin were eluted isocratically at a flow rate of 1 mL/min with a simplified mobile phase (potassium phosphate buffer (5 mM, pH 3.0)—acetonitrile—tetrahydrofuran (20:75:5, v/v/v)) and detected at 210 nm. The column was maintained at 25?C. The method was validated according to USP category I requirements. Robustness and forced degradation studies were also conducted. CPH marketed drug products were obtained from a drug distributor and assayed for potency using the validated method. Validation acceptance criteria were met in all cases. The analytical range for CPH was 15 - 500 μg/mL and the linearity was r2 > 0.999 over three days. The method was determined to be specific and robust. Both accuracy (92.0% - 103.8%) and precision (0.67% - 1.52%) were established across the analytical range for low, intermediate and high QC concentrations. Method applicability was demonstrated by analyzing two marketed products of CPH, in which results showed potency >98%. The method was determined to be an enhancement over the current USP methodology for assay as a result of increased efficiency, reduced organic solvents and the elimination of matrix modifiers. This method was successfully applied for the quality assessment of: 1) currently marketed drug products and 2) will in future assess the product quality of novel dosage forms of CPH for pediatric use.展开更多
ABSTRACT A simple, economic, and time-efficient related substance, GC method has been developed for the analysis of 1,4-Cyclohexanedione mono- ethylene ketal(will be specified as ketal) in the presence of a potential ...ABSTRACT A simple, economic, and time-efficient related substance, GC method has been developed for the analysis of 1,4-Cyclohexanedione mono- ethylene ketal(will be specified as ketal) in the presence of a potential impurity 1,4-cyclohexa- nedione bis (ethylene ketal) [will be specified as diketal]. Successful chromatographic separa- tion of the ketal from the impurity was achieved on a DBWAX ETR, 30 m x 0.32 mm x 1.0μ FT column with nitrogen as carrier gas and FID detector. The method was validated for linearity, accuracy, precision, and specificity and can be used for quality control during manufacture of ketal. A validated GC method is reported for the ketal for the first time.展开更多
文摘With the maturation and advancement of blockchain technology,a novel execute-order-validate(EOV)architecture has been proposed,allowing transactions to be executed in parallel during the execution phase.However,parallel execution may lead to multi-version concurrency control(MVCC)conflicts during the validation phase,resulting in transaction invalidation.Based on different causes,we categorize conflicts in the EOV blockchain into two types:within-block conflicts and cross-block conflicts,and propose an optimization solution called FabricMan based on Fabric v2.4.For within-block conflicts,a reordering algorithm is designed to improve the transaction success rate and parallel validation is implemented based on the transaction conflict graph.We also merge transfer transactions to prevent triggering multiple version checks.For cross-block conflicts,a cache-based version validation mechanism is implemented to detect and terminate invalid transactions in advance.Experimental comparisons are conducted between FabricMan and two other systems,Fabric and Fabric++.The results show that FabricMan outperforms the other two systems in terms of throughput,transaction abort rate,algorithm execution time,and other experimental metrics.
文摘Although a number of methods are available for evaluating Linezolid and its possible impurities, a common method for separation if its potential impurities, degradants and enantiomer in a single method with good efficiency remain unavailable. With the objective of developing an advanced method with shorter runtimes, a simple, precise, accurate stability-indicating LC method was developed for the determination of purity of Linezolid drug substance and drug products in bulk samples and pharmaceutical dosage forms in the presence of its impurities and degradation products. This method is capable of separating all the related substances of Linezolid along with the chiral impurity. This method can also be used for the estimation of assay of Linezolid in drug substance as well as in drug product. The method was developed using Chiralpak IA (250 mm 4.6 mm, 5 mm) column. A mixture of acetonitrile, ethanol, n-butyl amine and trifluoro acetic acid in 96:4:0.10:0.16 (v/v/v/v) ratio was used as a mobile phase. The eluted compounds were monitored at 254 nm. Linezolid was subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal and photolytic degradation. The degradation products were well resolved from main peak and its impurities, proving the stability-indicating power of the method. The developed method was validated as per International Conference on Harmonization (ICH) guidelines with respect to specificity, limit of detection, limit of quantification, precision, linearity, accuracy, robustness and system suitability.
基金supported by the projects from the Applied Basic Research Programs of Science and Technology Department of Sichuan Province, China (2020YJ0140 and 2021YJ0503)the International Science and Technology Cooperation and Exchanges Program of Science and Technology Department of Sichuan Province, China (2021YFH0083 and 2022YFH0053)+1 种基金the National Natural Science Foundation of China (31971937 and 31970243)the Key Projects of Scientific and Technological Activities for Overseas Students of Sichuan Province, China
文摘The spikelet number per spike(SNS)contributes greatly to grain yield in wheat.Identifying various genes that control wheat SNS is vital for yield improvement.This study used a recombinant inbred line population genotyped by the Wheat55K single-nucleotide polymorphism array to identify two major and stably expressed quantitative trait loci(QTLs)for SNS.One of them(QSns.sau-2SY-2D.1)was reported previously,while the other(QSns.sau-2SY-7A)was newly detected and further analyzed in this study.QSns.sau-2SY-7A had a high LOD value ranging from 4.46 to 16.00 and explained 10.21-40.78%of the phenotypic variances.QSns.sau-2SY-7A was flanked by the markers AX-110518554 and AX-110094527 in a 4.75-cM interval on chromosome arm 7AL.The contributions and interactions of both major QTLs were further analyzed and discussed.The effect of QSns.sau-2SY-7A was successfully validated by developing a tightly linked kompetitive allele specific PCR marker in an F_(2:3) population and a panel of 101 high-generation breeding wheat lines.Furthermore,several genes including the previously reported WHEAT ORTHOLOG OF APO1(WAPO1),an ortholog of the rice gene ABERRANT PANICLE ORGANIZATION 1(APO1)related to SNS,were predicted in the interval of QSns.sau-2SY-7A.In summary,these results revealed the genetic basis of the multi-spikelet genotype of wheat line 20828 and will facilitate subsequent fine mapping and breeding utilization of the major QTLs.
文摘The objective of the current study was to develop a validated, specific and stability-indicating reverse phase liquid chromatographic method for the quantitative determination of fluocinonide and its related substances. The determination was done for active pharmaceutical ingredient and its pharmaceutical dosage forms in the presence of degradation products, and its process-related impurities. The drug was subjected to stress condi- tions of hydrolysis (acid and base), oxidation, photolysis and thermal degradation per International Confer- ence on Harmonization (ICH) prescribed stress conditions to show the stability- indicating power of the method. Significant degradation was observed during acid, base hydrolysis, and peroxide degradation. The major degradants were identified by LC-MS, FTIR and 1H/13C NMR spectral analysis. The chromatographic conditions were optimized using an impurity-spiked solution and the samples generated from forced degra- dation studies. In the developed HPLC method, the resolution between fluocinonide and its process-related impurities, (namely imp-1, imp-2, imp-3, imp-4, imp-5, imp-6, imp-7 and imp-8) and its degradation products was found to be greater than 2.0.The chromatographic separation was achieved on a C18, 250 mm × 4.6 mm, 5 μm column. The LC method employed a linear gradient elution and the detection wavelength was set at 240 nm. The stress samples were assayed against a qualified reference standard and the mass balance was found to be close to 99.3%. The developed RP-LC method was validated with respect to linearity, accuracy, precision and robustness.
基金supported by Comissao de Aperfeicoamento de Pessoal do Nível Superior(CAPES)in the form of scholarship for LGM
文摘Melatonin is a natural hormone and with the advancement of age its production declines and thereby may result in some neurological disorders. Exogenous administration of melatonin has been suggested as a neuroprotective agent. Due to its low oral bioavailability, the loading of melatonin in polymeric nanoparticles could be an important tool to effectively use exogenous melatonin. The quantification of the incorporated drug within polymeric nanoparticles is an important step in nanoparticles characterization. An analytical method using high performance liquid chromatography equipped with photodiode array detector (HPLC-PDA) was developed and validated for melatonin determination in poly (lactic acid) nanoparticles obtained by a single emulsion-solvent evaporation technique. The melatonin in vitro release profile also was determined by the HPLC method. Mobile phase consisted of acetonitrile: water (65:35, v/v) pumped at a flow rate of 0.9 mL/min, in the isocratic mode and PDA detector was set at 220 nm. The method was validated in terms of the selectivity, linearity, precision, accuracy, robustness, limits of detection and quantification. Analytical curve was linear over the concentration range of 10-100 ~tg/mL, and limits of detection and quantification were 25.9 ng/mL and 78.7 ng/mL, respectively. The mean recovery for melatonin was 100.47% (RSD = 1.25%, n = 9). In the intra- and inter- assay, the coefficient of variation was less than 2%. Robustness was proved performing changes in mobile phase, column temperature and flow rate. The method was suitable for the determination of melatonin encapsulation efficiency in poly(lactic acid) nanopartieles and for the evaluation of melatonin in vitro release profile.
文摘A simple, rapid, precise, accurate, rugged and robust stability-indicating ultra-fast high performance liquid chromatographic (UHPLC) method has been developed for the estimation of related compounds (imp-A, imp-B, imp-C, imp-D and imp-E) in Naproxen and also the assay of Naproxen from bulk drug samples. The stability indicating capability of the method was proven by subjecting the samples to stress conditions such as acid, base, oxidation, photolysis and thermal degradation. The efficient chromatographic separation was achieved using mobile phase solution A prepared as buffer solution 10 mM monobasic potassium phosphate pH 4.0 ± 0.05 adjusted with diluted ortho phosphoric acid solution and solution B acetonitrile with linear gradient elution on poroshell 120 EC-C18 shot column (50 mm × 4.6 mm, 2.7 μm) and UV detection at 235 nm at a flow rate 1.0 mL/min, column oven temperature was set to 25?C. The above are all known impurities and degradation impurities are well resolved with Naproxen peak and these are eluted within a 10 min runtime of HPLC. The photo diode array detector was used for peak homogeneity testing during stress study experiments and the overall mass balance was found to be 99.2% to 100.2% in all stress conditions. The linear calibration range was found to be 0.05 μg/mL to 0.75 μg/mL for related compounds and 50 μg/mL to 150 μg/mL for Naproxen and the accuracy of the method was found to be 91.5% to 98.5% recovery for the related substance method and 95.4% to 97.4% recovery for the assay method. The Naproxen and related compounds were found to be stable up to 48 hours and the method validation data show excellent results for precision, linearity, specificity, limit of detection, limit of quantitation and robustness. The present method can be successfully used for routine QC and stability studies and it will help to reduce the analysis cost, time and effluent load compared to conventional HPLC methods.
文摘A modified ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the quantitation of ibuprofen enantiomers in human plasma. Ibuprofen and flurbiprofen (internal standard) were extracted from human plasma at acidic pH, using a single-step liquid-liquid extraction with methyl-tert-butyl ether. The enantiomers of ibuprofen and flurbiprofen were derivatized to yield the corresponding diastereomers. Chromatographic separation was achieved using a phenyl column with a run time of 20 min. (R)- and (S)-ibuprofen were quantitated at the multiple reaction monitoring (MRM) transition of m/z 360.2 ? 232.1, and (R)- and (S)-flurbiprofen were monitored at the MRM transition of m/z 398.3 ? 270.1. The method was validated for accuracy, precision, linearity, range, limit of quantitation (LOQ), limit of detection (LOD), selectivity, absolute recovery, matrix effect, dilution integrity, and evaluation of carry-over. Accuracy for (R)-ibuprofen ranged between –11.8% and 11.2%, and for (S)-ibuprofen between –8.6% and –0.3%. Precision for (R)-ibuprofen was ≤ 11.2%, and for (S)-ibuprofen ≤ 7.0%. The calibration curves were weighted (1/X2, n = 7) and were linear with r2 for (R)-ibuprofen ≥ 0.988 and for (S)-ibuprofen ≥ 0.990. The range of the method was 50 to 5000 ng/mL with the LOQ of 50 ng/mL, and LOD of 1 ng/mL, for (R)- and (S)-ibuprofen requiring 100 μL of sample. The method was applied successfully to a pharmacokinetic study with the administration of a single oral dose of ibuprofen capsules to human subjects.
文摘A stability indicating LC method was developed for the simultaneous determination of Amlodipine and Benazepril capsules in pharmaceutical dosage form. Efficient chromatographic separation was achieved on Symmetry C18 stationary phase with simple combination of amobile phase containing 750 mL of DI Water, 250 mL of Acetonitrile and 2 mL of Octylamine into suitable container with adjusted pH to 2.50 ± 0.05 with the aid of Ortho phosphoric acid delivered in an isocratic mode and quantification was carried out using UV detection at 240 nm at a flow rate of 1.0 mL·min-1 with an injection volume of 20 μl and ambient column temperature. This method is capable to detect both the drug components of Amlodipine and Benazepril in presence of their degradation products (Amlodipine Imp-A and Benazepril Impurity-C) with a detection level of 0.05%. Amlodipine/Benazepril in their combination drug product were exposed to thermal, photolytic, hydrolytic and oxidative stress conditions, and the samples were analysed. Peak homogeneity data of Amlodipine and Benazeprilis were obtained using PDA detector, in the stressed sample chromatograms, demonstrating the specificity. The method shows excellent linearity over a range of 0.05%-2.0% for Amlodipine, Amlodipine Impurity-A and 0.05%-5.0% for Benazepril and Benazepril Impurity-C. The correlation coefficient for Amlodipine and Benazepril is 1. The relative standard deviation was always less than 2%. The proposed method was found to be suitable and accurate for quantitative determination and the stability study of Amlodipine and Benazepril in pharmaceutical preparations. The developed HPLC method was validated with respect to linearity & range, accuracy, precision and robustness.
文摘A novel and sensitive stability indicating RP-HPLC method has been developed for the quantitative determination of amlexanox in bulk drugs. The separation was accomplished on C18 column using 10 mM ammonium dihydrogen orthophosphate (pH adjusted to 4.8 by using ortho phosphoric acid) and methanol (30:70 v/v) as mobile phase in an isocratic elution mode at a flow rate of 1.0 mL min-1. The eluents were monitored by PDA detector at 245 nm. The drug was subjected to stress conditions of hydrolysis, oxidation, photolysis and thermal degradation. Significant degradation was found under basic, acidic stress and UV light. The resolution (Rs) between amlexanox and its degradation products was found to be greater than 2.5. Regression analysis shows correlation coefficient greater than 0.999 for amlexanox. The inter and intraday precision values for amlexanox were found to be within 1.0% RSD. The method has shown good and consistent recoveries for amlexanox in bulk drugs (98.86% - 101.05%). The developed method was validated with respect to linearity, accuracy, precision and robustness.
文摘A novel, sensitive, stability indicating RP-LC method has been developed for the quantitative determination of Varde- nafil and its related impurities in both bulk drugs and Pharmaceutical dosage forms. Effective chromatographic separation was achieved on a C18 stationary phase with simple mobile phase combination delivered in a simple gradient pro- gramme and quantitation was by ultraviolet detection at 210 nm. The mobile phase consisted of a buffer and acetonitrile delivered at a flow rate 0.25 ml?min–1. Buffer consisted of 20 mM Ammonium bi carbonate, pH adjusted to 5.0 by using ortho Phosphoric acid. In the developed UPLC method the resolution (Rs) between vardenafil and its four potential impurities was found to be grater than 2.0.Regrreation analysis showed an r value (correlation coefficient) grater than 0.999 for vardenafil and its four impurities. This method was capable to detect all four impurities of vardenafil at a level of 0.25 μg.mL–1 with respect to test concentration of 500 μg?ml–1 for a 2 μl injection volume. The inter and intra day precision values for all four impurities and for vardenafil was found to be with in 2.0% RSD. The method showed good and consistent recoveries for vardenafil in bulk drugs (98.8% - 100.9%), pharmaceutical dosage forms (100.5% - 101.5%) and its all four impurities (99.8% - 102.5%).The test solutions was found to stable in acetonitrile for 48 h. The drug was subjected to stress conditions of hydrolysis, oxidation, photolysis, and thermal degradation. Considerable degradation was found to occur in peroxide hydrolysis. The stress samples were assayed against a qualified reference standard and the mass balance was found close to 99.9%. The developed RP-LC method was validated with respect to linearity, accuracy, precision and robustness.
文摘This research article describes stability indicating fast liquid chromatographic method for determination of chromatographic purity and assay of Nizatidine as a alternate for two different methods for chromatographic purity and assay as given in USP Monograph and Ph.Eur Monograph. Proposed method is developed on Waters symmetry RP18 (50 × 4.6 mm), 3.5 μm stationary phase using gradient elution with combination of Ammonium acetate Diethyl amine buffer, Methanol and Tetrahydrofuran as mobile phase. Favorable results are obtained under developed conditions, which guarantee good separation of studied components. Whereas, data obtained from method validation confirm specificity, high sensitivity, linearity in a range of studied concentrations, repeatability and good accuracy of this method. Considerable degradation observed in oxidation stress condition was detected by this method. Eight impurities are studied among which impurity-5 is found major degradant. The stress samples are assayed against a qualified standard and the mass balance is found close to 99.2%. The developed method can be used for routine samples as well as stability studies.
文摘The internal standard (IS) method is the best method for the analysis of samples, as it is independent of errors in injection volume, changes in sample volumes, and changes in sensitivity of the detector, etc. Use of an internal standard allows for the correction of losses due to sample clean-up of complex samples. An ideal IS is a compound that has properties very similar to, and that behaves as the compounds to be analysed. Ideally, only in the last step of analysis (HPLC), the IS should be well separated from the compounds of the mixture to be analysed. After testing several existing compounds with negative results, we decided to synthesise the 19-O-β-D-galactopyranosyl-13-O-β-D-glucopyranosyl-steviol as IS. This is the 19-galactosyl ester of steviolmonoside (13-O-β-D-glucopyranosyl-steviol). The IS was made according to published methods. Steviolmonoside (SM) was made from purified commercial rubusoside (Rub) by refluxing it in 10% KOH for 2 h. SM was precipitated and crystallized from MeOH. The hydroxyls of the glucose unit of SM were protected by acetylation. The acetylated SM was crystallized from acetone and dissolved in 1,2-dichloroethane. Then Ag2CO3 on Celite and tetra-acetylated galactopyranosyl bromide were added and the mixture was refluxed for 2 h. After cooling, BaO in MeOH was added to remove the acetyl groups. The 1,2-dichloroethane fraction was then extracted three times with equal volumes of water and the water fraction containing the IS was further purified on a C18 flash chromatography column. Traces of unreacted SM were removed by preparative HPLC on an Alltima C18 column (250 mm × 22 mm, particle size 10 μm) with AcCN:water (35:65, 20 ml/min). Detection was at 210 nm (KNAUER, “Smartline” UV detector 2500). The collected IS fraction from the HPLC was completely dried. Mixtures of steviol glycosides (SVglys) containing IS could be purified over SPE cartridges without change of the SVgly over IS ratio. The calibration curves for rebaudioside A (RebA) and stevioside (ST) were linear between 0.012 and 0.95 and between 0.013 and 1.13 mM for RebA and ST, respectively. The accuracy was checked by the standard addition method. It was concluded that the IS method gives an excellent precision and accuracy.
文摘A novel stability indicating reverse phase ultra performance liquid chromatographic (UP-LC) method has been developed for Etravirine along with eight impurities (imp-1, imp-2, imp-3, imp-4, imp-5, imp-6, imp-7 and imp-8) and validated as per ICH recommendations. Stress degradation conditions were established for Etravirine by subjecting it to stress conditions of acid, base, oxidation, humidity, thermal and photolysis. Significant degradation is observed in base stress condition and the major degradant (RRT at about 0.94) is identified by LC-MS and spectral analysis. The stress samples were assayed against a qualified reference standard and the mass balance was found close to 99.0%. Efficient chromatographic separation was achieved on a Shimpack ODS-II stationary phase with a gradient mobile phase combination. Quantification was carried at 303 nm at a flow rate of 0.6 mL?min–1. The resolution between Etravirine and eight potential impurities is found to be greater than 2.0. Regression analysis shows as r value (correlation coefficient) of greater than 0.999 for Etravirine and eight potential impurities. This method is capable to detect the impurities of Etravirine at a level of 0.003% with respect to test concentration of 1.0 mg·mL–1.
文摘Degradation pathway for pitavastatin calcium is established as per ICH recommendations by validated and stability indicating reverse phase liquid chromatographic method. Pitavastatin is subjected to stress conditions of acid, base, oxidation, thermal and photolysis. Significant degradation is observed in acid and base stress conditions. Four impurities are studied among which impurity-4 is found prominent degradant. The stress samples are assayed against a qualified reference standard and the mass balance is found close to 99.5%. Efficient chromatographic separation is achieved on a BEH C18 stationary phase with simple mobile phase combination delivered in gradient mode and quantification is carried at 245 nm at a flow rate of 0.3 mL min-1. In the developed UPLC method the resolution between pitavastatin calcium and four potential impurities is found to be greater than 4.0. Regression analysis shows an r value (correlation coefficient) of greater than 0.998 for pitavastatin calcium and four potential impurities. This method is capable to detect the impurities of pitavastatin calcium at a level of 0.006% with respect to test concentration of 0.10 mg/mL for a 2-μL injection volume. The developed UPLC method is validated with respect to specificity, linearity & range, accuracy, precision and robustness for impurities determination and assay determination.
文摘Degradation pathway for gefitinib is established as per ICH recommendations by validated and stability in-dicating reverse phase liquid chromatographic method. Gefitinib is subjected to stress conditions of acid, base, oxidation, thermal and photolysis. Significant degradation is observed in acid and base stress condi-tions. Two impurities are studied among which one impurity is found prominent degradant. The stress sam-ples are assayed against a qualified reference standard and the mass balance is found close to 99.5%. Effi-cient chromatographic separation is achieved on a Agilent make XDB-C18, 50 × 4.6 mm with 1.8 μm parti-cles stationary phase with simple mobile phase combination delivered in gradient mode and quantification is carried at 250 nm at a flow rate of 0.5 mL?min-1. In the developed RPLC method the resolution between ge-fitinib and the potential impurities is found to be greater than 5.0. Regression analysis shows an r value (cor-relation coefficient) of greater than 0.998 for gefitinib and the two potential impurities. This method is capa-ble to detect the impurities of gefitinib at a level of 0.01% with respect to test concentration of 0.5 mg?mL-1 for a 4-μL injection volume. The developed RRLC method is validated with respect to specificity, linearity & range, accuracy, precision and robustness for impurities determination and assay determination.
文摘A simple, precise and accurate high performance thin layer chromatographic method has been developed for the simultaneous estimation of Isotretinoin and Erythromycin in pharmaceutical gel. The separation was carried out on Merck TLC aluminum sheets of silica gel 60 F254, (20 × 10 cm) with 250 μm thickness using toluene: DMSO: methanol (6.5:0.2:2.5, v/v/v) as a mobile phase. HPTLC separation of the two drugs followed by densitometric measurement of their spots at 340 nm for Isotretinoin before derivatization and 410 nm for Erythromycin after derivatization with 10% H2SO4 and heating at 100°C for 15 min. The drugs were satisfactorily resolved with RF values of 0.38 ± 0.02 and 0.55 ± 0.02 for Isotretinoin and Erythromycin, respectively. The accuracy and reliability of the method was assessed by evaluation of linearity (30-150 ng spot-1 for Isotretinoin and 1200-6000 ng spot-1 for Erythromycin), precision (intra-day RSD 0.62-0.79% and inter-day RSD 0.43-0.71 % for Isotretinoin and intra-day RSD 0.47-1.71 % and inter-day RSD 0.42-1.49 % for Erythromycin), accuracy (98.91 ± 0.92 % for Isotretinoin and 99.27 ± 0.72 % for Erythromycin), and specificity, in accordance with ICH guidelines.
文摘A simple efficient isocratic reversed-phase HPLC method was developed and validated for the determination of clindamycin palmitate hydrochloride (CPH) and its commercially available oral solution products. Separation was achieved on a Phenomenex Zorbax (Luna) cyano column (150 × 4.6 mm, 5 μm) with a Phenomenex cyano guard cartridge (4 × 3.0 mm) on Agilent 1050 series HPLC system. CPH and its resolution standard lincomycin were eluted isocratically at a flow rate of 1 mL/min with a simplified mobile phase (potassium phosphate buffer (5 mM, pH 3.0)—acetonitrile—tetrahydrofuran (20:75:5, v/v/v)) and detected at 210 nm. The column was maintained at 25?C. The method was validated according to USP category I requirements. Robustness and forced degradation studies were also conducted. CPH marketed drug products were obtained from a drug distributor and assayed for potency using the validated method. Validation acceptance criteria were met in all cases. The analytical range for CPH was 15 - 500 μg/mL and the linearity was r2 > 0.999 over three days. The method was determined to be specific and robust. Both accuracy (92.0% - 103.8%) and precision (0.67% - 1.52%) were established across the analytical range for low, intermediate and high QC concentrations. Method applicability was demonstrated by analyzing two marketed products of CPH, in which results showed potency >98%. The method was determined to be an enhancement over the current USP methodology for assay as a result of increased efficiency, reduced organic solvents and the elimination of matrix modifiers. This method was successfully applied for the quality assessment of: 1) currently marketed drug products and 2) will in future assess the product quality of novel dosage forms of CPH for pediatric use.
文摘ABSTRACT A simple, economic, and time-efficient related substance, GC method has been developed for the analysis of 1,4-Cyclohexanedione mono- ethylene ketal(will be specified as ketal) in the presence of a potential impurity 1,4-cyclohexa- nedione bis (ethylene ketal) [will be specified as diketal]. Successful chromatographic separa- tion of the ketal from the impurity was achieved on a DBWAX ETR, 30 m x 0.32 mm x 1.0μ FT column with nitrogen as carrier gas and FID detector. The method was validated for linearity, accuracy, precision, and specificity and can be used for quality control during manufacture of ketal. A validated GC method is reported for the ketal for the first time.