Fast and sensitive LC–MS/MS method for the simultaneous determination of lisinopril and hydrochlorothiazide in human plasma

A sensitive and rapid liquid chromatography-tandem mass spectrometry(LC–MS/MS) method has been developed for the simultaneous determination of lisinopril(LIS) and hydrochlorothiazide(HCTZ) in human plasma using their labeled internal standards(ISs). Sample pre-treatment involved solid phase extraction on Waters Oasis HLB cartridges using 100 μL of plasma, followed by liquid chromatography on Hypersil Gold C_(18)(50 mm×3.0 mm, 5 μm) column. The analytes were eluted within 2.0 min using acetonitrile-5.0 m M ammonium formate, p H 4.5(85:15, v/v) as the mobile phase. The analytes and ISs were analyzed in the negative ionization mode and quantified using multiple reaction monitoring. The method showed excellent linearity over the concentration range of 0.50–250.0 ng/m L for both the analytes. The intra-batch and inter-batch precision(% CV) was ≤5.26% and their extraction recoveries were in the range of 96.6%–103.1%. Matrix effect evaluated in terms of IS-normalized matrix factors ranged from 0.97 to 1.03 for both the analytes. The validated method was successfully applied to determine the plasma concentration of the drugs using 10 mg lisinopril and 12.5 mg hydrochlorothiazide fixed dose formulation in 18 healthy Indian volunteers.

Simultaneous determination of amlodipine,valsartan and hydrochlorothiazide by LC-ESIMS/MS and its application to pharmacokinetics in rats

Polypill is a fixed-dose combination that contains three or more active ingredients used as a single daily pill to achieve a large effect in preventing cardiovascular disease with minimal adverse effects.A novel and accurate liquid chromatography tandem mass spectrometry method using electrospray ionization mode has been developed and validated for the simultaneous determination of amlodipine（AMD）,valsartan（VAL） using losartan（LOS） as an internal standard（IS）,and hydrochlorothiazide（HCT） using furosemide（FSD） as an IS.The separation was carried on Aquasil C18（50 mm×2.1 mm,5μm） reversed phase column using acetonitrile and water containing 0.1%formic acid（50：50,v/v） as the mobile phase.The method was validated in terms of linearity,accuracy and precision over the concentration range of 1-1000 ng/mL.The intra and inter-day precision and accuracy,stability and extraction recoveries of all the analytes were in the acceptable range.This method can be successfully applied to the pharmacokinetic study of AMD,VAL and HCT when given as a polypill.

Simultaneous determination of captopril and hydrochlorothiazide by time-resolved chemiluminescence with artificial neural network calibration

The combined use of chemometrics and chemiluminescence（CL）measurements,with the aid of the stopped-flow mixing technique,developed a simple time-resolved CL method for the simultaneous determination of captopril（CPL）and hydrochlorothiazide（HCT）.The stopped-flow technique in a continuous-flow system was employed in this work in order to emphasize the kinetic differences between the two analytes in cerium（IV）-rhodamine 6G CL system.After the flow was stopped,an initial rise of CL signal was observed for HCT standards,while a direct decay of CL signal was obtained for CPL standards.The mixed CL signal was monitored and recorded on the whole process of continuous-flow/stopped-flow,and the obtained data were processed by the chemometric approach of artificial neural network.The relative prediction error（RPE）of CPL and HCT was 5.9% and 8.7%,respectively.The recoveries of CPL and HCT in tablets were found to fall in the range between 95% and 106%.The proposed method was successfully applied to the simultaneous determination of CPL and HCT in a compound pharmaceutical formulation.

Application of an LC–MS/MS method for the analysis of amlodipine,valsartan and hydrochlorothiazide in polypill for a bioequivalence study

A sensitive and selective method has been proposed for the simultaneous determination of amlodipine(AML),valsartan(VAL) and hydrochlorothiazide(HCTZ) in human plasma by liquid chromatography–tandem mass spectrometry(LC–MS/MS). The analytes and their deuterated analogs were quantitatively extracted from100 μL human plasma by solid phase extraction on Oasis HLB cartridges. The chromatographic separation of the analytes was achieved on a Chromolith RP18 e(100 mm × 4.6 mm) analytical column within 2.5 min. The resolution factor between AML and VAL, AML and HCTZ, and VAL and HCTZ was 2.9, 1.5 and 1.4, respectively,under isocratic conditions. The method was validated over a dynamic concentration range of 0.02–20.0 ng/m L for AML, 5.00–10,000 ng/m L for VAL and 0.20–200 ng/m L for HCTZ. Ion-suppression/enhancement effects were investigated by post-column infusion technique. The mean IS-normalized matrix factors for AML, VAL and HCTZ were 0.992, 0.994 and 0.998, respectively. The intra-batch and inter-batch precision(% CV) across quality control levels was ≤ 5.56% and the recovery was in the range of 93.4%–99.6% for all the analytes. The method was successfully applied to a bioequivalence study of 5 mg AML + 160 mg VAL + 12.5 mg HCTZ tablet formulation(test and reference) in 18 healthy Indian males under fasting. The mean log-transformed ratios of C max, AUC0–120 h and AUC0-inf and their 90% CIs were within 90.2%–102.1%. The assay reproducibility was demonstrated by reanalysis of 90 incurred samples.

Advancing USP compendial methods for fixed dose combinations: A case study of metoprolol tartrate and hydrochlorothiazide tablets

The current United States Pharmacopeia–National Formulary(USP–NF) includes more than 250 monographs of fixed dose combinations(FDCs), and some of them need to be updated due to incompleteness of impurity profiles and obsolescence of analytical methodologies. A case study of metoprolol tartrate and hydrochlorothiazide tablets is presented to summarize challenges encountered during the USP monograph modernization initiative of FDCs and to highlight an "adoption and adaptation" approach employed for method development. To this end, a single stability-indicating HPLC method was developed to separate the two drug substances and eight related compounds with resolution 2.0 or higher between all critical pairs. Chromatographic separations were achieved on a Symmetry column(C18,100 mm*4.6 mm, 3.5 mm) using sodium phosphate buffer(pH 3.0; 34 mM) and acetonitrile as mobile phase in a gradient elution mode. The stability-indicating capability of this method has been demonstrated by analyzing stressed samples of the two drug substances. The developed HPLC method was validated for simultaneous determination of metoprolol tartrate and hydrochlorothiazide and relevant impurities in the tablets. Moreover, the developed method was successfully applied to the analysis of commercial tablet dosage forms and proved to be suitable for routine quality control use. The case study could be used to streamline USP's monograph modernization process of FDCs and strengthen compendial procedures.

Simultaneous quantification of amiloride and hydrochlorothiazide in human plasma by liquid chromatography–tandem mass spectrometry

A selective, sensitive and precise assay based on solid phase extraction and liquid chromatography–tandem mass spectrometry(LC–MS/MS) was developed for the simultaneous determination of amiloride(AMI) and hydrochlorothiazide(HCTZ) in human plasma. Sample clean-up with 250 μL of plasma was done on Phenomenex Strata^(?)-X extraction cartridges using their labeled internal standards(AMI-15 N3 and HCTZ-13 C,d2). Chromatography was performed on Hypersil Gold C18(50 mm×3.0 mm, 5 μm) column using acetonitrile with 4.0 m M ammonium formate(p H 4.0, adjusted with 0.1% formic acid)(80:20, v/v) as the mobile phase. Detection was carried out on a triple quadrupole API 5500 mass spectrometer utilizing an electrospray ionization interface and operating in the positive ionization mode for AMI and negative ionization mode for HCTZ. Multiple reaction monitoring was used following the transitions at m/z 230.6/116.0, m/z233.6/116.0, m/z 296.0/204.9 and m/z 299.0/205.9 for AMI, AMI-15 N3, HCTZ and HCTZ-13 C,d2,respectively. Calibration curves were linear(r2≥0.9997) over the concentration range of 0.050–50.0 and0.50–500 ng/m L for AMI and HCTZ, respectively, with acceptable accuracy and precision. The signal-to-noise ratio at the limit of quantitation was ≥14 for both the analytes. The mean recovery of AMI and HCTZ from plasma was 89.0% and 98.7%, respectively. The IS-normalized matrix factors determined for matrix effect ranged from 0.971 to 1.024 for both the analytes. The validated LC–MS/MS method was successfully applied to a bioequivalence study using 5 mg AMI and 50 mg HCTZ fixed dose tablet formulation in 18 healthy Indian volunteers with good reproducibility.

Development and Validation of HPLC Method for Simultaneous Determination of Amlodipine, Valsartan, Hydrochlorothiazide in Dosage Form and Spiked Human Plasma

A simple, sensitive, and specific method was developed for simultaneous determination of Amlodipine besylate (AML), Valsartan (Vals) and Hydrochlorothiazide (HCT) by high performance liquid chromatography without previous separation. Satisfactory resolution was achieved using a RP-C18 chromatographic column, Phenomenex Kinetex (150 mm × 4.6 mm i.d) and a mobile phase consisting of acetonitrile-phosphate buffer (0.05 M) with pH 2.8 in the proportion of (40/60, v/v) at a flow rate 0.8 mL/min and the wavelength detection was 227 nm. The retention time for HCT, AML and VAls was 2.26, 3.16 and 11.19 min;respectively. The described method was linear over a range of 4-28 μg /ml, 5-40 μg /ml and 1-12 μg /ml for AML, Vals and HCT;respectively. The mean percent recoveries were 99.94%, 99.96% and 99.78% for AML, Vals and HCT;respectively. F-test and t-test at 95%con?dence level were used to check the intermediate precision data obtained under different experimental setups. The method could be used for analysis of combined dose tablet formulation containing AML, Vals, HCT as well as spiked human plasma.

Pharmacokinetics of Hydrochlorothiazide, Losartan and E3174 after Oral Doses of Losartan and Losartan/Hydrochlorothiazide in Healthy Chinese Male Volunteers

Aims: A simple and highly sensitive LC-MS method was used to determine the concentrations of losartan, its major active metabolite E3174 and hydrochlorothiazide in human plasma and pharmacokinetic characteristics and metabolism phenotype observation after administration of losartan tablets and losartan/hydrochlorothiazide combination tablets. Methods: An open, randomized cross-over single-dose study was designed in forty healthy male volunteers, A single-dose of 50 mg losartan tablets or 50 mg losartan/12.5 mg hydrochlorothiazide combination tablets was orally given and blood samples were collected at scheduled time. A LC-MS method was established and evaluated for determining the plasma concentrations of losartan, E3174 and hydrochlorothiazide. The pharmacokinetic parameters and characteristic of metabolism phenotypes were calculated and compared via this test. Results: The elimination rate of E3174 (t1/2) was significantly shorter (P 0–t was lower (P 1/2, AUC0–t and AUC0–inf of E3174.

Rapid Simultaneous Determination of Olmesartan, —Amlodipine and Hydrochlorothiazide in Combined Pharmaceutical Dosage form by Stability-Indicating Ultra Performance Liquid Chromatography

A simple, precise and rapid stability-indicating ultra-performance liquid chromatography (UPLC) method was devel-oped for the simultaneous quantitative determination of Olmesartan, Amlodipine and Hydrochlorothiazide from their innovative Pharmaceutical combination drug product, with the presence of degradation products. It involved a 50 mm × 2.1 mm, 1.8 μm Phenyl column. The separation was achieved on simple gradient method. The mobile phase A contains a mixture of sodium perchlorate buffer pH 3.2(0.053M): acetonitrile in the ratio 90:10, v/v, and mobile phase B con- tains a mixture of sodium perchlorate buffer pH 3.2(0.053M): acetonitrile in the ratio 10:90, v/v. The flow rate was 0.7 mL?min–1 and column temperature was maintained at 55?C.The gradient program (T/%B) was set as 0/10, 2/50, 4/80, and 6.0/10. The detector wavelength was 271 nm for Hydrochlorothiazide, 215 for Olmesartan and 237 nm for Amlodipine. The retention times of Olmesartan, Amlodipine, and Hydrochlorothiazide are 3.5, 3.3 and 0.9 minutes;respectively. The total runtime was 6.0 minutes within which three active compounds and their degradation products were separated. The described method was validated with respect to system suitability, specificity, linearity, precision and accuracy. The precision of the assay method was evaluated by carrying out six independent assays of Olmesartan, Amlodipine, and Hydrochlorothiazide (0.004 mg?mL–1, 0.001 mg?mL–1, 0.0025 mg?mL–1). The accuracy of the method was evaluated in triplicate at three concentration levels, i.e. 50%, 100%, and 150% of target test concentration. The described method was linear over the range, 2 to 6 μg?mL–1 for Olmesartan, 0.5 to 1.5 μg?mL–1 Amlodipine and 1.25 to 3.75 μg?mL–1 for Hydrochlorothiazide. The method is fast and is suitable for high-throughput analysis of the drug and one can analyze about 240 samples per working day, facilitating the processing of large-number batch samples.

New simple spectrophotometric method for determination of the binary mixtures(atorvastatin calcium and ezetimibe;candesartan cilexetil and hydrochlorothiazide) in tablets

A new simple spectrophotometric method was developed for the determination of binary mixtures without prior separation.The method is based on the generation of ratio spectra of compound X by using a standard spectrum of compound Y as a divisor.The peak to trough amplitudes between two selected wavelengths in the ratio spectra are proportional to concentration of X without interference from Y.The method was demonstrated by determination of two drug combinations.The first consists of the two antihyperlipidemics：atorvastatin calcium（ATV） and ezetimibe（EZE）,and the second comprises the antihypertensives：candesartan cilexetil（CAN） and hydrochlorothiazide（HCT）.For mixture 1,ATV was determined using 10 μg/mL EZE as the divisor to generate the ratio spectra,and the peak to trough amplitudes between 231 and 276 nm were plotted against ATV concentration.Similarly,by using 10 μg/mL ATV as divisor,the peak to trough amplitudes between 231 and 276 nm were found proportional to EZE concentration.Calibration curves were linear in the range 2.5-40 mg/mL for both drugs.For mixture 2,divisor concentration was 7.5 μg/mL for both drugs.CAN was determined using its peak to trough amplitudes at 251 and 277 nm,while HCT was estimated using the amplitudes between 251 and 276 nm.The measured amplitudes were linearly correlated to concentration in the ranges 2.5-50 and 1-30 μg/mL for CAN and HCT,respectively.The proposed spectrophotometric method was validated and successfully applied for the assay of both drug combinations in several laboratory-prepared mixtures and commercial tablets.

Enalapril Combined with Hydrochlorothiazide and Indapamide in the Treatment of Hypertension with Heart Failure

Objecrive:To explore the effect of enalapril combined with hydroch1orothiazide and indapamide on hypertension and heart failure.Methods:8o patients with hypertension and heart failure admitted to our hospitail from January 2019 to January 2020 were selected as the research subjects,and they were divided into two groups with random number table method,40 cases each.The control group was given conventional treatment regimens,including enalapril and hydroch1orothiazide;the observation group replaced hydrochlorothiazide with indapamide based on the above therapies.The efficacy and systolic blood pressure,diastolic blood pressure and left heart ejection fraction(LVEF)of the two groups were compared.Results:After treatment,the effective rate of the observation group was 92.50%(37/40)higher than that of the control group 75.00%(30/40).The systolic and diastolic blood pressure were lower than those of the control group,and the LVEF was higher than that of the control group.The difference was statistically significant(P<0.05).Conclusion:Enalapril combined with indapamide is effective in the treatment of hypertension with heart failure,which can help 1ower blood pressure,reduce heart 1oad,increase cardiac output,reverse ventricular remodeling,and delay disease progression.

Determination of Candesartan and Hydrochlorothiazide in Human Plasma by HPLC Coupled with Mass Spectrometry

Quantitative determination of hydrochlorothiazide (HCTZ) and candesartan (CDS) in human plasma in volunteers was performed using a sensitive, selective and specific LC-MS method which has been developed and validated before the study. The study was performed by means of a liquid chromatograph Shimadzu Prominence equipped with a mass spectrometer LCMS-2020. Analytical column PerfectBond ODS-HD HPLC-column 5 μm 250 × 3.0 mm with a pre-column cartridge PerfectBond ODS-HD 5 μm 10 × 3.0 mm, double source of ionization for LCMS-2020 (electrospray (ESI) and chemical (APCI)) and software LabSol LCMS V5 LCMS2020 systempack were used. The low limit of the quantitative determination for HCTZ and CDS made up 10 ng/ml. m/z for CDS 441.20—positive scan, m/z for HCTZ 295.90—negative scan. The method has been applied to a pharmacokinetic study of 12.5 mg HCTZ and 16 mg CDS tablet in healthy volunteers.

Development and Validation of Bioanalytical Method for Determination of Telmisartan and Hydrochlorothiazide Using HPTLC in Human Plasma

A simple, sensitive, rapid and economic high performance thin layer chromatographic method has been developed for determination of telmisartan and hydrochlorothiazide in human plasma using paracetamol as an internal standard. The plasma sample was extracted using mixture of methanol-acetonitrile (3.0:0.1, v/v). A concentration range from 200, 400, 600, 800, 1000, 1200 ng/spots were used for calibration curve of hydrochlorothiazide and telmisartan respectively. The percent recovery of telmisartan and hydrochlorothiazide was found to be75.98 and 81.91%. The mobile phase consists of chloroform: methanol: toluene (8:2:4 v/v/v). Densitometric analysis was carried out at wavelength 278 nm. The Rf values for hydrochlorothiazide, paracetamol and telmisartan were 0.28 ± 0.05, 0.50 ± 0.05, 0.66 ± 0.05 respectively. The stability of telmisartan and hydrochlorothiazide in plasma were confirmed during three freeze-thaw cycles (?20?C), on bench during 24 hours and post preparative during 48 hours. The proposed method was validated statistically and by performing recovery study for determination of telmisartan and hydrochlorothiazide in human plasma.

Effect of irbesartan hydrochlorothiazide on endothelial function, hemodynamics and inflammatory response in hypertensive patients

Objective:To observe the effect of irbesartan hydrochloride on endothelial function, hemodynamics and inflammatory response in patients with essential hypertension.Method:A total of 100 patients with essential hypertension admitted from May 2015 to August 2017 in our hospital were divided into observation group (50 cases) and control group (50 cases) according to random number table. The control group was treated with routine treatment, and the observation group was treated with erbesartan hydrochlorothiazide on the basis of routine treatment in the control group. The changes of vascular endothelial function, hemodynamics and inflammatory factors in the two groups were compared.Results: Before treatment, there was no significant difference in vWF, EDD and NMD levels, hemodynamics level and CRP, ICAM-1 and MCP-1 levels. After treatment, the vWF level in the observation group was significantly decreased and the EDD level was significantly increased;while the level of NMD was not significantly changed. After treatment, the level of vWF in the control group was significantly decreased;but there was no significant change in EDD and NMD level. After treatment, vWF level (144.94±16.21)% in the observation group was significantly lower than that in the control group;EDD level (6.81±0.74)% was significantly higher than that in the control group. After treatment, the levels of LBV, HBV and PV in the observation group were significantly lower than those before treatment, while the levels of LBV, HBV and PV in the control group were not significantly different from those before treatment. After treatment, LBV level (13.34±1.41) m.pas, HBV level (5.13±1.34) m.pas and PV level (1.65±0.34) m.pas in the observation group were significantly lower than those in the control group. After treatment, the levels of CRP, ICAM-1 and MCP-1 in both groups were significantly lower than those before treatment. After treatment, the level of CRP (1.71±0.81) mg/L, ICAM-1 level (330.82±68.51) ng/mL and MCP-1 level (3.02±1.06) g/L in the observation group were significantly lower than those in the control group.Conclusion: Irbesartan hydrochlorothiazide treatment of hypertension can play a significant role in the improvement of vascular endothelial function and hemorheology in patients, and can significantly reduce the level of inflammatory response in the body, worthy of clinical application.

Stability Indicating RP-HPLC Method for Quantification of Impurities in Valsartan and Hydrochlorothiazide FDC Tablet Dosage Form

A stability-indicating RP-HPLC method has been developed and validated for simultaneous determination of Valsartan & Hydrochlorothiazide and their impurities in FDC (Fixed Dose Combination) tablet dosage form. The method was developed using L1 column (250 × 4.6 mm;5 μm) with gradient elution using the mobile phase consisting of solvent-A (0.1% Ortho phosphoric acid) and solvent-B (100% Acetonitrile);the gradient program (Tmin/%B) was set as 0/10, 5/10, 20/60, 40/60, 41/10 and 50/10. The eluted compounds were monitored at 265 nm. The developed method was validated as per ICH guidelines with respect to specificity, linearity, limit of detection, limit of quantitation, accuracy, precision and robustness. The influence of Acid, Alkaline, Oxidative, Photolytic, Thermal and Humidity stress conditions, on drug product was studied. The limit of quantification results of Valsartan, Hydrochlorothiazide and their impurities are, VAL: 0.303 μg/mL, HCTZ: 0.019 μg/mL, VAL RC-B: 0.085 μg/mL, VAL RC-C: 0.327 μg/mL, HCT RC-A: 0.017 μg/mL, CTZ: 0.080 μg/mL and 5-Chloro HCT: 0.047 μg/mL. The proposed method is suitable for the estimation of Valsartan & Hydrochlorothiazide impurities in tablets dosage form.

Acute kidney injury following autoimmune hemolytic anemia due to simultaneous use of ciprofloxacin and hydrochlorothiazide:A case report and review of the literature

Introduction:Rare cases of autoimmune hemolytic anemia(AHA)associated with using ciprofloxacin or hydrochlorothiazide(HCTZ)alone have been reported before.However,simultaneous use of both drugs could lead to a severe clinical condition.This study presents the combination of acute kidney injury(AKI)and AHA following the simultaneous use of ciprofloxacin and HCTZ for three days.Case Description:A 42-year-old Iranian woman presented to the emergency department with symptoms of fatigue,lethargy,nausea and vomiting,ataxia,oliguria,dark urine,and jaundice.The patient reported using HCTZ due to high blood pressure and ciprofloxacin for a urinary tract infection three days before presentation.Early laboratory findings revealed hemolytic anemia with a hemoglobin of 7 g/dl,the strongly positive direct and indirect Coombs test,high level of lactate dehydrogenase(820 IU/L),and hyperbilirubinemia(total:3 mg/dL and direct:1.2 mg/dL).Furthermore,hyperkalemia(5.2 mEq/L),hyperphosphatemia(6.2 mg/dL),high levels of BUN(100 mg/dL),and creatinine rise(6.8 mg/dL)were found.Urine analysis showed 2+blood,4-6 red blood cells,and cola-colored urine.Based on the findings,druginduced AHA,followed by AKI,was diagnosed.Following,the drugs were stopped and steroid therapy was initiated.The patient underwent four sessions of hemodialysis to improve the AKI.Conclusion:Healthcare providers should be aware of the life-threatening adverse effects of commonly used drugs such as ciprofloxacin or HCTZ.The timely diagnosis of the offending drugs leads to avoiding the persistence of the risk factor and the deterioration of the patient's clinical condition.

Efficacy and tolerability of a single-pill combination of telmisartan/ hydrochlorothiazide 80/25 mg in Chinese and Korean patients with moderate to severe hypertension： a subgroup analysis of a randomized, double-blind, active-controlled trial

Background Hypertension is an important issue in Asia, responsible for up to 66% of cardiovascular disease cases. This randomized controlled trial subgroup analysis compared telmisartan 80 mg （T80）/hydrochlorothiazide 25 mg （H25） single- pill combination with T80 monotherapy, specifically in Chinese and Korean patients.

Improved simultaneous quantitation of candesartan and hydrochlorthiazide in human plasma by UPLC–MS/MS and its application in bioequivalence studies

A validated ultra-performance liquid chromatography mass spectrometric method （UPLC-MS/MS） was used for the simultaneous quantitation of candesartan （CN） and hydrochlorothiazide （HCT） in human plasma. The analysis was performed on UPLC-MS/MS system using turbo ion spray interface. Negative ions were measured in multiple reaction monitoring （MRM） mode. The analytes were extracted using a liquid-liquid extraction （LLE） method by using 0.1 mL of plasma volume. The lower limit of quantitation for CN and HCT was 1.00 ng/mL whereas the upper limit of quantitation was 499.15 ng/mL and 601.61 ng/mL for CN and HCT respectively. CN d4 and HCT-13Cd2 were used as the internal standards for CN and HCT respectively. The chromatography was achieved within 2.0 min run time using a C18 Pheno-menex, Gemini NX （100 mm ~ 4.6 mm, 5 mm） column with organic mixture：buffer solution （80：20, v/v） at a flow rate of 0.800 mL/min. The method has been successfully applied to establish the bioequivalence of candesartan cilexetil （CNC） and HCT immediate release tablets with reference product in human subjects.

Development,characterization and solubility enhancement of comparative dissolution study of second generation of solid dispersions and microspheres for poorly water soluble drug

The poor dissolution characteristics of water-insoluble drugs are a major challenge for pharmaceutical scientists.Reduction of the particle size/increase in the surface area of the drug is a widely used and relatively simple method for increasing dissolution rates.The objective of this study was to improve solubility,release and comparability of dissolution of a poorly soluble drug using two different types of formulations(solid dispersions and microspheres).Hydrochlorothiazide was used as a model drug.The solid dispersions and microspheres were prepared by solvent evaporation method using ethyl cellulose,hydroxypropyl methylcellulose in different drug-to-carrier ratios(1:1,1:2 w:w).The prepared formulations were evaluated for interaction study by Fourier transform infrared spectroscopy,differential scanning calorimetry,percentage of practical yield,drug loading,surface morphology by scanning electron microscopy,optical microscopy and in-vitro release studies.The results showed no interaction between the drug and polymer,amorphous state of solid dispersions and microspheres,percentage yield of 42.53%to 78.10%,drug content of 99.60%to 99.64%,good spherical appearance in formulation VI and significant increase in the dissolution rate.