Progress in experimental models to investigate the in vivo and in vitro antidiabetic activity of drugs

Diabetes mellitus is one of the world's most prevalent and complex metabolic disorders,and it is a rapidly growing global public health issue.It is characterized by hyperglycemia,a condition involving a high blood glucose level brought on by deficiencies in insulin secretion,decreased activity of insulin,or both.Prolonged effects of diabetes include cardiovascular problems,retinopathy,neuropathy,nephropathy,and vascular alterations in both macro-and micro-blood vessels.In vivo and in vitro models have always been important for investigating and characterizing disease pathogenesis,identifying targets,and reviewing novel treatment options and medications.Fully understanding these models is crucial for the researchers so this review summarizes the different experimental in vivo and in vitro model options used to study diabetes and its consequences.The most popular in vivo studies involves the small animal models,such as rodent models,chemically induced diabetogens like streptozotocin and alloxan,and the possibility of deleting or overexpressing a specific gene by knockout and transgenic technologies on these animals.Other models include virally induced models,diet/nutrition induced diabetic animals,surgically induced models or pancreatectomy models,and non-obese models.Large animals or non-rodent models like porcine(pig),canine(dog),nonhuman primate,and Zebrafish models are also outlined.The in vitro models discussed are murine and human beta-cell lines and pancreatic islets,human stem cells,and organoid cultures.The other enzymatic in vitro tests to assess diabetes include assay of amylase inhibition and inhibition ofα-glucosidase activity.

Design,delivery and efficacy testing of therapeutic nucleic acids used to inhibit hepatitis C virus gene expression in vitro and in vivo

Despite major achievements in the treatment ofchronic hepatitis C with the combination ofinterferons and the nucleoside analog ribavirin themajority of patients with chronic hepatitis C virus(HCV) infection cannot be treated effectively.Toimprove this response rate we used antisensetechnologies to inhibit HCV translation as possibleadditional option for experimental treatment.Antisense oligodeoxynucleotides(ODN) are

Double-layered osmotic pump controlled release tablets of actarit: In vitro and in vivo evaluation

The aim of the study was to develop actarit double-layered osmotic pump tablets to overcome the weak points of actarit common tablets, such as short half-life and large plasma concentration fluctuations. Single factor experiment and orthogonal test were applied to optimize the formulation;the pharmacokinetic study was performed in beagle dogs adopting actarit common tablets as reference tablets. The optimal formulation was as follows: drug layer: 150 mg actarit, 240 mg PEO-N80, 50 mg NaCl;push layer: 140 mg PEO-WSR303, 20 mg NaCl;coating solution: 30 g cellulose acetate and 6 g PEG 4000 in 1000 ml 94% acetone solution, 60 mg coating weight gain. The pharmacokinetic study showed that T max was prolonged by the contrast of commercial common tablets with constant drug release rate, but the bioavailability was equivalent. And a good in vivo –in vitro correlation of the actarit osmotic pump tablets was also established. The designed actarit osmotic pump tablets can be applied for rheumatoid arthritis, proposing a promising replacement for the marked common products.

Insight into the preformed albumin corona on in vitro and in vivo performances of albumin-selective nanoparticles

Preformed albumin corona of albumin-nonselective nanoparticles(NPs)is widely exploited to inhibit the unavoidable protein adsorption upon intravenous administration.However,very few studies have concerned the preformed albumin corona of albumin-selective NPs.Herein,we report a novel type of albumin-selective NPs by decorating 6-maleimidocaproyl polyethylene glycol stearate(SA)onto PLGA NPs(SP NPs)surface,taking albuminnonselective PLGA NPs as control.PLGA NPs and SP NPs were prepared by emulsion-solvent evaporation method and the resultant NPs were in spherical shape with an average diameter around 180 nm.The corresponding albumin-coating PLGA NPs(PLGA@BSA NPs)and albumin-coating SP NPs(SP@BSA NPs)were formulated by incubating SP NPs or PLGA NPs with bovine serum albumin solution,respectively.The impact of albumin corona on particle characteristics,stability,photothermal effect,cytotoxicity,cell uptake,spheroid penetration and pharmacokinetics was investigated.In line with previous findings of preformed albumin coating,PLGA@BSA NPs exhibited higher stability,cytotoxicity,cell internalization and spheroid penetration performances in vitro,and longer blood circulation time in vivo than those of albumin-nonselective PLGA NPs,but albumin-selective SP NPs is capable of achieving a comparable in vitro and in vivo performances with both SP@BSA NPs and PLGA@BSA NPs.Our results demonstrate that SA decorated albumin-selective NPs pave a versatile avenue for optimizing nanoparticulate delivery without preformed albumin corona.

Development of cryptotanshinone-loaded pellets for angina chronotherapy:In vitro/in vivo prediction and evaluation

The clinical manifestations of variant angina is unevenly distributed during the 24 h, thusthe in vivo performance of drugs should be tailored according to the angina circadianrhythm. Cryptotanshinone(CTN) is one of the representative bioactive lipid-soluble com-ponents of Danshen which has been commonly used for cardiovascular diseases such asangina pectoris. The aim of this study was to develop a novel CTN sustained-released pel-lets(CTN-SRPs) to precisely synchronize the CTN plasma concentrations with predictedoccurrence of angina pectoris for angina chronotherapy. A deconvolution-based methodwas applied to develop and optimize the CTN-SRPs. The plasma concentration-time curveof CTN immediate-released formulation after oral administration in rats was used as theweight function. The predicted plasma concentration-time curve of CTN-SRPs simulatedaccording to the incidence of variant angina during 24 h was used as the response func-tion. Then the desired drug release profile of CTN-SRPs was calculated based on deconvo-lution using weight function and response function, and subsequently used for guiding theformulation optimization. CTN-SRPs were prepared with the combinations of PVP, polox-amer 127 and EC as matrix using fluidized bed technology. An orthogonal design was em-ployed to obtain the optimal formulation with its release profile similar with the desiredone. Pharmacokinetic studies validated that the actual plasma concentration-time curve ofthese optimized CTN-SRPs was similar with the predicted one. In addition, the percent er-rors(%PE) of CTN plasma concentrations in 8–12 h were less than 10%. In conclusion, thisdeconvolution-based method could be applied to adjust the in vivo performance of drugs forangina chronotherapy.

The antitumor effect of bromophenol derivatives in vitro and Leathesia nana extract in vivo

To investigate the antitumor effect of bromophenol derivatives in vitro and Leathesia nana extract in vivo, six bromophenol derivatives 6-（2,3-dibromo-4,5-dihydroxybenzyl）-2,3-dibromo-4,5-dihydroxy benzyl methyl ether （1）, （＋）-3-（2,3-dibromo-4,5-dihydroxyphenyl）-4-bromo-5,6-dihydroxy-1,3- dihydroisobenzofuran （2）, 3-bromo-4-（2,3-dibromo-4,5-dihydroxybenzyl）-5-methoxymethyl-pyrocatechol （3）, 2,2＇,3,3＇-tetrabromo-4,4＇,5,5＇-tetrahydroxy-diphenylmethane （4）, bis（2,3-dibromo-4,5-dihydroxybenzyl） ether （5）, 2,2＇,3-tribromo-3＇,4,4＇,5-tetrahydroxy-6＇-ethyloxymethyldiphenylmethane （6） were isolated from brown alga Leathesia nana, and their cytotoxicity were tested by MTF assays in human cancer cell lines A549, BGC-823, MCF-7, B16-BL6, HT-1080, A2780, Be17402 and HCT-8. Their inhibitory activity against protein tyrosine kinase （PTK） with over-expression of c-kit was analyzed also by ELISA. The antitumor activity of ethanolic extraction of Leathesia nana （EELN） was evaluated on S180-bearing mice. All compounds showed very potent cytotoxicity against all of the eight cancer cell lines with IC50 below 10 pg/mL. In PTK inhibition study, all bromophenol derivatives showed moderate inhibitory activity and compounds 2, 5 and 6 showed significant bioactivity with the inhibition ratio of 77.5%, 80.1% and 71.4% respectively. Pharmacological studies reveal that EELN could inhibit the growth of Sarcoma 180 tumor and increase the indices of thymus and spleen to improve the immune system remarkably in vivo. Results indicated that the bromophenol derivatives and EELN can be used as potent antitumor agents for PTK over-expression of c-kit and considered in a new therapeutic strategy for treatment of cancer.

Sustained release donepezil loaded PLGA microspheres for injection:Preparation,in vitro and in vivo study

The purpose of this study was to develop a PLGA microspheres-based donepezil(DP)formulation which was expected to sustain release of DP for one week with high encapsulation efficiency(EE).DP derived from donepezil hydrochloride was encapsulated in PLGA microspheres by the O/W emulsion-solvent evaporation method.The optimized formulation which avoided the crushing of microspheres during the preparation process was characterized in terms of particle size,morphology,drug loading and EE,physical state of DP in the matrix and in vitro and in vivo release behavior.DP microspheres were prepared successfully with average diameter of 30m,drug loading of 15.92±0.31%and EE up to 78.79±2.56%.Scanning electron microscope image showed it has integrated spherical shape with no drug crystal and porous on its surface.Differential scanning calorimetry and X-ray diffraction results suggested DP was in amorphous state or molecularly dispersed in microspheres.The Tg of PLGA was increased with the addition of DP.The release profile in vitro was characterized with slow but continuous release that lasted for about one week and fitted well with first-order model,which suggested the diffusion governing release mechanism.After single-dose administration of DP microspheres via subcutaneous injection in rats,the plasma concentration of DP reached peak concentration at 0.50 d,and then declined gradually,but was still detectable at 15 d.A good correlation between in vitro and in vivo data was obtained.The results suggest the potential use of DP microspheres for treatment of Alzheimer’s disease over long periods.

In vitro-in vivo studies on anti-trypanosomal potentials of Zapoteca portoricensis

Objective:Aqueous extracts of Zapoteca portoricensis are used traditionally as antidiarrhea agent and in the treatment of diverse gastrointestinal disorders here in Nigeria specifically,the southern part.Similarly,the aqueous extract of the plant is also used traditionally as anticonvulsant,antispasmodic and in the treatment of tonsillitis.Recently too,the anti-inflammatory and antimicrobial activities of the methanol extracts of the root of Zapoteca portoricensis was reported.In this research,we are set to investigate the trypanocidal activity of Zapoteca portoricensis.Methods:The methanol extract of the root of Zapoteca portoricensis was investigated for both in vitro and in vivo trypanocidal activity following established models.In summary,phytochemical analysis was carried out on both the crude powdered root and on the methanol extract following standard procedures. The oral acute toxicity test(LD50 ) of the crude methanol extract was determined according to the method described by Lorke（1983）.Albino mice（17g-21g） of either sex were used.The methanol extract was suspended in 3%v/v tween 85 and administered orally at doses of 10 mg/kg,100 mg/kg and 1 000 mg/kg to three groups of mice（n = 3 ）.The animals were observed for 24 hours.Based on the result obtained in this initial test,doses of 4 mg/kg,6 mg/kg,and 8 mg/kg were administered to three different mice.The LD50 was calculated as the geometric mean of the lowest dose killing a mouse and the highest dose showing no death.The invivo /in-vitro antitrypanosomal evaluations were carried out in experimental animals and tissue cell culture respectively. Results:The result of the in vitro studies shows the inhibitive concentration-50（IC-50） against Trypanosoma brucei rhodesiense（T.b.rhodesiense） to be 0.372 mg/kg,while the control drug melarsoprol was 0.006 mg/kg.On Trypanosoma brucei brucei（T.cruzi）,the IC-50 is 6.42 mg/kg against 0.87 of the reference drug Benznidazole.The cytotoxicity on L-6 cells exhibited an IC-50 of 0.039 6 mg/kg against the reference drug,podophyllotoxin of 0.01 mg/kg.However,the in vivo study shows that the extract,at the administered doses,could not exhibit appreciable reduction of parasitemia and hence resulted to the death of test animals. Conclusion:The present data suggests that Zapoteca portoricensis could yield useful leads for the development of potentially potent antitrypanocides.

Application of custom anatomy-based nerve conduits on rabbit sciatic nerve defects: in vitro and in vivo evaluations

The intermingling of regenerated nerve fibers inside nerve grafts is the main reason for mismatched nerve fibers. This is one of the key factors affecting limb function recovery after nerve injury. Previous research has shown that the accuracy of axon regeneration can be improved by a bionic structural implant. To this aim, iodine and freeze-drying high-resolution micro-computed tomography was performed to visualize the 3D topography of the New Zealand rabbit sciatic nerve (25 mm). A series of 1-, 2-, 3-, and 4-custom anatomy-based nerve conduits (CANCs) were fabricated based on the anatomical structure of the nerve fascicle. The match index, luminal surface, and mechanical properties of CANCs were evaluated before implanting in a 10-mm gap of the sciatic nerve. Recovery was evaluated by histomorphometric analyses, electrophysiological study, gastrocnemius muscle weight recovery ratio, and behavioral assessments at 12 and 24 weeks postoperatively. The accuracy of nerve regeneration was determined by changes in fluorescence-labeled profile number during simultaneous retrograde tracing. Our results showed that the optimal preprocessing condition for high-resolution micro-computed tomography visualization was treatment of the sciatic nerve with 40% Lugol’s solution for 3 days followed by lyophilization for 2 days. In vitro experiments demonstrated that the match index was highest in the 3-CANC group, followed by the 2-, 1-, and 4-CANC groups. The luminal surface was lowest in the 1-CANC group. Mechanical properties (transverse compressive and bending properties) were higher in the 3- and 4-CANC groups than in the 1-CANC group. In vivo experiments demonstrated that the recovery (morphology of regenerated fibers, compound muscle action potential, gastrocnemius muscle weight recovery ratio, pain-related autotomy behaviors, and range of motion) in the 3-CANC group was superior to the other CANC groups, and achieved the same therapeutic effect as the autograft. The simultaneous retrograde tracing results showed that the percentages of double-labeled profiles of the 2-, 3-, and 4-CANC groups were comparatively lower than that of the 1-CANC group, which indicates that regenerated nerve fascicles were less intermingled in the 2-, 3-, and 4-CANC groups. These findings demonstrate that the visualization of the rabbit sciatic nerve can be achieved by iodine and freeze-drying high-resolution micro-computed tomography, and that this method can be used to design CANCs with different channels that are based on the anatomical structure of the nerve. Compared with the 1-CANC, 3-CANC had a higher match index and luminal surface, and improved the accuracy of nerve regeneration by limiting the intermingling of the regenerated fascicles. All procedures were approved by the Animal Care and Use Committee, Xinjiang Medical University, China on April 4, 2017 (ethics approval No. IACUC20170315-02).

Effects of Size and Surface Charge of Polymeric Nanoparticles on in Vitro and in Vivo Applications

Biodegradable polymeric materials are the most common carriers for use in drug delivery systems. With this trend, newer drug delivery systems using targeted and controlled release polymeric nanoparticles (NPs) are being developed to manipulate their navigation in complex in vivo environment. However, a clear understanding of the interactions between biological systems and these nanoparticulates is still unexplored. Different studies have been performed to correlate the physicochemical properties of polymeric NPs with the biological responses. Size and surface charge are the two fundamental physicochemical properties that provide a key direction to design an effective NP formulation. In this critical review, our goal is to provide a brief overview on the influences of size and surface charge of different polymeric NPs in vitro and to highlight the challenges involved with in vivo trials.

Protective effects of Ecklonia cava extract on the toxicity and oxidative stress induced by hair dye in in-vitro and in-vivo models

Oxidative hair dyes containingρ-phenylenediamine(PPD)are reported to induce an allergic reaction by promoting oxidative stress when absorbed through the skin.Despite the associated risk,these hair dyes remain popular owing to their convenience and sharpness of color.This makes it important to minimize the cytotoxicity and oxidative stress induced by PPD-containing hair dyes.Ecklonia cava extract has been evaluated in different studies for its protective effects against external stress in fibroblasts and keratinocytes.Our study was aimed at using in-vitro and in-vivo models to investigate the extract’s effects on cytotoxicity of and oxidative stress induced by PPD-containing hair dyes.Analysis of CIEL*a*b*Color space was first used to determine the range of E.cava extract that would not interfere with the coloring ability of the dye upon addition.Subsequently,the set ranges of E.cava extract(5% and 7%)were added to the hair dye and their toxicity assessed by evaluating the viability of fibroblasts and keratinocytes.The effects on developmental phenotypes and induction of oxidative stress by hair dye were evaluated and compared with those of hair dyes containing different contents of E.cava extract using an in-vivo zebrafish model.Our results showed that E.cava extract in hair dye could significantly decrease the cytotoxicity and levels of oxidative stress caused by hair dyes containing PPD in both in-vitro and in-vivo models.These results suggest that the addition of 7% E.cava extract to 250μg/mL hair dye does not interfere with the coloring ability of the dye while showing significant protective eff ects against the hair dye.The study proposes that the use of E.cava extract as an adduct to hair dyes containing PPD reduces the cytotoxicity and oxidative stress induced by these hair dyes.

Gan Shen Fu Fang ameliorates liver fibrosis in vitro and in vivo by inhibiting the inflammatory response and extracellular signalregulated kinase phosphorylation

BACKGROUND Liver fibrosis is a common health problem worldwide and there is still a lack of effective medicines.The Chinese herbal medicine,Gan Shen Fu Fang(GSFF)is composed of salvianolic acid B and diammonium glycyrrhizinate.In this study,we observed the effects of GSFF on liver fibrosis in vivo and in vitro in an attempt to provide some hope for the treatment.AIM To observe the effects of GSFF on liver fibrosis in vivo and in vitro and investigate the mechanism from the perspective of the inflammatory response and extracellular signal-regulated kinase(ERK)phosphorylation.METHODS Common bile duct-ligated rats were used for in vivo experiments.Hepatic stellate cells-T6(HSC-T6)cells were used for in vitro experiments.Hematoxylin and eosin staining and Masson staining,biochemical assays,hydroxyproline(Hyp)assays,enzyme-linked immunoasorbent assay and western blotting were performed to evaluate the degree of liver fibrosis,liver function,the inflammatory response and ERK phosphorylation.The CCK8 assay,immunofluorescence and western blotting were applied to test the effect of GSFF on HSC-T6 cell activation and determine whether GSFF had an effect on ERK phosphorylation in HSC-T6 cells.RESULTS GSFF improved liver function and inhibited liver fibrosis in common bile ductligated rats after 3 wk of treatment,as demonstrated by histological changes,hydroxyproline assays and collagen I concentrations.GSFF alleviated inflammatory cell infiltration and reduced the synthesis of pro-inflammatory cytokines[tumor necrosis factor-α(TNF-α)and interlukin-1β]and NF-κB.In addition,GSFF decreased ERK phosphorylation.In vitro,GSFF inhibited the viability of HSC-T6 cells with and without transforming growth factorβ1(TGF-β1)stimulation and decreased the synthesis of collagen I.GSFF had the greatest effect at a concentration of 0.5μmol/L.GSFF inhibited the expression ofα-smooth muscle actin(α-SMA),a marker of HSC activation,in HSC-T6 cells.Consistent with the in vivo results,GSFF also inhibited the phosphorylation of ERK and downregulated the expression of NF-κB.CONCLUSION GSFF inhibited liver fibrosis progression in vivo and HSC-T6 cell activation in vitro.These effects may be related to an alleviated inflammatory response and downregulated ERK phosphorylation.

Formation of Superoxide Radical and Hydrogen Peroxide Enhanced by Trinitrotoluene in Rat Liver, Brain, Kidney, and Testicle in Vitro and Monkey Liver in Vivo

Trinitrotoluene (TNT) increased the formation of adrenochrome from adrenaline and the formation of formaldehyde from methanol in rat liver mitochondria and microsomes in vitro as well as in monkey liver mitrochondria and microsomes in vivo. The effects were more prominent at higher TNT concentrations. These findings indicate that TNT enhances the production of superoxide radicals (O_2^-) and hydrogen peroxide (H_2O_2). The production of O_2^- was more prominent in systems containing added TNT than in those containing added benzyl viologen. H_2O_2 production by mitochondria was more pronounced in the liver than in other organs, but its production by microsomes was more pronounced in the brain than in other organs. The results suggest that TNT undergoes cycling reduction which produces oxidative stress. 1989 Academic Press, Inc.

The Effect of a Dietary Supplement Spirulina and Bifidobacterium adolescentis on the Cholesterol-Lowering in Vitro and in Vivo

The survey＇s results showed a significant percentage of women and especially men having an above normal cholesterol. In order to help reduce excessive rate of blood cholesterol, we used a local strain of Spirulina （Tamanrasset, in south of Algeria） associated with probiotic bacteria （Bf adolescentis）. Experiments in vitro showed a significant degradation of total cholesterol by the combination of Spirulina and Bf adolescentis （74.5%） after 72 hours incubation at 37 ~C. A cholesterol is added to the standard diet mice in order to increase the total cholesterol for three lots. However, the rates of total cholesterol in mice receiving lower fermented milk with Bf adolescentis enriched by dry Spirulina. This shows that the decrease of cholesterol rate is closely related to the presence of Bf adolescentis and Spirulina. In vitro and in vivo results show, however, that it is possible to obtain a natural product （Spirulina） and a pseudo-strain lactic （Bf adolescentis） and to participate in the prevention of cardiovascular disease risk factor whose hand is cholesterol.

THE SPECIFIC PHOTODYNAMIC EFFECTS OF MONOCLONAL ANTIBODIES CONJUGATED WITH HEMATOPORPHYRIN DERIVATIVE ON GASTRIC CANCER IN VITRO AND IN VIVO

Murine monoclonal antibody (MoAb) BB4.3, raised against the human gastric cancer cell line BGC823, was puriffied with Protein A-Sepharose CL-4B affinity chromatography and identified as IgG2a. It was then conjugated with a hematoporphyrin derivative (HPD) by using carbodiimide. The qualitative analysis of this conjugate showed that the amount of free HPD was negligible and there were no IgG aggregates among the conjugates. The conjugate retained both the antibody and photochemical activity of HPD.In vitro, the phototoxic effect of this HPD-BB4.3 conjugate on target cells was about 15 times higher than that of free HPD. The quality of selective photocytotoxicity was proven by the greater cytotoxi-city this conjugate showed than that of corresponding normal mouse IgG (NIgG) conjugated with HPD. It showed less cytotoxicity to colon cancer cell line B-80 (negative reaction to MoAb BB4.3) than to BGC825. Moreover, its cytotoxicity to BGC823 cells could be blocked specifically by excess BB4.3 antibody, but not by another MoAb 3G9, which combines with BGC823 at different binding sites from MoAb BB4.3.Nude mice inoculated with 2 × 10- BGC823 cells were given HPD-BB4.3, HPD, HPD-NIgG, HPD plus BB4.3 and PBS, respectively then exposed to light. Four out of six animals treated with the HPD-BB4.3 conjugate remained tumor-free for a long period. Although two developed tumors, there was a significant difference between the HPD-BB4.3-treated group and all the control groups in tumor induction time, tumor growth rate, and survival time (p<0.001). The HPD-BB4.3 conjugate inhibited the growth of established tumors by more than 40% in comparison with control groups (p<0.05).

Genetic Diversity of Intragenomic Rearrangement of Porcine Circovirus Type 2 in vitro and in vivo

We characterized the genome sequences of defective-interfering(DI) particle DNA of porcine circovirus type 2(PCV2) by sequencing and bioinformatics analyses. DI particles were both generated by serial passage of PCV2 in PK15 cells and obtained from sera of pigs with postweaning multisystemic wasting syndrome(PMWS). These subviral isolates ranged from 358 nt to 1 125 nt genomes. Investigating the complexity and diversity of PCV2 DI in vivo and in vitro can help elucidating the evolutionary history of PCV2.

Systematically optimized topical delivery system for Loperamide hydrochloride: Formulation design,in vitro and in vivo biopharmaceutical evaluation

This study aimed to develop a suitable topical delivery system containing diethylene glycol monoethyl ether(DGME) for Loperamide hydrochloride(Lop). Two factors, three levels CentralComposite design were applied by generating a quadratic polynomial equation to form contour plots and response surface for prediction of responses as two selected independent variables with EtOH-DGME ratio and EtOH concentration. The response variables flux and skin retention were determined in in vitro hairless mouse skin model. The selected optimum formulation was evaluated for the skin transport characteristics by developing dermatokinetic analysis model and the results demonstrated DGME improved the delivery of Lop into skin deep layers, which was further confirmed by confocal laser scanning microscopy(CLSM)study. In vitro skin permeation was found to have triphasic correlation with plasma AUC in the in vivo pharmacokinetic study. The in vitro–in vivo correlation enabled the prediction of pharmacokinetic profile of Lop from in vitro permeation results. Therefore, the optimum formulation capable of enhancing Lop intracutaneous depot could be a candidate for topical delivery of Lop as analgesics.

Plant Regeneration of Ziziphus spina-christi by in vivo and in vitro Methods

Christ's thorn (Ziziphus spina-christi L. Desf.) is ecologically and economically important in Iran. Since it is a cross-pollinated plant with a wide range of genetic variability, an investigation was carried out to determine the best method for mass and clonal propagation. Three vegetative methods were examined, including 1) cutting, where shoots with a 22-25 cm length and three shoot diameters were treated with two culture media; 2) layering, where air layering and trench layering treatments consisted of three growth regulators at three levels of concentration; and 3) tissue culture with nodal segments bearing axillary buds that were removed from shoots of mature trees at different seasons. Several experiments were carried out to determine the best disinfectant chemical, the best culture method, the best season, the appropriate explant characteristics and media type. Rooting was successful only on the sandy beds for cuttings with more than (S.O mm diameter. For the trench layering method, only one specimen in one replicate rooted a very small root, while for the air layering method, only seedlings with growth regulator treatments rooted successfully. The best season for explant harvesting was determined as mid summer, and among the disinfecting treatments, Ca(OCI)2 at a concentration of 0 5 g kg-1 for 20 minutes was the best. There were no significant differences for shoot weight and length with a Murashige and Skoog (MS) medium with and without a hormone.

Design and comparative in-vitro and in-vivo evaluation of starch-acrylate graft copolymer based salbutamol sulphate sustained release tablets

The present work deals with the development of controlled release tablets of salbutamol sulphate(SS)using graft copolymers of methyl methacrylate(St-g-PMMA and Ast-g-PMMA)on starch and acetylated starch.Formulations were evaluated for physical characteristics like hardness,friability,drug release,drug content and weight variations,which fulfilled all the official requirements of tablet dosage form.The release rates from formulated matrix tablets were studied at SGF(pH 1.2)followed by SIF(pH 6.8).Drug release from the graft copolymer based tablets was found to be sustained upto the 14 h with>75%drug release.The in-vitro release study showed that the graft copolymer based matrix formulations(F3&F4)exhibited highest correlation value(r2)for higuchi kinetic model and Korsmeyer's model with n values between 0.61 and 0.67 proved that release mechanisms were governed by both diffusion and erosion mechanism.There was no significant difference in the pharmacokinetic parameters(tmax,Cmax,AUC,Ke,and t1/2)of the graft copolymers matrices and HPMC K100M matrix tablets,indicating their comparable sustained release effect.The potential of graft copolymers to sustain the drug release is well supported by in-vivo pharmacokinetic studies and their adequate physicochemical properties make them promising excipients for controlled drug delivery system.