Dinesh R. Shah

Antiurolithiatic activity of saponin rich fraction from the fruits of Solanum xanthocarpum Schrad. & Wendl. (Solanaceae) against ethylene glycol induced urolithiasis in rats

ETHNOPHARMACOLOGICAL RELEVANCE A well-known traditional herb Solanum xanthocarpum is widely used in India for the management of different ailments including urolithiasis. This study was designed to rationalize the use of Solanum xanthocarpum in kidney stone and to investigate its mechanism of action. MATERIALS AND METHODS The saponin rich fraction prepared from fruits of Solanum xanthocarpum (SXS) was evaluated for antiurolithiatic activity by in vitro and in vivo studies. In ethylene glycol (EG, 0.75% in drinking water for 28 days) induced urolithiasis model, two different experimental doses (20 mg/kg and 40 mg/kg, p.o., for 28 days) of saponin rich fraction were selected by dose fixation study. After 28 days, various biochemical parameters were measured in urine, serum and kidney homogenate. Kidneys were also subjected to histopathological analysis. RESULTS In vitro calcium oxalate crystal (CaOx) nucleation as well as aggregation was inhibited in artificial urine solution by SXS. The lithogenic treatment caused polyuria, damage renal function and oxidative stress, manifested as increased malondialdehyde, depleted reduced glutathione and decreased antioxidant enzyme catalase activities of the kidneys, which were prevented by simultaneous administration with SXS. Lithogenic treatment also caused crystalluria, hyperoxaluria, hypercalciuria, hypocitrauria, and hypomagnesaemia. Deposition of CaOx in renal tissue and cellular injury were seen in histopathology. Co-administration of SXS had potential to prevent these pathological changes due to lithogenic treatment. Moreover, SXS raised level of glycosaminoglycan, a stone inhibitor macromolecule found in urine which decreased. CONCLUSION The antiurolithiatic activity in Solanum xanthocarpum is mediated possibly through the inhibition of CaOx crystal formation and its effect on the urinary concentration of stone-forming constituents and nephrolithiasis inducing factors and this study rationalizes its medicinal use in urolithiasis.

Protective effect of aqueous extract of Oroxylum indicum Linn. (root bark) against DNBS-induced colitis in rats.

Objective: Aqueous root extract of Oroxylum indicum was evaluated in rats against dinitrobenzene sulfonic acid (DNBS) induced colitis. Materials and Methods: Rats were pre-treated orally for seven days and continued for four days after the induction of colitis with OIaq (100, 200, and 400 mg/kg) or vehicle. Colitis was induced by intracolonic instillation of 25 mg of DNBS per rat dissolved in 50% alcohol and 4 days later, the colonic mucosal damage was analyzed along with food intake, body weight, colon weight, spleen weight, histological damage, myeloperoxidase (MPO) activity, malondialdehyde (MDA) levels, reduced glutathione (GSH), and nitric oxide levels in colonic tissue homogenate. Results: Significant reduction in gross damage area, weight loss and increase in colonic and spleen weight were evident in test substance-pretreated animals’ dose dependently as compared to vehicle treated control. These effects were confirmed biochemically by a reduction in colonic myeloperoxidase activity, malondialdehyde levels, nitric oxide levels, and increase in reduced glutathione (GSH) levels. Furthermore, microscopic examination revealed diminution of inflammatory cell infiltration and submucosal edema in colon segments of rats treated with OIaq. Conclusion: The results demonstrate the protective effect of OIaq in the animal model of acute colitis possibly through an antioxidant, anti-lipoperoxidative or due to reduction in nitric oxide generation.

Chitosan–pectin polyelectrolyte complex as a carrier for colon targeted drug delivery

OBJECTIVE The objective of present work was to prepare a polyelectrolyte complex (PEC) between chitosan (polycation) & pectin (polyanion) and to develop enteric coated tablets for colon delivery using the PEC. METHODOLOGY The PECs were prepared using different concentrations of chitosan and pectin. Drug loaded enteric coated tablets were prepared by wet granulation method using PEC to sustain the release at colon and coating was done with Eudragit S 100 to prevent the early release of the drug in stomach and intestine. Two independent variable, % PEC (chitosan/pectin) and % coating were optimized by 3(2) full factorial design. Statistical model were also used to supplement the optimization. DSC was performed to confirm the interaction between the polyions. Developed formulations were evaluated for physical appearance, weight variation, thickness, hardness, friability, % swelling, assay, in-vitro and ex-vivo drug release studies to investigate the PECs ability to deliver the drug to colon. Ex-vivo release study using rat caecal content was also carried out on optimized formulation. RESULTS AND DISCUSSION DSC results confirmed chitosan/pectin interaction and subsequent formation of PEC. The optimized formulation containing 1.1% of PEC and 3% of coating showed highest swelling and release in alkaline pH mechanism of which was found to be microbial enzyme dependent degradation established by ex-vivo study using rat caecal content.

Formulation development of Carvedilol compression coated tablet

Purpose: The aim of present research was to produce carvedilol compression coated tablet to provide biphasic drug release. Method: A compressed coated tablet made of a sustained release core tablet and an immediate release coat tablet. Both the core and the coat contained carvedilol. The sustained release effect was achieved with polymers (HPMC K4M and PEO WSR 205) to modulate the release of the drug. The powder blends for core and coat tablets were evaluated for angle of repose, bulk density, compressibility index, and drug content. Compressed coated tablets were evaluated for thickness, diameter, weight variation test, drug content, hardness, friability, disintegration and in vitro release studies. Result: The powder blends showed satisfactory flow properties, compressibility, drug content and all the tablet formulations showed acceptable pharmaco-technical properties. Carvedilol contained in the fast releasing component was released within 3 min, whereas the drug in the core tablet was released at different times up to 24 h, depending on the composition of the matrix tablet. The mechanism of drug release was fickian diffusion or anomalous behavior. Discussion: Batch F7, containing 10 mg PEO WSR 205 and 5 mg HPMC K4M, showed maximum similarity with theoretical profile and zero order drug release kinetic.

Effect of Boerhaavia diffusa in experimental prostatic hyperplasia in rats

Objective: Present investigation was undertaken to study the effectiveness of hydroalcoholic extract of roots of Boerhaavia diffusa in experimental benign prostatic hyperplasia (BPH) in rats using various animal models. Materials and Methods: BPH in rats was induced by subcutaneous injection of testosterone (5 mg/kg) daily for 28 days. Rats were divided in to five groups (six rats each). A negative control group received arachis oil (1 ml/kg s.c.) and four groups were injected testosterone. These four groups were further divided into reference group (finasteride 1 mg/kg), model group (testosterone), study group A (B. diffusa 100 mg/kg), and study group B (B. diffusa 250 mg/kg). On the 29th day, rats were sacrificed and body weight, prostate weight, bladder weight, and serum testosterone level were measured and histological studies were carried out. Further in vitro analysis of B. diffusa extract on contractility of isolated rat vas deferens and prostate gland, produced by exogenously administered agonists were carried out. All results were expressed as mean ± SEM. 0 Data were analyzed by one-way analysis of variance followed by Tukeys test. Results: B. diffusa (100 mg/kg) treatment for 28 days resulted in significant inhibition of prostate growth (P < 0.05). Drug extract did not have significant change on serum testosterone level. Histopathological analysis of prostate gland supported above results. Results of in vitro experiment suggest that extracts had attenuated the contractile responses of isolated vas deferens and prostate gland to exogenously applied agonists. Conclusion: The results suggested that treatment with B. diffusa may improve symptoms of disease and inhibit the increased prostate size. In vitro study implies that herbal extracts has the machinery to produce beneficial effect on prostatic smooth muscle, which would relieve the urinary symptoms of disease. B. diffusa could be a potential source of new treatment of prostatic hyperplasia.

Formulation and optimization of ethosomes for transdermal delivery of ropinirole hydrochloride.

The present study focuses on the formulation of ethosomal gel of ropinirole hydrochloride (ropinirole HCl), an anti-Parkinsonian drug, for delivery as a carrier for transdermal application. The ethosomes were prepared using different concentrations of phospholipids (2-5 % w/v), ethanol (20-50 % w/v), ropinirole HCl (5 % w/v) and water. They were optimized using 3(2) full factorial designs to study the effect of independent variables, concentrations of ethanol and lecithin on dependent variables, entrapment efficiency and in-vitro drug release at 24 hrs. The drug release profile exhibited Higuchis and zero order kinetics. From the regression analysis, it was observed that independent variables had significant effect on response variables. Formulations were optimized using contour plot and response surface plot. The optimized formulation was found to be RS10 containing 30 % w/v ethanol and 4% w/v lecithin. The optimized formulation was evaluated for assay, particle characteristics, zeta potential, skin retention and stability. Ethosomal gel was prepared by incorporation of optimized ethosomal suspension into gel base. The ethosomal gel was characterized for physical appearance, pH, content uniformity, rheological behaviour, skin-retention, in-vitro and in-vivo drug release and stability. From the results it can fairly be concluded that ethosomes are capable of delivering ropinirole hydrochloride into systemic circulation by transdermal route. The amounts thus delivered are also equitable to those delivered orally and are delivered at a rate slow enough to achieve longer blood levels.

Development of Controlled Release Osmotic Pump Tablet of Glipizide Solid Dispersion

PURPOSE To develop controlled release osmotic pump tablets (COPT) of glipizide (GZ) solid dispersion (SD). METHODS In elementary osmotic pump (EOP) tablets, an osmotic core with the drug is surrounded by a semi-permeable membrane which is drilled with a delivery orifice. COPT tablets eliminate the need of drilling process as controlled release can be achieved by the presence of osmogen in the coating. Poorly water soluble drug molecule cannot give satisfactory drug release hence GZ solid dispersion was prepared in the present study. The SDs having different ratio of drug to Poloxamer (PXM) 188 were prepared by hot melt method and optimized by solubility study, drug content estimation and in vitro dissolution study. Effect of two independent variables, amount of osmogen (potassium chloride) and hydrophilic polymer (polyethylene oxide WSR 303), were investigated using 3(2) factorial design. Core and coated tablets were evaluated for pharmacotechnical parameters. In-vitro drug release profiles of COPT tablets were compared with marketed with push-pull osmotic pump tablet, Glucotrol XL. RESULTS Prepared core and coated tablets showed acceptable pharmacotechnical parameters. Drug release was directly proportional to initial level of hydrophilic polymer, but inversely related to the osmogen, confirming osmotic mechanism. Zero order drug release pattern was achieved which was comparable to marketed product. CONCLUSION Novel oral controlled release of glipizide was successfully achieved by incorporating glipizide solid dispersion into osmotic system.

Development and validation of dissolution method for carvedilol compression-coated tablets

The present study describes the development and validation of a dissolution method for carvedilol compression-coated tablets. Dissolution test was performed using a TDT-06T dissolution apparatus. Based on the physiological conditions of the body, 0.1N hydrochloric acid was used as dissolution medium and release was monitored for 2 hours to verify the immediate release pattern of the drug in acidic pH, followed by pH 6.8 in citric-phosphate buffer for 22 hours, to simulate a sustained release pattern in the intestine. Influences of rotation speed and surfactant concentration in medium were evaluated. Samples were analysed by validated UV visible spectrophotometric method at 286 nm. 1% sodium lauryl sulphate (SLS) was found to be optimum for improving carvedilol solubility in pH 6.8 citric-phosphate buffer. Analysis of variance showed no significant difference between the results obtained at 50 and 100 rpm. The discriminating dissolution method was successfully developed for carvedilol compression-coated tablets. The conditions that allowed dissolution determination were USP type I apparatus at 100 rpm, containing 1000 ml of 0.1N HCl for 2 hours, followed by pH 6.8 citric-phosphate buffer with 1% SLS for 22 hours at 37.0 ± 0.5 oC. Samples were analysed by UV spectrophotometric method and validated as per ICH guidelines.

Formulation and In Vivo Hypoglycemic Effect of Glipizide Solid Dispersion

The present study was carried out with a view to enhance dissolution rate of poorly water-soluble drug glipizide (GZ) (BCS class II) using polyethylene glycol (PEG) 6000, PEG 8000 and poloxamer (PXM) 188 as carriers. Solid dispersions (SDs) were prepared by melting method using different ratios of glipizide to carriers. Phase solubility study was conducted to evaluate the effect of carrier on aqueous solubility of glipizide. SD was optimized by drug content estimation and in vitro dissolution study and optimised SD was subjected to bulk characterization, Scanning electron microscopy (SEM), Fourier transformation infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC) and X-ray diffraction study (XRD). Preclinical study was performed in mice to study the decrease in blood glucose level from prepared SD compared with pure drug. Due to high solubility and drug release, PXM 188 in weight ratio of 1:2 was optimized. Decrease in blood glucose level in mice from SD was significantly higher (p < 0.05) compared to pure glipizide. Thus, solid dispersion technique can be successfully used for the improvement of the dissolution profile of GZ.

Kinetic Determinations of Pitavastatin Calcium by Stability Indicating HPTLC Method

A simple, sensitive, precise, and stability-indicating high-performance thin-layer chromatographic method has been developed and validated for the quantitative determination of pitavastatin calcium (PTV) in a pharmaceutical dosage form in the presence of its degradation products. The stability of PTV was investigated under different stress conditions, including hydrolytic, oxidative, photolytic, and thermal, as recommended by the International Conference on Harmonization guidelines. PTV was separated on aluminum-backed silica gel 60 F254 high-performance thin-layer chromatography (HPTLC) plates as a stationary phase with ethyl acetate–methanol–toluene–glacial acetic acid (4:1:5:0.1, v/v/v/v) as a mobile phase. Regression analysis data for the calibration plots were indicative of good linear relationships between responses and concentration over the range 25–150 ng per band. The method was validated for linearity, precision, accuracy, robustness, specificity, and sensitivity. The drug was subjected to stress degradation and peaks of all the degradation products were well resolved from that of the pure drug, with significantly different Rf value, which indicates the specificity and stability-indicating properties of the method. The kinetic determination was evaluated in acid conditions. The acid degradation of PTV showed an apparent first-order kinetics and rate constants were found to be 0.00202 µg/mL/min in 0.1 N HCl at 75°C.