SOLUBILITY AND DISSOLUTION RATE ENHANCEMENT OF TELMISARTAN BY SOLID DISPERSION AND PELLETIZATION TECHNIQUES USING KOLLIDON VA 64 AS CARRIER

Objective: In the present investigation, an attempt was made to improve the surface characters and solubility of the drug by solid dispersion and coating it on the nonpareil sugar beads as pellets. Methods: Telmisartan solid dispersions were prepared by solvent evaporation technique using Kollidon VA64 as binder and solubility enhancer, Crospovidone as disintegrant and ethanol was used as the solvent. Telmisartan pellets were prepared by dissolving telmisartan, kollidonVA64, Crospovidone in ethanol in different ratios and coated on nonpareil sugar beads as a drug layer by pan coating technique. All the formulations were further evaluated for physicochemical parameters such as particle size, friability, angle of repose and drug content. In vitro dissolution studies were carried out in pH 7.5 phosphate buffer by using USP apparatus II. Results: It was observed that the dissolution rate of the solid dispersion formulation TSD5 showed a better dissolution rate to the extent of 1.113 folds and 1.979 folds when compared to a marketed formulation and pure drug, respectively. Similarly, the formulation TPL3containing 1:3 ratio of Telmisartan to Kollidon VA64 showed an improved dissolution rate to the extent of 1.150 folds and 2.045 folds when compared to the marketed formulation and pure drug, respectively. Majority of the formulations displayed first-order release kinetics and were found to be linear with R2 values in the range of 0.905 to 0.994. FTIR analysis and DSC analysis revealed that there was no major interaction between the drug and the excipients used in the design of the formulation. SEM analysis was performed for solid dispersions, pellet formulations and its polymers to determine the surface characteristics. Conclusion: From the present study, it was observed that the solubility of Telmisartan was enhanced by Kollidon VA 64 in pellet formulations when compared to solid dispersions

Direct synthesis of 2-(cycloalkylamino)-3,4-substituted thiophenes via selective deprotonation-cyclization of aroyl ketene N,S-acetals

Acyclic and cyclic aroyl ketene N,S-acetals undergo regioselective deprotonation-cyclization via dipole stabilized carbanion in the presence of LDA/THF to afford the corresponding 2-(cycloalkylamino)-4-aryl or 3,4-annelated thiophenes in moderate to good yields

Synthesis and anti–microbial activity of 1,2,3–triazole tethered nitroguiacol ethers

Nitro aromatic/nitrophenols have been widely distributed in nature and are mostly isolated from marine microorganisms and had shown a broad spectrum of anti–microbial activities against a wide range of microbial pathogens. The objective of the present work is to Synthesize some new 1,2,3–triazole tethered nitroguiacol ethers and evaluated of their anti–bacterial and anti–fungal activities. A focused library of 1,2,3-triazole tethered nitroguiacol ethers were prepared by employing Cu (I) catalyzed click chemistry reaction and evaluated for their antimicrobial activities by broth microdilution method. Among the tested compounds, compounds 8e, 8f, 8g, and 8i exhibited broad–spectrum activity against selected pathogenic strains, with the MIC of 8 µg/mL for gram–positive bacteria (Staphylococcus aureus), 16 µg/mL for Pseudomonas aeruginosa (gram–negative bacteria), and Candida species, respectively. Future investigations with this class of compounds may lead to the development of potential candidates for antimicrobial drug discovery.Â

ESTIMATION OF PRIMIDONE IN COMMERCIAL DOSAGE FORMS USING A SIMPLE AND CONVENIENT HPLC METHOD

ABSTRACT A simple fast and precise reverse phase high performance liquid chromatographic method has been developed for the determination of Primidone Tablets. A symmetry (5µ, 150 x 4 .6mm column) in isocratic mode with methanol: Water (50:50) as mobile phase. The Flow rate is1.0ml/min and effluent is monitored at 210nm

Purification and characterization of a thermostable glucoamylase from the thermophilic fungus Thermomyces lanuginosus.

Glucoamylase (1,4-alpha-D-glucan glucohydrolase, EC 3.2.1.3) was purified from the culture filtrates of the thermophilic fungus Thermomyces lanuginosus and was established to be homogeneous by a number of criteria. The enzyme was a glycoprotein with an average molecular weight of about 57 000 and a carbohydrate content of 10-12%. The enzyme hydrolysed successive glucose residues from the non-reducing ends of the starch molecule. It did not exhibit any glucosyltransferase activity. The enzyme appeared to hydrolyse maltotriose by the multi-chain mechanism. The enzyme was unable to hydrolyse 1,6-alpha-D-glucosidic linkages of isomaltose and dextran. It was optimally active at 70 degrees C. The enzyme exhibited increase in the Vmax. and decreased in Km values with increasing chain length of the substrate molecule. The enzyme was inhibited by the substrate analogue D-glucono-delta-lactone in a non-competitive manner. The enzyme inhibited remarkable resistance towards chemical and thermal denaturation

Thermal stabilization of glucose oxidase and glucoamylase by physical entrapment

Physical entrapment was used as an approach to achieve thermal stabilization of enzymes. The ti values for the thermoinactivation of glucose oxidase and glucoamylase were increased several-fold by their entrapment in polyacrylamide gels. In polyacrylate gels the individual enzymes behaved differently, probably owing to microenvironmental effects arising by the polyelectrolyte nature of the carrier