A validated LC method for the quantitative determination of celecoxib in pharmaceutical dosage forms and purity evaluation in bulk drugs

A new reversed-phase, isocratic LC method was developed for the quantitative determination of COX-2 inhibitor celecoxib in bulk drugs and in pharmaceutical dosages. The proposed method is also applicable for the purity evaluation of celecoxib in bulk drugs. 5-Methyl 2-Nitro phenol has been used as internal standard for the quantitative determination of celecoxib. The method has been completely validated and proven to be rugged. The limit of detection (LOD) and limit of quantitation (LOQ) for celecoxib impurities namely, 4-hydrazino benzene sulfonamide (Intermediate I) and 1-(4-methyl phenyl)-4,4.4-trifluro butan-1,3-dione (Intermediate II) were found to be 32.0 and 97 ng. respectively. The active pharmaceutical ingredient was extracted from its finished dosage form (capsule) using methanol. The percentage recoveries ranged from 90.7 to 93.8. The stability studies were performed for celecoxib solution placed on laboratory bench and in refrigerator for hundred days. The samples were found to be stable for the study period.

LC method for the quantitative determination of oxaprozin and its impurities in the bulk drug

A reversed phase linear gradient liquid chromatographic method was developed for the separation and quantitative determination of the seven known process related impurities and one degraded product of oxaprozin in the bulk drug material. An Inertsil-ODS 3V (150 x 4.6 mm), 5 microm column was operated with a phosphate buffer acetonitrile gradient. Detection was carried out on a UV detector at 254 nm. This method has been proved to be accurate and sensitive. The limits of detection (LOD) and limits of quantification (LOQ) of impurities were in the order of 5-60 ng and 16-200 ng, respectively. In addition to its ruggedness and robustness, this method offers identification of all eight impurities in a single run.

LC method for the determination of assay and purity of sibutramine hydrochloride and its enantiomers by chiral chromatography

Two isocratic liquid chromatography (LC) methods have been developed for the purity estimation and quantitative determination of sibutramine HCl, using 4-chloro aniline and lovastatin as internal standards, respectively. The precision has been checked in terms of F-test variance ratio using latter method as reference. The ratio of variances of the two methods is close to unity, confirming their good precision. The correlation coefficient for linear regression is more than 0.999. The inter and intra-day precision is found to be < 1.3% RSD. The accuracy determined as relative mean error (RME) for the intra-day assay is +/- 1.7%. The enantiomeric separation of sibutramine by chiral chromatography method has been described also. This method is capable of separating the two enantiomers with a selectivity of 1.4 and a resolution of 4.0. Both methods are found to be stability indicating and useful in the quality control of the bulk material.

A validated method for the determination and purity evaluation of benazepril hydrochloride in bulk and in pharmaceutical dosage forms by liquid chromatography

A gradient liquid chromatographic (LC) method has been developed for the determination and purity evaluation of benazepril hydrochloride in bulk and pharmaceutical dosage forms. The method is simple, rapid and selective. 5-Methyl-2-nitro phenol has been used as internal standard. The method is linear in the range of 50-800 microg. The precision for inter and intra-day assay variation of benazepril hydrochloride is below 1.6% RSD. The accuracy determined as relative mean error (RME) for the intra-day assay is within +/- 2.0%. The method is stability indicating, and is useful in the quality control of bulk manufacturing and also in pharmaceutical formulations.

Butyrolactones from Aspergillus terreus

In the process development of lovastatin using Aspergillus terreus DRCC 152 in solid state fermentation, we have isolated a new butyrolactone-IV (3) along with the previously reported butyrolactone-I (1) and butyrolactone-II (2) produced under submerged conditions. The structure of compound 3 has been characterized as 3-hydroxy-5-[2-(1-hydroxy-1-methylethyl)-2(R)-2,3-dihydro-benzo[b]furan- 5 ylmethyl]-4-(4-hydroxyphenyl)-5-methoxycarbonyl-(5R)-2,5-dihydro-2 -furanone on the basis of spectroscopic studies. The absolute stereochemistry has been determined by single crystal X-ray diffraction studies. The cytotoxic and antibacterial activities of these compounds were determined.

Troglitazone, an euglycemic antidiabetic drug

Troglitazone (or 5-{4-[(6-hydroxy-2,5,7,8-tetramethyl-chroman-2-yl) methoxy]benzyl}thiazolidine-2,4-dione, C24H27NO5S) is the first euglycemic drug. The molecules are held together in the lattice by intermolecular hydrogen bonds between the hydroxy O atom of the chroman moiety, and the ketone O and ring N atom of the thiazolidine-2,4-dione moiety.

Synthesis and biological activity of novel thiazolidinediones

Novel compounds having a dual pharmacophore were synthesised and evaluated for their insulin sensitiser and anti-inflammatory properties in different animal models.