Rapid and selective assay of clozapine in human plasma using high performance liquid chromatography and ultraviolet detection

Arapid high performance liquid chromatographic method has been developed for the determination of clozapine in human plasma. A simple extraction step with acetonitrile was done. The analysis was performed on a C[18] [3.9 x 150 rnm] reversed phase analytical column with the wavelength fixed at 280 nm. The mobile phase consisted of methanol-water-triethylamine, 70:30:0.05 [v:v:v], flowing at a rate of 0.6 ml/minute, using celecoxib as an internal standard. Calibration curves were linear in the range of 10-300 ng/ml and the lower detection limit was 5 ng/ml. The intra-assay and inter-assay precision as well as recovery and reproducibility values were satisfactory. The developed method was used to compare between two commercially available products of clozapine in 24 healthy volunteers

Influence of gelucires and rhodopases on sustainment of in -domethacin via solid dispersions

Solid dispersions of indomethacin in different release retarding materials; namely, Gelucire 50/02 and Gelucire 50/13, Rhodopas M and Rhodopas H were prepared by fusion and coprecipitation methods, respectively. Solid dispersions were compressed into tablets where both physical parameters and dissolution were studied. The effect of various release retardants on anti-inflammatory characteristic of indomethacin adopting rat paw edema and ulcerogenicity on rat stomach from the most appropriate preparations reached were done. A satisfactory prolongation of drug dissolution from its tablets made with Gelucires was obtained from drug tablets containing 10% w/w of Gelucire 50/02. However, drug tablets prepared with 2.5% of the same polymer showed a shorter retardation time. The percentage of drug release was decreased by increasing the percentage of Gelucire 50/02. In contrast, the increasing Gelucire 50/13 concentration caused a remarkable increase in drug release from its tablets. On the other h and, indomethacin tablets prepared with Rhodopases M and H showed a remarkable protraction of the drug release. The greatest protraction was obtained with 6% Rhodopas H that was too excessive to attain a reasonable level

Microencapsulation of indomethacin using different polymers

Indomethacin microcapsules were prepared with three different polymers; namely, ethyl cellulose 100[EC], Eudragit RSPM [Eud] and sodium carboxymethylcellulose [Na CMC] using solvent-evaporation technique with the first two polymers and coacervation-phase separation by electrolyte addition technique with the latter. Kollidon K-25 was used as a channeling agent. All the prepared microcapsules were subjected to drug content determination, microscopical examination, particle size analysis and drug release studies. The anti- inflammatory characteristic adopting rat paw edema method and ulcerogenicity in terms of ulcer index on rat stomach of indomethacin from the most appropriate preparation reached were studied