ABSTRACT
Colon specific drug delivery system has attracted considerable attention for the past few years in order to develop drug delivery systems that are able to release drugs specifically in the colon in a predictable and reproducible manner. The colon is a site where both local and systemic delivery of drugs can take place. To achieve successful colon targeted drug delivery, a drug need to be protected from degradation, release and absorption in the upper portion of the gastric intestinal tract (GIT) and then to be ensured abrupt or controlled release in the proximal colon. This review is aimed at understanding recent approaches for dosage forms which is targeting to colon through pH sensitive system, microbially triggered system i.e., prodrugs and polysaccharide based system, timed release system, osmotically controlled drug system, pressure dependent release system.
ABSTRACT
Salbutamol sulphate (SS) loaded microspheres were prepared by solvent evaporation method with combination of hydroxy propyl methyl cellulose and Carbopol polymers in various proportions. A total of eleven formulations were prepared i.e. E1, E2, E3, E4, E5, E6, E7, E8, E9, E10 and E11.The particle size of all the formulations were ranged between 110±0.02 and 183±0.02μm. The entrapment efficiency was ranged between 68.3±0.01 and 94.9±0.02%. Based on above parameters four formulations were selected i.e. E5, E8, E9 and E10 for further studies like micromeretic properties, swelling index and in-vitro release profile. It was confirmed with the results of micromeretic property that all the selected formulations showed good flow property. Release data were analyzed based on Highuchi kinetics and Korsmeyer-Peppas equation and all the selected formulations showed good fit to Highuchi model. Stability studies showed almost negligible changes in particle size, entrapment efficiency and drug release throughout the study period.
ABSTRACT
The aim of the present study was formulate and clinically evaluate 5-fluorouracil (5-FU) transdermal patches. Cytotoxicity was measured by exposing cell suspensions to increasing concentrations of drug from 10-100 microg/ml and performing viable cell counts by the trypan blue exclusion method. Results confirmed 100 infinity g/ml and 50 microg/ ml of 5-FU to be cytotoxic to EAC and DLA cells. In mice, increase in the life span (ILS) by 87.1% with a maximum survival time of 30.5+/-1.87 days was found with EAC cell-induced tumors, with an ILS of 88.1% and a maximum survival time of 39.5+/-1.87 days for DLA cell-induced lesions with 5-FU transdermal patches. The results were statistically significant (p<0.01) compared to untreated controls. Pharmacokinetic studies in rabbits showed a t1/2 of 29+/-6 min, a Cmax (ng/ml) of 978.23, an AUC0-infinity (ng/ml/h) of 1213.73 +/-14 and a Tmax (h) of 0.5. 5-FU from transdermal patches exhibited a half-life of 95+/-0.5 min, a Cmax (ng/ml) of 863.25, an AUC0-infinity (ng/ml/h) of 1567+/-36 and a Tmax (h) of 1.5. Velcro protection jackets proved suitable in this study to stop mice licking, scratching and rubbing applied patches.