Prolonged release biodegradable vesicular carriers for rifampicin--formulation and kinetics of release.

An attempt has been made to design suitable liposome and niosome-encapsulated drug delivery system for rifampicin and evaluated the same in vitro and in vivo. A modified lipid layer hydration method was employed to prepare these vesicular carriers. The formulated systems were characterized in vitro for size distribution analysis, drug entrapment, drug release profiles and vesicular stability at different conditions of storage. In vivo drug kinetics was evaluated in normal, healthy albino rats for niosomal formulation upon subcutaneous injection and various pharmacokinetic parameters were determined. Niosomes and liposomes exhibited mean diameter of 9.73 and 11.87 microns with entrapment efficiencies of 30.5 and 34.2% respectively. Both the products exhibited sustained release characteristics in vitro with zero order drug release kinetics up to initial 10 hr. Stability evaluation indicated that both formulations were not significantly leaky over a period of one month. Niosomal formulation elevated plasma elimination half life and decreased elimination rate constants for rifampicin in vivo suggested that encapsulation retarded the removal of the drug from circulation compared to free drug due to slow drug release into systemic circulation. A five-fold increase in the area under plasma rifampicin concentration-time curve for niosomal rifampicin as compared to free drug indicated better bioavailability of encapsulated drug. It is evident from this study that niosomes and liposomes could be promising delivery systems for rifampicin with prolonged drug release profiles and reasonably good stability characteristics.

Evaluation of anti-tumor efficacy of injectable Centchroman in mice bearing Ehrlich ascites carcinoma.

Anti-tumor efficacy of Centchroman formulated as niosomes and gel implant was evaluated in Swiss albino mice bearing Ehrlich ascites carcinoma at 10 mg/kg body weight dose given subcutaneously. Median day of death, percentage increase in host life span and changes in body weight were studied. Centchroman significantly (P < 0.05) increased the median day of death both in free and formulated systems. Also, injectable formulations exhibited a significant (P < 0.05) increase in host life span compared to free drug, hence, enhanced anti-tumor efficacy against Ehrlich ascites carcinoma.

Antitumor and antifertility activities of plumbagin controlled release formulations.

With a view to increase efficiency and reduce toxicity of Plumbagin, an attempt was made to formulate plumbagin as a controlled release preparation using various carriers and test for their antitumor and antifertility activities. Niosomes and albumin microspheres were used as carriers. In vitro data showed promising results for these formulations thus they were taken up for in vivo assessment. Given at a dose of 5 mg/kg, ip the albumin microspheres showed promising antitumor and antifertility activity when compared to the niosomes on control. Animal survival data also indicated slight improvement in survival rate and thus antitumoral activity. Also, an interesting point was that the antifertility activity was affected through an antiovulatory action as seen from histopathological studies.