ABSTRACT:
Sustained release microspheres of Stavudine, the FDA- approved drug for the treatment of HIV infections, AIDS and AIDS- related conditions administered either alone or in combination with other antiretro-viral agents. Stavudine is typically administered orally as a capsule and an oral solution. The virustatic drug has a very short half-life (1.30h). Its dose is 40mg twice or thrice daily. However patients receiving stavudine develop neuropathy and lactic acidosis. The side effects of stavudine are dose dependent and a reduction of the total administered dose reduces the severity of the toxicity. Microencapsulation is a process whereby one can formulate controlled/sustained action dose form for drugs having a short half-life. Microencapsulation improves the drug absorption and minimizes side effects due to the localized build up of drugs against the gastrointestinal mucosa. The main objective of the present study was to formulate sustained release microspheres of stavudine which will retard drug release from dosage form, reduces the frequency of drug administration, minimizing the adverse effects thereby increasing the patient compliance. Sustained release microspheres were prepared by single emulsion technique followed by heat denaturation and chemical cross linking with gluteraldehyde using egg albumin as a release retarding agent. These microspheres were evaluated for yield, flow properties, entrapment efficiency and in-vitro release kinetics. The results showed that yield, entrapment efficiency was influenced by polymer concentration and stirring speed. Results of the in vitro study showed that the desired release rate was achieved by F6, F5 formulations releasing drug up to 12hrs. FT-IR results proved that there is no interaction between drug and polymer. SEM results of optimized microspheres showed discrete, spherical microspheres.