Current HIV-therapy recommends combination of stavudine, lamivudine and nevirapine.
Stavudine and lamivudine are administered as fixed combination while nevirapine as separate dosage
form which often results in poor compliance and adherence to therapy by patients and therefore, there
is a need to develop dosage forms that can overcome the problems of currently available dosage forms
for treatment of HIV infection. The present study developed a single unit osmotic system for simultaneous
and extended delivery of stavudine, lamivudine and nevirapine that can ensure patients compliance
and adherence to HIV-therapy. Sandwich osmotic pump tablets (SOPTs) of stavudine, lamivudine
and nevirapine in fixed dose combination were designed and evaluated for the effect of variables such as PEO
(polymer), KCl (osmogen), and orifice diameter on the physicochemical characteristics and the release behavior of the
drugs. A 24 h zero order release of stavudine, lamivudine and nevirapine from the formulations was observed and the release
rate of the drugs was found to be affected by PEO, KCl, and orifice diameter. The in vitro release data of SOPT correlated
with in vivo predictions by super - position method. The results of the study propose that a single unit osmotic system
(SOPT) of stavudine, lamivudine and nevirapine is beneficial to overcome the disadvantages of currently available
dosage forms for effective control of HIV infection.