he Cmax for marketed formulation and formulation S1 was found to be 1.9±0.011 and 5.9±0.081 s, respectively. The Tmax for both marketed and formulation S1 was found to be 90 min. The AUC for the marketed formulation and formulation S1 was found to be 114 and 322.8, respectively. Hence, the relative bioavailability in rabbits for formulation S1 (stavudine+crospovidone+sodium starch glycollate) was found to be 2.83 times greater than that of conventional tablets (fig. 3). This confirms that the hepatic metabolism was reduced when the drug is given in the form of oral disintegration tablets.
Fig. 3
Fig. 3
The ODT stavudine formulations were prepared by direct compression technique using crospovidone and sodium starch glycollate as superdisintegrants in different ratios. The wetting time and disintegration time was found to be less in the formulation S1. Profound in vitro release in 120 min (99.3±0.46%) was found in S1 formulation (stavudine+crospovidone+sodium starch glycollate) due to the inclusion of combination of superdisintegrants in the concentration of 20%. The result outcome confirms inclusion of starch at 7% concentration increases the disintegration time as seen in formulation S9 because of the binding nature of starch with the drug. Formulation S14 which has Eudragit RL 100 at 20% concentration did not show encouraging in vitro results inspite of the presence of both the superdisintegrants, sodium starch glycollate and crosspovidone. Hence, addition of Eudragit RL 100 is not advisable for the formulation of oral disintegration tablets. The relative bioavailability for the optimized formulation S1 was found to be 2.83 times greater than the marketed capsule formulation, which confirms the decreased hepatic metabolism the of the drug. However, the formulation S2 (stavudine+crospovidone+sodium starch glycollate) which has 10% of superdisintegrants did not give encouraging bioavailability results. Saccharin sodium included in the formulation will help to overcome the bitter taste of stavudine; however, the prepared tablets should be evaluated for taste by panel testing in healthy human volunteers. From this study, we perceive the possibility of commercializing ODT formulation of stavudine as it has much better release profile and enhanced bioavailabilty when compared to the marketed capsule formulations. Moreover, this approach may increase drug bioavailability and patients compliance which is an important prerequisite for HIV management.