The capping tendency of the tablets selleck was examined during compression and hardness
testing which was found absent. The drug content in the prepared tablets was found in the range of 99.5 ± 0.37% to 100.85 ± 0.52%. The formulation and physical characteristics of the prepared matrix tablets are summarized in Table 1. The formulations of LAMI before and after compression were exposed to different humidity conditions. The moisture uptake was negligible in both the powder blends and tablets at 33% RH and it was higher at 90% RH. Further, it was proportional to the percent relative humidity (RH). The moisture uptake of powder blends was found more than that of tablets due to larger surface area of the former (Fig. 1). However equilibrium moisture was attained after 96 h in all the samples. Therefore the prepared matrix tablets and powder blends could be stored at room temperature and below 50% RH. The matrix tablets prepared with a combination of HPMC and PEO, showed the slower release when compared to those prepared with HPMC alone. The formulation F-1 released 74 ± 1.6% of the drug in 12 h. It was clearly observed that LAMI release from the formulations was inversely proportional
to the concentration of HPMC. The initial release of LAMI from the formulations prepared using the combination of HPMC and PEO varied Lenvatinib in vitro between 5.0 ± 0.6% to 11.0 ± 0.8% in the first hour, whereas it was 7.0 ± 0.4% to17 ± 0.7% for those prepared employing HPMC alone. This variation in the release at initial hour could be due to the polymer proportion and type of polymer employed in the Calpain preparation of the matrix tablets. But the drug release was
more controlled in the later stage of dissolution from the tablets prepared using higher polymer concentrations (Fig. 2) and it was extended up to 14 h. The higher correlation coefficients (r2) of 0.984–0.997 were observed from zero order plots as against those of first order plots with r2 of 0.905–0.967 indicated that the drug release was independent of the concentration and followed zero order release kinetics. The zero order release rate constants obtained in the formulations (F-1 to F-3), prepared using HPMC and PEO were between 6.1 and 7.2 h−1. The release kinetics was best fitted to the Higuchi model due to higher values of r2 which showed that the drug release mechanism was predominantly diffusion controlled. Similar patterns of drug release kinetics were observed in the matrix tablets prepared with HPMC alone (F-4 to F-6). The time to release 50% (T50) of LAMI was found 6.96–8.16 h in matrix tablets prepared using a combination of HPMC and PEO and it was 5.39–7.96 h for those prepared employing HPMC alone which clearly indicated that the drug release was for prolonged periods up to 14 h. The summary of drug release kinetics data of XR LAMI matrix tablets are shown in Table 2.