Effect of Explotab on the tabletability of a poorly soluble drug

The efficiency of a superdisintegrant (Explotab) in a direct-compression formulation containing a poorly water soluble drug (albumin tanate) at high dosage was investigated. An experimental design with two variables, applied pressure and concentration of Explotab, enabled its effects on the tableting and the mechanical properties of the final tablets to be determined. Differential scanning calorimetry was performed to study the interactions between drug and excipients. No incompatibility was found between drug-excipient mixtures prepared in the proportion 1:1 and in the corresponding formulation at room temperature and after 3 weeks at 50 degrees C. The concentration of Explotab has a positive effect on flow properties. Also, the effect of applied pressure and disintegrant content was found to be significant on all compressional parameters. At low applied pressures, the breaking strength was independent on Explotab concentration. However, at higher applied pressures, the maximum densification obtained with 10% Explotab produced a limited breaking strength lower than that at 0% concentration. The response surface shows a certain level of Explotab, around 7%, at which the disintegration time was the shortest. At this level, the surface response was independent of the applied pressure. In our study, the experimental design was a valuable tool used to establish the optimum manufacturing conditions.