Characterization of the indinavir raw materials stability in some pharmaceutical processes

Abstract

This article characterizes the stability of indi- navir sulfate using different analytical techniques of quality control to evaluate important steps in the manufacturing process of indinavir, specifically involving storage and compression. Indinavir A, B, and C were obtained from different suppliers and submitted to DSC, Karl Fisher, NIR, XRPD analyses and dissolution assay. DSC curves of in- dinavir presented endothermic peaks of fusion at 149- 150 C for indinavir A and B (form I) and 139-143 C for indinavir C (form II). When indinavir A and B were sub- mitted to high Relative Humidity (RH) pseudo-polymor- phic form II was formed. Indinavir C converted into an amorphous substance when submitted to compression. Near infrared and Karl Fisher assays detected high values of water for indinavir C in relation to indinavir A and B. X-ray powder diffraction of indinavir B and C showed displacement of 0.05-0.10 h in the peaks and higher angle of diffraction in relation to indinavir A. Amorphous indi- navir C demonstrated a higher intrinsic dissolution rate than indinavir A and B. Indinavir form I should be moni- tored during the pharmaceutical process to avoid its con- version to indinavir form II or an amorphous substance which can alter the dissolution rate.