The influence of excipients on physical and pharmaceutical properties of oral lyophilisates containing a pregabalin-acetaminophen combination

<p><b>Objectives:</b> The purpose of the study was to investigate and characterize the oral lyophilisates containing the pregabalin-acetaminophen drug combination and as xcipients mannitol with microcrystalline cellulose or hydroxypropyl methylcellulose, in order to conclude upon drug-excipient interactions and their stability implications, impact of excipients on drug release and on the physicochemical and mechanical properties of the pharmaceutical formulations.</p> <p><b>Methods:</b> The oral tablets were made by using a Christ freeze-dryer alpha 2–4-LSC lyophilizer, and evaluated for stability, drug-excipient compatibility and homogeneity of the prepared pharmaceutical formulations. The formulations were evaluated for <i>in vivo</i> absorption in rabbits by histopathological exams.</p> <p><b>Results:</b> FTIR and thermogravimetric analyses, DLS technique, SEM and NIR-CI studies confirmed the compatibility between compounds. From the determined physical and biochemical parameters of the formulations it was established that they are stable, homogeneous, and meet the conditions for orally disintegrating tablets.</p> <p><b>Conclusion:</b> In the case of the investigated pharmaceutical formulations the study evidenced the assembling through physical bonds between the excipients and the ‘codrug’ complex, which do not affect the release of the bioactive compounds.</p>