Efficient drug development of oseltamivir capsules based on process control, bioequivalence and PBPK modeling

Oseltamivir phosphate is used to treat influenza. For registration of a generic product, bioequivalence studies are crucial, however, in vitro studies can sometimes replace the conventional human pharmacokinetic. To assess whether the dissolution profile is comparable with the in vivo release, physiologically based pharmacokinetic absorption models (PBPK) are being used. The aim of the study was to develop a generic capsule of oseltamivir phosphate 30 mg with process understanding and control, development of PBPK model and comparison of virtual bioequivalence study (VBE) to the real bioequivalence study that was also performed. For that, 30 mg capsules were prepared by wet granulation according to 2² full factorial design. The biobatch was prepared with the selected process and a batch was made with the API from the second manufacture. Both manufactures presented polymorph A and the second manufacture showed higher particle size. Product batches produced without adding water during granulation showed higher dissolution. The addition of water associated with higher conical mill speed, lowered the average weight of the capsules. The biobatch dissolution was similar to Tamiflu; also, they were bioequivalent. The crossover VBE between the biobatch and Tamiflu corroborated with the real bioequivalence study. The same result was found for the batch with higher particle size. PBPK model showed that computer simulations can help pharmaceutical companies to replace in vivo studies.