Formulation and evaluation of controlled release matrices of ketoprofen and influence of different co-excipients on the release mechanism

The present work reports the study of different controlled release formulations of ketoprofen, which is a non-steroidal anti-inflammatory drug (NSAID) and like other NSAIDs requires large and frequent daily doses, resulting in severe side effects and non-compliance. To avoid these problems, controlled release matrices were developed using different grades of ethylcellulose polymer with a drug-polymer ratio of 10:3 by the direct compression method. The effect on drug release of partial replacement of lactose by different co-excipients, HPMC K100 M, starch and CMC, was also studied. The tablets were tested for their drug content, weight variation, friability, hardness, thickness and diameter, all these physical properties being within the USP range. The release profile of all formulations containing polymer and co-excipients was compared with a formulation developed without polymer and co-excipients. After a 24-hour release study, it was concluded that formulations containing different grades of ethylcellulose polymer showed prolonged release for 6-18 hours, but the formulation containing the polymer Ethocel standard FP 7 Premium without co-excipient showed controlled release for 24 hours. DSC and FT-IR studies were performed to investigate any incompatibility between drug, polymer and co-excipient but no interaction was found. Different kinetic models were used, such as first order equation, zero order equation, Higuachi equation, Hixon Crowel's equation and Korsmeyer-Peppas to study the release mechanism. The formulations containing co-excipients showed an enhanced release rate.