Cefdinir (CEF) is an antimicrobial drug with a wide spectrum of activity. It is mainly used in infections yet is not the first choice considering its solubility and bioavailability problems. The main aim of this study is to improve therapy with CEF by enhancing its solubility and improving dissolution properties. Solid dispersions have been preferred for this purpose and polyvinylpyrrolidone (PVP) has been used to develop two different formulations, PVP-1 and PVP-2. Physical mixture of PVP and CEF was also prepared for comparison. Formulations were prepared by lyophilization following probe sonication with different conditions. To ensure that our formulations have reached their purposes, further experiments were conducted. A specific and selective UV-visible spectrophotometric method was used to determine CEF concentration and the method was validated according to ICH guidelines for linearity, accuracy, and precision. Solubility studies were conducted with pure CEF, physical mixture (PM-PVP) and our solid dispersions, PVP-1, and PVP-2. Solubility studies confirmed CEF’s low solubility, less than 1 mg/mL, and showed a significant difference between pure CEF and solid dispersions. While there was also a significant difference between PM-PVP and both PVP-1 and PVP-2, there were no significant differences between PVP-1 and PVP-2. Therefore, PVP-2 was chosen as the optimum formulation and dissolution studies were conducted with PVP-2 and pure CEF in three different mediums, water, pH 1.2 and simulated intestinal fluid (SIF, pH 6.8), respectively. Solubility and dissolution profiles of pure CEF and the formulations were compared and evaluated according to literature. Our formulations were found to be successful in the purpose of improving therapy with CEF by demonstrating a better solubility with better dissolution profiles in all mediums.

Keywords: Cefdinir; solid dispersions; solubility enhancement; probe sonication