Co-Milling: A Successful Approach to Enhance Solubility of a Poorly Soluble Antihypertensive Drug

The aim of the work was to enhance the solubilization of Olmesartan-medoxomil (OM) and formulate stable, rapidly-dissolving-tablet formulations. OM, on the other hand, is classified as Biopharmaceutics Classification System (BCS) Class II drug, which indicates that it is characterized by water-insolubility. Therefore, increasing its solubilization has the potential to boost its bioavailability. For the OM evaluation, a new HPLC technique was invented and then validated in accordance with international standards. The formulation of tablets involved co-milling with certain superdisintegrants, specifically croscarmellose sodium (Ac-Di-Sol) and crospovidone in varying percentages, followed by mixing with pH-adjusting substances such as calcium carbonate to increase solubilization in cases where the drug is soluble in alkaline. Following the evaluation of the created formulations, the optimized formulations were selected for further stability assessment. Co-milling process with crospovidone greatly improved the olmesartan release. The optimized formulations were OD11 and OD12, which exhibited fast disintegration, and the release exceeded 90% within 10 min, while the release for Olmesartan medoxomil pure standard was 9.8% after 10 min. The OD11 and OD12 were chosen for further stability assessment and revealed good stability behavior, as the study on optimized formulations revealed that the degradation was less than 5% after storage for six months at 40 °C and 75% relative humidity. Some formulations exhibited good results in terms of disintegration and release. The results of the formulations (OD11 and OD12) suggested that co-grinding with crospovidone may increase the solubilization of OM to greater than 90% after 10 minutes.