Formulation and Evaluation of Liquisolid Compacts for Olmesartan Medoxomil

Olmesartan medoxomil is an angiotensin type II receptor blocker, antihypertensive agent, administered orally. It is highly lipophilic (log P 5.5) and a poorly water-soluble drug with absolute bioavailability of 26%. The poor dissolution rate of water-insoluble drugs is still a major problem confronting the pharmaceutical industry. The objective of the present investigation was to develop liquisolid compacts for olmesartan medoxomil to improve the dissolution rate. Liquisolid compacts were prepared using Acrysol El 135 as a solvent, Avicel PH 102, Fujicalin and Neusilin as carrier materials, and Aerosil as coating material in different ratios. The interaction between drug and excipients was characterized by DSC and FT-IR studies, which showed that there is no interaction between drug and excipients. The powder characteristics were evaluated by different flow parameters to comply with pharmacopoeial limits. The dissolution studies for liquisolid compacts and conventional formulations were carried out, and it was found that liquisolid compacts with 80%？w/w of Acrysol EL 135 to the drug showed significant higher drug release rates than conventional tablets. Amongst carriers used Fujicalin and Neusilin were found to be more effective carrier materials for liquid adsorption. 1. Introduction As a most discussed but still not completely resolved issue, solubility or dissolution enhancement techniques remain the most vibrant field for the researchers in formulation science. Solubility and dissolution are the core concepts of any physical or chemical science including biopharmaceutical and pharmacokinetic considerations in therapy of any medicine. The solubility/dissolution behavior of a drug is key determinant to its oral bioavailability, the latest frequency being the rate-limiting step of absorption of drugs from the gastrointestinal tract. As a result, more than 40% of new candidates entering drug development pipeline fail because of nonoptimal biopharmaceutical properties [1]. Over the years, various techniques have been employed to enhance the dissolution profile and, in turn, the absorption efficiency and bioavailability of water insoluble drugs and/or liquid lipophilic medication [2]. Several researchers have shown that the liquisolid technique is the most promising method for promoting dissolution rate of poorly water-soluble drugs [3–5]. The liquisolid technology is described by Spireas as liquid may be transformed into a free-flowing, readily compressible, and apparently dry powder by simple physical blending with selected excipients named the carrier