Development and Characterisation of Valsartan Immediate Release Dosage Form Using Solubility Enhancement Technique

Abstract Objective The objective of the present investigation is to improve the solubility of valsartan and prepare immediate release tablets. Materials and methods To increase the solubility and bioavailability of valsartan, a low-soluble antihypertensive drug, immediate release dosage forms were formulated by a direct compression method using a solid dispersion technique with three different carriers (β-cyclodextrin, polyvinyl pyrrolidone K30 and poloxamer 188) at three different ratios (1:3, 1:4 and 1:5). Nine physical mixtures (PM1–PM9) were prepared and various physical parameters were characterised in in vitro release studies. Results Out of the prepared physical mixtures, PM8 showed the best results, with 94.2% of the drug dissolving within 30 min. Formulation PM8 solid dispersion further used for the preparation of valsartan immediate release tablets by using sodium starch glycolate superdisintegrant, at different concentrations (3%, 4% and 5%; i.e., IF1, IF2 and IF3 formulations, respectively). The optimised formulation showed friability and disintegration values of 0.456±0.9 and 6.2±0.4 min. Among the three immediate release formulations, IF2, which contains 4% sodium starch glycolate, demonstrated an 84.46% drug release in 30 min and a 99.69% drug release in 1 hr, indicating increased drug solubility. When compared with a valsartan pure drug, the solubility of the solid dispersion increased by 135.06-fold. Discussion and conclusion The results show that the optimised IF2 formulation demonstrated enhanced drug solubility by 135.06-fold, using a solid dispersion technique with poloxamer 188. This can be explained by the conversion of crystalline to an amorphous form of drug, leading to a reduction in the contact angle between the drug and the gastric medium. It can be concluded that poloxamer 188 is a suitable carrier and that use of a physical mixture technique is an applicable method to improve the solubility of valsartan.