Hydrotropic Approach for the Enhancement of Telmisartan Solubility

Telmisartan is a BCS Class II drug with low aqueous solubility and high permeability that exerts antihypertensive effects by selectively blocking angiotensin II type I receptors. However, its limited solubility in water restricts its oral bioavailability and therapeutic performance. Hydrotropy, a simple and economical solubilization technique, has gained attention as an effective approach to improve aqueous solubility of poorly soluble drugs. Unlike methods requiring organic solvents or complex formulations, hydrotropy utilizes safe, non-toxic, and non-flammable agents that enhance solubility through weak molecular interactions. In the present study, the hydrotropic technique was applied to telmisartan using sodium salicylate, sodium tartrate, urea, potassium acetate, and sodium benzoate as hydrotropic agents in different concentrations. These compounds are well-known for their ability to increase solubility by altering solvent properties and destabilizing the water structure. The results revealed an enhancement in the aqueous solubility and dissolution profile of telmisartan in the presence of the selected hydrotropes when compared with the drug alone. The percentage increase in solubility with urea was 1.08% (10%), 1.19% (20%), and 1.60% (30%); with sodium benzoate, it was 2.54% (10%), 3.41% (20%), and 4.07% (30%); with potassium acetate, 2.48% (10%), 3.07% (20%), and 3.796% (30%); with sodium salicylate, the enhancement was highest at 6.31% (10%), 6.68% (20%), and 7.07% (30%); and with sodium tartrate, it was 4.01% (10%), 5.61% (20%), and 6.56% (30%). Improved dissolution rates suggested the potential for increased bioavailability, since dissolution is the rate-limiting step for BCS Class II drugs. The study confirmed hydrotropy as a safe, practical, and efficient approach for enhancing telmisartan solubility and improving formulations of poorly water-soluble drugs.