aqueous solubility

Solubility is an important physicochemical factor affecting absorption of drug and its therapeutic effectiveness. Drugs having poor aqueous solubility present one of the major confronts better absorption for good bioavailability of such drugs. The purpose of this study was to prepare and characterize solid dispersions of the poorly water soluble antihypertensive agent valsartan with water soluble carriers such as Kolliphor P 407, Kolliphor P 188, Kolliwax GMS II, Kolliphor HS15, HPMC AS and Soluplus in proportions viz. 1:1, 1:3, 1:5 (Drug: Carrier) with addition of 2% SLS to improve its aqueous solubility and rate of dissolution by solvent evaporation technique. All the formulations showed marked improvement in the solubility behavior and improved drug release. From all the formulations  SD6 was found to be optimized formulation  using soluplus as carrier based on the solubility and dissolution studies. The results obtained showed that the aqueous solubility and rate of dissolution was significantly improved when formulated in solid dispersion as compare to pure drug.

Clotrimazole (CLTZ) is a local imidazolic antifungal agent. A major problem associated with the successful formulation of effective dosage forms containing CLTZ is its poor aqueous solubility, which presents a hindrance for the local availability of CLTZ and limits the effective antifungal therapy. In the present study, the effects of various concentrations of poly(amidoamine) (PAMAM) dendrimers generation 3.5 (G3.5) and generation 4 (G4) with carboxylate (DCC), amine (DCN) and hydroxyl surface groups (DCO) on aqueous solubility, in vitro drug release studies, and for stability studies of CLTZ drug. The obtained results showed that all tested PAMAM dendrimers improved the solubility of CLTZ and the more potent were (DCC) dendrimers. The increase in solubility of CLTZ was highest at dendrimer concentration of 10 mg/ml. These observations indicate that PAMAM dendrimers enhance the solubility of CLTZ, The drug dendrimers complexes displayed the controlled release action during in vitro release studies. Formulation with amine and carboxylate were subjected to accelerated stability studies. Key words: poly(amidoamine) dendrimers; clotrimazole; aqueous solubility; surface groups