FORMULATION PARAMETERS OF ALBENDAZOLE SOLUTION

The solubility of albendazole, a poorly water-soluble drug was evaluat ed. The effect of cosolvents and pH on the aqueous solubility of alben dazole are described here. Albendazole aqueous solubility was tested o ver the pH range of 1.2-7.5. Albendazole solubility was lower for the highest pH values. The solubility coefficient obtained was 0.376 mg/ml in a 1.2 pH buffer solution. Transcutol was the cosolvent with which the increase of the solubility was highest. Albendazole solubility at different percentages oftranscutol presented a sigmoid kinetic with an initial acceleration phase. This kinetic shows an exponential correla tion for transcutol values smaller than 80%. The exponent value (n) wa s higher as the pH of the solution was increased. This high value of t he exponent (n) is due to a stronger influence of the transcutol on th e solubility of albendazole at elevated pH values. The albendazole sol ution containing 40% w/w of transcutol in a pH 1.2 buffer solution was selected because of its high solubility (2.226 mg/ml). Analysis of th e stability data of this albendazole solution showed good correlation (r = 0.9831) when the data were fitted to a first order equation. This albendazole solution showed good stability, with less than 10K degrad ation occurring after 30 days of storage at 4 degrees C.