PENGARUH pH DAN KEKUATAN IONIK TERHADAP PROFIL KELARUTAN OFLOKSASIN

Abstract

Biopharmaceutics Classification System Solubility is one of drug physicochemical characteristics which determines the success of drug formulation process, especially in solution preparation. Ofloxacin is an antibiotic drug and categorized as class 2 drug in (BCS). The solubility of ofloxacin is dependent on pH of the solvent due to its amphoteric properties. The objectives of this research were to find and to determine the effects of pH and ionic strength on solubility profile of ofloxacin. Ofloxacin solubilities were measured at various pH and ionic strengths ranged from 1.5 to 12.5 and from 0.01 to 0.20 respectively. Solubility experiments were carried out using shaking thermostatic-waterbath for 3 hours at a temperature of 37°C � 1°C. The results showed that ofloxacin solubility increased at a pH values below the pKa1 (6.08) and above the pKa2 (8.25). However, the solubility decreased at pH value between pKa1 and pKa2. Changing the pH from 6.2 to 1.5 and 12.5, the ofloxacin solubility increased about 10 times. Ofloxacin solubility in various ionic strength showed that increasing of ionic strength cause the increasing of the solubility, that means there was salting in phenomena. Least- Square Fitting Analysis using Henderson-Hasselbalch equation for amphoteric compound were insufficient to describe ofloxacin solubility process in a series of pH