Surfactants solubility, concentration and the other formulations effects on the drug release rate from a controlled-release matrix

Abstract

Surfactant effects on the drug release from controlled release systems have been widely studied. These effects are dependent on the surfactant physical properties such as structure, charge, solubility and concentration. In addition, presence of excipients in the matrices can modify the surfactants effects. Here we investigated the effects of surfactant solubility and concentration of excipients on the drug release. Two cationic surfactants (cetrimide and cetylpyridinium chloride), two anionic surfactants (sodium lauryl sulfate and sodium taurcholate) and the amphoteric surfactant betaine were used. The used dissolution medium was simulated gastric fluid pH 1.2. The results revealed that surfactants of the same charge with the drug showed increase of drug release rate in concentration below the surfactant critical micelle concentration (CMC), while the increase in the drug release was to a less extent in surfactant concentration above its CMC. On the other hand, drug release rate was increased with surfactant solubility and vice versa. Surfactants of different charges with that of the drug resulted in a decrease in the drug release rate, depending on surfactant solubility and the excipients. The amphoteric surfactant increased the drug release rate depending on surfactant solubility and concentrations. Key words: Propranolol hydrochloride, surfactant solubility, controlled-release, surfactant concentration, drug release rate.