Investigation on the supercritical carbon dioxide extraction of some polar drugs from spiked matrices and tablets

The orthogonal array design was applied to the optimization of supercritical fluid extraction (SFE) of three drugs, methimazole, phenazopyridine and propranolol from spiked glass matrices and tablets. Effects of four experimental factors: pressure, temperature, volume of modifier and dynamic extraction time on the SFE recovery of drugs was studied and optimized by a three-level OA9 (34) matrix. Under optimal experimental conditions >95% total recovery was obtained for all three drugs. Extractions from pharmaceutical dosages were less efficient than those from a glass bead matrix, under the same conditions. It was found that alkaline modifiers, such as methanol basified with diethylamine and potassium hydroxide could enhance the extraction yields of the hydrochloride salts of phenazopyridine and propranolol drugs from tablets.