Dissolution testing for prolonged-release solid dosage form containing drug substances degrading in test media. Application to polymeric delivery systems of paracetamol

Synthetic biodegradable polymers are widely used as materials for the targeted drug delivery and controlled release devices. In order to control the rate of drug release from polymer scaffolds surface ordinary dissolution testing is performed. It includes placing a device into testing media, taking probes at determined time and estimating the drug concentration. As for prolonged release the issue is the drug degradation in test media what leads to false interpretation of results. This study was focused on the investigation of paracetamol degradation in phosphate buffer saline media for three days and its effect on the results of polymeric drug delivery system dissolution test. It was shown, that relative error in the released drug concentration evaluation can rise up to 34% depending on the exposure time and the initial probe concentration. An approach of experimental results correction is proposed.