Availability of oxyphenbutazone from different suppository formulations

Area of Science:

• Pharmaceutical Sciences
• Drug Delivery Systems
• Pharmacokinetics

Background:

• Suppositories are a common rectal drug delivery system.
• Optimizing drug release and absorption from suppositories is crucial for therapeutic efficacy.
• Oxyphenbutazone is an anti-inflammatory drug with potential for rectal administration.

Purpose of the Study:

• To investigate the in vitro release and rectal absorption of oxyphenbutazone from various suppository formulations.
• To evaluate the impact of different bases and excipients on drug release kinetics.
• To establish a correlation between in vitro release and in vivo rectal absorption.

Main Methods:

• In vitro drug release studies using different suppository bases (polyethylene glycol, adeps solidus, Witepsol).
• Investigation of excipient effects (nonionic surfactants, hydrophilic aerosil) on drug release.
• Rectal absorption studies of oxyphenbutazone in rabbits.
• Correlation analysis between in vitro release data and in vivo absorption.

Main Results:

• Polyethylene glycol bases demonstrated superior oxyphenbutazone release compared to adeps solidus.
• Nonionic surfactants showed variable effects on drug release; hydrophilic aerosil reduced release.
• A specific mixture of Witepsol H 15/H 12 and Brij 58 (85:5) yielded the highest in vitro release.
• This optimal formulation also resulted in the highest rectal absorption of oxyphenbutazone in rabbits.
• A significant positive correlation was observed between in vitro release and rectal absorption.

Conclusions:

• Suppository base selection significantly influences oxyphenbutazone release and rectal absorption.
• Formulation optimization using specific excipient combinations can enhance drug delivery.
• In vitro release studies serve as a reliable predictor for in vivo rectal absorption of oxyphenbutazone.