Captopril floating and/or bioadhesive tablets: design and release kinetics

Area of Science:

• Pharmaceutical Technology
• Drug Delivery Systems

Background:

• Captopril is a widely used antihypertensive drug.
• Conventional dosage forms may require frequent administration.
• Developing controlled-release formulations can improve patient compliance and therapeutic efficacy.

Purpose of the Study:

• To formulate and characterize captopril floating tablets for sustained drug release.
• To investigate the influence of formulation parameters on drug release and tablet buoyancy.

Main Methods:

• Floating tablets were prepared using hydroxypropylmethylcellulose (HPMC) of two viscosity grades (4000 and 15,000 cps) and Carbopol 934P.
• In vitro dissolution studies were conducted in simulated gastric fluid at 37°C using USP apparatus 2.
• Drug release kinetics were analyzed using Higuchi, Korsmeyer-Peppas, and first-order models.

Main Results:

• Floating tablets demonstrated prolonged release of captopril compared to conventional tablets, achieving 24-hour controlled release.
• Drug release kinetics best fitted the Higuchi and Korsmeyer-Peppas equations, indicating diffusion-controlled release.
• Tablet hardness was a significant factor for tablet buoyancy, while stirring rate had minimal impact on release.

Conclusions:

• Hydroxypropylmethylcellulose and Carbopol 934P are suitable excipients for developing captopril floating tablets.
• The developed floating tablets offer a promising 24-hour controlled-release dosage form for captopril.
• Tablet hardness is a critical parameter to optimize for effective buoyancy and sustained drug delivery.