Linear drug release from laminated hydroxypropyl cellulose-polyvinyl acetate films

Area of Science:

• Pharmaceutical Sciences
• Materials Science
• Drug Delivery Systems

Background:

• Drug release from single-layer films typically follows a diffusion-controlled matrix model, proportional to the square root of time.
• Achieving zero-order (linear) drug release kinetics is desirable for consistent therapeutic effects.
• Lamination of films offers a potential strategy to modify drug release profiles.

Purpose of the Study:

• To investigate the potential of a laminated film system for achieving zero-order drug release.
• To evaluate the influence of membrane properties on drug release rates.
• To compare the release kinetics of different model drugs within this system.

Main Methods:

• Fabrication of laminated films with a drug-containing reservoir layer (hydroxypropyl cellulose with pentobarbital, methapyrilene, or salicylic acid) and a non-drug membrane layer (hydroxypropyl cellulose/polyvinyl acetate mixtures).
• Analysis of drug release kinetics over time.
• Systematic variation of membrane thickness and composition.

Main Results:

• Zero-order drug release kinetics were successfully achieved in the laminated film system.
• Drug release rate showed an inverse relationship with membrane thickness.
• An inverse relationship was observed between the logarithm of the release rate and the percentage of polyvinyl acetate in the membrane.
• Salicylic acid exhibited the fastest release, while pentobarbital showed the slowest.

Conclusions:

• Laminated films can effectively control drug release kinetics, transitioning from square root of time to zero-order profiles.
• The membrane layer's thickness and composition (specifically polyvinyl acetate content) are critical factors in modulating drug release rates.
• This approach offers a viable strategy for developing controlled-release pharmaceutical formulations.