Experiment on formulation and drug release behavior of porosity asymmetric membrane capsules in vitro

Abstract

Porosity asymmetric membrane capsules were prepared to study the relationship between the capsule formulation and drug release. Cellulose acetate (CA) and pore formers were used in the capsule shell formulation as the main semipermeable membrane material. The capsules were permeable to both water and dissolved solutes. Using sparingly soluble drug acetaminophen as a model, cumulative release was calculated. The slope of the release profile from the distilled water had good relationship with the concentration of the pore formers F68. The release of acetaminophen was independent to the pH, osmotic pressure of dissolution medium, but influenced by intensity of agitation. When the concentration of pore former was low, zero-order release behavior was observed within 24 h which was consistent with Fickian diffusion model. When the concentration of pore former was high, however, Higuchi model release was found which is caused by Fickian diffusion and osmotic pressure release. With scanning electron microscope (SEM), the surface structure and cross-section of the capsule shell were also studied before and after drug delivery. With simple preparation and broad scope of drug application, porosity asymmetric membrane capsules can give desired drug extended release and show more convenience than controlled tablets with laser drilling.

Keywords::

• Asymmetric membrane capsule
• osmotic pump
• Fickian diffusion
• controlled release
• acetaminophen

Acknowledgments

The authors would like to acknowledge Professor Liu Long-xiao from College of Pharmaceutical Sciences, Zhejiang University.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this paper. The authors are grateful to the Government of China for providing for financial assistance. (Project of bureau of Science and Technology Innovation of Wenzhou municipality, S20100042; Project of bureau of Science and Technology Innovation of Pingyang county, AS201003; University Science and Technology Innovation Project of department of education of Zheiang province, 2010R413004.)