Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 9/10/2008
Publication Date: 9/10/2008
Citation: Muhidinov, Z., Bobokalonov, J., Liu, L.S., Fassihi, R., 2008. A kinetic study of a poorly water soluble drug released from pectin microcapsules using diffusion/dissolution model. Chapter 11, in New Delivery Systems for the Controlled Drug Release from Naturally Occurring Materials by N. Parris, L. S. Liu, C. Song and V. P. Shastri (Eds.):American Chemical Symposium Series 992, p.193-208.
Technical Abstract: A new microcapsular system for controlled drug delivery was developed from pectins obtained from various sources, with different molecular weight and degree of esterification. The release kinetics of a poorly water-soluble drug from the pectin microcapsules was investigated in simulated gastrointestinal fluids using prednisolone as a model drug. The work evaluated the effects of pectin macromolecular characteristics and the nature of surfactant and manufacturing conditions on the release kinetics of encapsulated drugs. The correlation between emulsion systems and drug release profiles was studied through the diffusion/dissolution number, which represents the combination of dissolution and diffusion kinetic parameters in one parameter. The microparticular diffusion coefficients determined by two different kinetic models are much smaller than analogues for other microparticular systems, indicating the critical step of intraparticular diffusion in drugs released from pectin microcapsules. The highest value of drug dissolution/diffusion number was obtained for microcapsules from high methoxylated apple pectin in the presence of anionic surfactants and calcium ions, rather than for the systems of highly charged citrus pectin. Capsules prepared by the use of ethyl acetate also showed retarded drug release, however the amount of drug encapsulated was much less than those from other emulsion systems. All the microcapsules had drug release half-life time (t50%) of more than 5 hours. The rapid release of prednisolone was achieved in the presence of pectinase. These results suggested the application of biodegradable pectin polysaccharides in the production of vastly diverse drug carrier systems for colon-specific drug delivery.