Lipolysis and structure controlled drug release from reversed hexagonal mesophase

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• 作者：Nissim Garti ; ^{garti@vms.huji.ac.il} ; Geut Hoshen ; Abraham Aserin
• 关键词：Lyotropic liquid crystals ; Sustained release ; Sodium diclofenac ; TLL lipase ; Enzymatic reaction ; Interfacial reactivity
• 刊名：Colloids and Surfaces B: Biointerfaces
• 出版年：2012
• 出版时间：1 June, 2012
• 年：2012
• 卷：94
• 期：Complete
• 页码：36-43
• 全文大小：1086 K

文摘

The present work investigates a system composed of a ternary reversed hexagonal mesophase (H_II) loaded with a lipase for modulating drug delivery capabilities of the system. Thermomyces lanuginosa lipase was solubilized into H_II mesophase for the benefits of continuing lipolysis of the lipids, consequently disordering and decomposing the hexagonal mesophase and thereby enhancing the diffusion of the encapsulated drug.

A single transition from the H_II structure to a random micellar phase was detected during the lipolysis. In the first lipolysis stage the hexagonal system (glycerol monooleate, tricaprylin, and water) preserved its symmetry within ca. 200 min. During this step about 40-60 % molar of the lipids were hydrolyzed, and a gradual shrinking of the H_II cylinders (decrease of 8 ? in lattice parameter) was detected. In the second lipolysis stage, the H_II mesophase gradually disintegrated (faster rate) and the release of a model drug (sodium diclofenac) was significantly enhanced, which was assumed to be lipolysis rate-controlled. After about 15 h the H_II mesophase was disintegrated into two dispersed immiscible phases.

The release obeyed two-step Higuchi kinetics with two consecutive linear correlations of the drug release.