title: Manufacturing factors affecting the drug delivery function of thermo-responsive membrane prepared by adsorption of binary liquid crystals.
abstract: A binary mixture of cholesteric oleyl carbonate (COC) and cholesteryl nonanoate (CN) with a weight ratio of 36% and 64% was adsorbed onto the cellulose nitrate membrane to prepare a thermo-responsive membrane. The thermo-responsive function of these COC/CN-adsorbed membranes was evaluated by an in vitro penetration study via repeatedly exchanging the temperature cycle. The manufacturing factors for preparing these thermo-responsive membranes, such as the binary COC/CN concentration used, immersion temperature of binary COC/CN chloroform solution, immersion temperature and time period of distilled water, vacuum-drying or air-drying process, and vacuum drying temperature, have been explored. The results indicated that the immersion temperature at 23 degrees C for membrane in binary COC/CN chloroform solution with 10 min and in distilled water with 12 h was the optimal temperature for fabricating the on-off thermo-responsive membranes prepared either by 22% or 25% concentration of binary COC/CN mixture. A good thermo-responsive function was further evidenced for these COC/CN-adsorbed membranes via vacuum-drying at 65 degrees C for 1 h. A possible mechanism concerning the thermal-dependent molecular motion, orientation and/or alignment of binary COC/CN mixture entrapped into the membrane may play an important role for the thermo-responsive behavior.
authors.affiliation: Biopharmaceutics Laboratory, Department of Medical Research and Education, Veterans General Hospital--Taipei, Taipei, Taiwan. sylin@vghtpe.gov.tw
authors.forename: Shan-Yang
authors.initials: SY
authors.lastname: Lin
authors.forename: Hsiu-Li
authors.initials: HL
authors.lastname: Lin
authors.forename: Mei-Jane
authors.initials: MJ
authors.lastname: Li
mesh_terms: D000327:Adsorption / Q000187:drug effects; D003460:Crystallization; D016503:Drug Delivery Systems / Q000379:methods*; D006358:Hot Temperature; D008567:Membranes, Artificial; D010539:Permeability / Q000187:drug effects; D013678:Technology, Pharmaceutical / Q000379:methods*; D013696:Temperature
chemical_list: D008567:Membranes, Artificial