US EPA

1620204 

Journal Article 

Sustained release from reverse micellar solutions by phase transformations into lamellar liquid crystals 

Mueller-Goymann, CC; Hamann, HJ 

1993 

Yes 

Journal of Controlled Release
ISSN: 0168-3659
EISSN: 1873-4995 

IPA/93/1027124 

Controlled Release 

REF 15 

165-174 

eng 

IPA COPYRIGHT: ASHP The phase transformation of reverse micellar solutions of fenoprofen or fenoprofen sodium in isopropyl myristate formed in the presence of phospholipids into a liquid crystal induced by addition of water was investigated and the effect of the phase transformation on fenoprofen and fenoprofen sodium release was studied by small angle X-ray scattering and viscosimetry. The increase of water content caused a change in shape and size and finally a phase transformation from the reverse micellar solution into a lamellar liquid crystal. Solubilization of the drug in its free acid form resulted in almost spherical micelles, while solubilization of drug in its sodium salt form resulted in cylindrical micelles. The lamellar liquid crystals that form on contact with aqueous media can be used for sustained release, as the diffusion coefficient of the drug within the liquid crystals is smaller by factor 100 than that within an oily solution. The apparent diffusion coefficient of the drug depends on the thickness of the liquid crystalline interface, which is also influenced when either the free acid or the salt is solubilized in the system. 

Fenoprofen; release; sustained; Fenoprofen sodium; Isopropyl myristate; vehicles; fenoprofen; Water; effects; Anti-inflammatory agents; sustained release; fenoprofen(Anti-inflammatory agents; fenoprofen sodium(Anti-inflammatory agents; Crystals; sustained release; Micelles; sustained-action; Sustained-action medications; release