Abstract

Solidified reverse micellar solutions (SRMS) are reverse micelles containing lecithin and a triglyceride, for example, SOFTISAN^®142, which is hydrogenated coco glyceride. SRMS transform into a lamellar mesophase after melting on contact with water; this transformation enables controlled release of solubilized drugs. They offer potentials for sustained drug delivery of both hydrophilic and lipophilic drugs. SRMS have the advantage of providing more flexibility in controlling the drug release and protecting the encapsulated ingredients from chemical degradation. SRMS based systems influence the absorption of active ingredients through different mechanisms to modify the release of active ingredients, and improve drugs bioavailability. The types of SRMS-based drug delivery systems include solid lipid nanoparticles (SLN), solid lipid microparticles (SLM), tablets and suppositories amongst others. The work exhaustively reviews the advances in SRMS based carriers. Its formulation methods, characterisation and delivery systems were discussed in details.

Key words: Solidified reverse micellar solutions (SRMS), lipids, wide angle X-ray diffraction analysis (WAXD), small angle X-ray diffraction analysis (SAXD), lipid absorption.

Abbreviation

Abbreviations: RMS, Reverse micellar solutions; LRMS, liquid reverse micelles; SRMS, solidified reverse micellar solutions; LDDS, lipid based drug delivery system; P-gp, P-glycoprotein; WAXD, wide angle X-ray diffraction analysis; SAXD, small angle X-ray diffraction analysis; TEM, transmission electron microscopy; PCS, photon correlation spectroscopy; SLN, solid lipid nanoparticles; m.p., melting points; SLM, solid lipid microparticles; NSAIDs, non-steroidal anti-inflammatory drugs; CMC, critical reverse micelle concentration.