Self-Microemulsifying Drug Delivery System of Atorvastatin: Design and Pharmacokinetics

Atorvastatin is a highly effective statin whose oral bioavailability is limited by poor aqueous solubility and extensive pre-systemic metabolism. Self-microemulsifying drug delivery systems (SMEDDS), isotropic mixtures of oil, surfactant and cosurfactant that disperse spontaneously in gastrointestinal fluid, have been proposed to overcome these limits. This review draws on published formulation and pharmacokinetic studies and reports no new experimental data. It covers the biopharmaceutics of atorvastatin, excipient selection and design methods, in vitro characterisation, and animal pharmacokinetic findings. Reported systems consistently improve dissolution and exposure in animals, but human data, long-term stability and in vitro to in vivo correlation remain sparse and call for rigorous, standardised evaluation.