Lipid Microparticles for Oral Bioavailability Enhancement

A variety of potent lipophilic drugs exhibits low oral bioavailability due to poor water solubility of drugs. These drugs are challenging for the formulation scientists with regard to solubility and bioavailability (BA). Extensive efforts are ongoing to enhance oral BA of these types of drugs to increase clinical efficacies. The most common approach is the use of highly developed lipid-based drug delivery systems. This is a strategy to incorporate drug into the safe and biodegradable lipids (natural, semi-synthetic, vegetable oils or hydrolyzed solid lipids) with improved oral bioavailability. Lipid microparticles (LM) are efficient lipid based drug delivery system which might be prudent attempt to increase the oral bioavailability of poor aqueous soluble drugs. Lipid based systems are recognized as a potential approach for the improved oral absorption which ultimately caused to enhanced BA. Wide variety and range of substances have been reported to be entrapped into lipid microparticles including lipophilic and hydrophilic molecules as well as labile proteins and peptides. Moreover, LM can protect drugs from in vitro and in vivo degradation. Several authors reported numerous techniques and methods to enhance drug solubility by exploiting lipids while formulation development. The use of LM is a novel carrier to enhance oral BA of poor aqueous soluble drug. Lipids are well known to deliver a number of drugs with profound systemic availability either through portal vein or lymphatic absorption from gastro-intestinal tract. These lipids are belonging to triglycerides (short chain, medium chain and long chain) with or without double bond in their hydrocarbon chain length. The present chapter discusses the physico-chemical properties, processing techniques necessary to obtain lipid-based microparticles formulations for oral delivery along with a brief discussion of lipid excipients and their characterization. The chapter provided related patents with valuable informations for pharmaceutical research groups which would be very informative and instructive.