Lipid-based formulations (LBFs) are an alluring alternative among novel
drug delivery formulations that are used for the improvement in solubility and
bioavailability of drugs that are impossible to dissolve because of their limited
solubility in the gastrointestinal tract. As a controlled and targeted formulation,
LBDDS includes the discharge of drugs in a controlled manner, high drug loading
capacity (as compared to others), biodegradable and biocompatible, carrying
capabilities for both lipophilic and hydrophilic drugs and excipients with less risk
profile. The most imperative classification in novel drug delivery systems is LBFs
including self-emulsifying lipid formulations, lipid solutions and lipid suspensions.
Emulsions, microemulsion, nanoemulsion, liposomes, solid lipid nanoparticles,
niosomes, lipospheres, ethosomes, self-emulsifying drug delivery system and selfmicroemulsifying
drug delivery systems. GI lipid digestion is a mechanism of lipidbased
drug delivery systems that is based on the dispersion of oil droplets to give a fine
formulation of emulsion, hydrolysis of fatty acid esters with the help of enzymes at the
emulsion water interface, desorption and dispersion of insoluble lipid products for
absorption. Various mechanisms for upgrading the drug retention include improvement
in dissolution/solubilization rate, the extension of gastric retention time; changes in the
physical barrier role of the gastrointestinal tract, change in biochemical hindrance
capacity of the GI tract, drug assimilation through the intestinal lymphatic system, all
of these are discussed in detail. Lipid digestion, hydrophobic nature of the API and
mean emulsion droplet sizes are various formulations factors that influence the
bioavailability of drugs from LBDDS. Porter outlined seven regulations for the
development of LBFs. This chapter highlights various types of lipid-based drug
delivery systems with their benefits and drawbacks.
Keywords: Formulation factors, Lipid-based drug delivery systems, Lipid
digestion, Mechanisms improving drug retention, Self micro-emulsifying drug
delivery system, Solid lipid nanoparticles.
