In vitro Lipolysis: An Indispensable Tool for the Development of IVIVC of Lipid Based Drug Delivery Systems

Background and Objective: Around 70% of the pipeline drugs and 40% of marketed drugs come under the BCS class of II and IV. Dissolution of these drugs is a major concern for formulation scientists as poorly soluble drugs consequently affects the bioavailavbility, thus reducing the therapeautic efficacy of these drugs. Discussion: This has led to the development of various new technologies like solid dispersions, micro and nanoparticles of various natural, semi-synthetic and synthetic polymers, among others, of which, the more efficacious lipid based delivery systems have gained wider attention, chiefly due to their lipophilicity and at the same time be safe and economic for commercialisation. But a major hurdle in this regard is the unavailability of proper guidelines regarding characterisation of the lipid based formulations. Majority of the cases, the in vitro characterisation data could not be correlated with that of in-vivo data owing to several physiological factors like lipase, co-lipase, bile salts, pH, etc. Normal dissolution methods are unable to assess the different transformation in the lipid systems in presence of in-vivo conditions affect the drug release rate and thereby the bioavailability. Conclusion: This review covers in vitro lipolysis studies, their working principles, various developments and associated analytical techniques. This review will also focus on how in vitro lipolysis studies play a major role in characterising as developing an in vitro in-vivo correlation (IVIVC) for lipid based formulations.