Engineered Site Specific Vesicular Systems for Colonic Delivery: Trends and Implications

Abstract

Steering drug loaded, site-specific, coated lipid vesicles to the target receptor sites has the potential of plummeting adverse effects and improving the pharmacological response in diverse pathologies of large bowel, especially colon. Colonic delivery via oral route has its own challenges, often governed by several glitches such as drug degradation or absorption in the upper GIT, instability of proteins/peptides due to high molecular weight and peptidase activity in the stomach. Consequently, colon specific coated liposomal systems (CSLS) offer a potential alternate for not only site specificity, but protection from proteolytic activity, and prolonged residence time for greater systemic bioavailability. On the other hand, liposomal delivery via oral route is also cumbersome owing to several barriers such as instability in GIT, difficulty in crossing membranes and issues related to production at pilot scale. New advancements in the field of CSLS have successfully improved the stability and permeability of liposomes for oral delivery via modulating the compositions of lipid bilayers, adding polymers or ligands. Despite these ostensible propitiousnesses, no commercial oral CSLS has advanced from bench to bedside for targeted delivery to the colon as yet. Nevertheless, CSLS have quite fascinated the manufacturers owing to its potential industrial viability, simplistic and low-cost design. Hence, this review aims to decipher the convolutions involved in the engineering process of industrially viable CSLS for colonic delivery.