Oral delivery of bovine lactoferrin by using pectin- and chitosan-modified liposomes and solid lipid particles: improvement of stability of lactoferrin

Abstract

A critical problem associated with delivery of bovine lactoferrin (bLf) by the oral route is low bioavailability, which is derived from the enzymatic degradation in the gastrointestinal tract and poor permeation across the intestinal epitheliums. Particulate carrier systems have been identified to protect bLf against proteolysis via encapsulation. This study aimed to evaluate the physico-chemical stability of bLf loaded liposomes and solid lipid particles (SLPs) modified by pectin and chitosan when exposed to various stress conditions. TEM results showed liposomes and SLPs had a classic shell-core structure with polymer layers surrounded on surface but the structure appeared to be partially broken after digestion in simulated intestinal fluids (SIF). Although HPLC and SDS-PAGE methods qualitatively and quantitatively described either liposomes or SLPs could retain intact bLf against proteolysis in SIF to some extent, all liposome formulations showed rapid rate of lipolysis mediated by pancreatic enzymes. On the other hand, all SLP formulations showed higher heat resistance and greater electrolyte tolerance compared to liposome formulations. After 180 days storage time, liposome loaded bLf was completely degraded, whereas almost 30% of intact bLf still remained in SLP formulations. Overall, solid lipid particles (SLPs) are considered as primary choice for oral bLf delivery.