Oral Administration of Liposomal Insulin

Abstract

There have been several attempts published in the literature related with orally effective insulin formulations, which are increasing in popularity. Some of the results indicate that it is possible to reduce blood glucose level by orally administered liposomal insulin formulations, but there is general need to understand the mechanism and effective components of the liposome formulations. In our study, liposomal insulin formulations were prepared using insulin (Humulin R) or protamine- containing insulin (Humulin N) with cholesterol, dipalmitoyl phosphatidylcholine (egg) (DPPC)-cholesterol mixture, and mucoadhesive agent (methyl cellulose, MC)-added DPPC-cholesterol mixture. A tablet formulation of insulin was also prepared. Formulations of liposomal insulin were introduced to mice and rats orally and reduced blood glucose levels were observed. The composition of phospholipid (DPPC, cholesterol and MC mixture) was found to be quite effective in reducing blood glucose levels. The pH of the solution and the presence of the protamine sulfate were found to be important. The application site was also found to be important because liposomal insulin formulations administered through the mouth or esophagus resulted in reduced blood glucose levels. Reduced blood glucose levels were also observed when tablet formulations of insulin were administered to rats orally.

Phospholipids and Lipid-Based Formulations in Oral Drug Delivery

“…Several attempts have been made to improve the potency of insulin-loaded liposomal systems, e.g., insulin and protamine-containing insulin, respectively, were formulated with a cholesterol, dipalmitoyl phosphatidylcholinecholesterol (DPPC) mixture, and mucoadhesive agent (methyl cellulose (MC))-added DPPC-cholesterol mixture (15). The liposomal insulin was given to mice and rats by gavage; subsequently, reduced blood glucose levels were observed.…”

The Effectiveness of Raloxifene-Loaded Liposomes and Cochleates in Breast Cancer Therapy

“…Caco-2 cell line is widely used as an in vitro model for evaluating oral drug absorption (23,(51)(52)(53)(54). The medium used in Caco-2 transport in our experiments PG/DMEM (60%/ 40%) was also tested, and Caco-2 cell viability of the medium was found to be 77.4%.…”

“…Therefore, these systems were developed for oral administrations. Caco-2 cell line has been used as a model in absorption studies (23). Therefore, permeability experiments were performed using caco-2 cell lines to understand how formulations delivered raloxifene through biological membranes.…”

Lipids and inorganic nanoparticles in oral insulin delivery

“…The liposomal composition, EE, rate of drug release from lipid bilayers, size and surface charge are all important factors in successful liposomal drug delivery [28]. Degim et al have reported a signifi cant reduction in BGLs in diabetic rats on oral administration of liposomal insulin [29]. Further investigations with liposomes containing insulin in rats and dogs showed reduction in BGLs.…”