In-vitro evaluation of enteric coated insulin tablets containing absorption enhancer and enzyme inhibitor.
OBJECTIVE
The aim of this study was to develop an enteric coated insulin tablet formulation using polymers, absorption enhancer and enzyme inhibitor, which protect the tablets in acidic pH and enhance systemic bioavailability.


METHODS
In this study, the influence of coating by cellulose acetate hydrogen phthalate solution and chosen excipients on Glut-4 transporter translocation in C2C12 skeletal muscle cells was examined. Following the determination of optimum number of coating layers, two dissolution buffers such as 0.01 m hydrochloric acid, pH 2, and 50 mm phosphate, pH 7.4, were employed to determine the in-vitro release of insulin.


RESULTS
Insulin was protected by the coating during the dissolution process. Five (5-CL) coating layers and eight (8-CL) coating layers had minimal insulin release in hydrochloric acid, but not three (3-CL) coating layers. Glut-4 translocation in C2C12 cells was promoted by the chosen excipients. No detrimental metabolic effects were observed in these cells.


CONCLUSIONS
To date, limited studies combine the overall effectiveness of multiple excipients. Our study showed that the coated tablets have an immediate release effect in phosphate buffer. In Glut-4 translocation assay, insulin was still functional after releasing from the tablet. Such tablet formulation can be potentially beneficial to type 1 diabetes patients.
School of Pharmacy, Curtin University, Bentley, WA, Australia.
Chun Y
CY
Wong
School of Pharmacy, Curtin University, Bentley, WA, Australia.|Pharmaceutical Technology Facility, School of Pharmacy, Curtin University, Bentley, WA, Australia.
Jorge
J
Martinez
School of Pharmacy, Curtin University, Bentley, WA, Australia.|Curtin Biosciences Research Precinct, Bentley, WA, Australia.
Revathy
R
Carnagarin
School of Pharmacy, Curtin University, Bentley, WA, Australia.|Curtin Biosciences Research Precinct, Bentley, WA, Australia.
Crispin R
CR
Dass
D002021:Buffers; D002482:Cellulose / Q000031:analogs & derivatives / Q000737:chemistry; D002626:Chemistry, Pharmaceutical / Q000379:methods; D004791:Enzyme Inhibitors / Q000737:chemistry*; D005079:Excipients / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007328:Insulin / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry; D012995:Solubility; D013608:Tablets, Enteric-Coated / Q000737:chemistry*
D002021:Buffers; D004791:Enzyme Inhibitors; D005079:Excipients; D007328:Insulin; D011108:Polymers; D013608:Tablets, Enteric-Coated; D002482:Cellulose; C011708:cellulose acetate phthalate; C054416:cellulose, hydrogen phthalate
chitosan; diabetes; insulin; oral; tablet