pH-Sensitive oral insulin delivery systems using Eudragit microspheres

Abstract

In this paper, we present in vitro and in vivo release data on pH-sensitive microspheres of Eudragit L100, Eudragit RS100 and their blend systems prepared by double emulsion-solvent evaporation technique for oral delivery of insulin. Of the three systems developed, Eudragit L100 was chosen for preclinical studies. Insulin was encapsulated and in vitro experiments performed on insulin-loaded microspheres in pH 1.2 media did not release insulin during the first 2 h, but maximum insulin was released in pH 7.4 buffer media from 4 to 6 h. The microspheres were characterized by scanning electron microscopy to understand particle size, shape and surface morphology. The size of microspheres ranged between 1 and 40 µm. Circular dichroism spectra indicated the structural integrity of insulin during encapsulation as well as after its release in pH 7.4 buffer media. The in vivo release studies on diabetic-induced rat models exhibited maximum inhibition of up to 86%, suggesting absorption of insulin in the intestine.

Keywords::

• Eudragit L100
• Eudragit S100
• microspheres
• oral delivery
• insulin
• pH-sensitive

Acknowledgements

The authors gratefully acknowledge the encouragement and support of Reliance Life Sciences Pvt. Ltd, in carrying out the research work

Declaration of interest

The authors declared no conflict of interest.