title: 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.
authors.affiliation: Reliance Life Sciences, Industrial Biotechnology, Dhirubhai Ambani Life Sciences Centre, Navi Mumbai, India.
authors.forename: Raghavendra C
authors.initials: RC
authors.lastname: Mundargi
authors.forename: Vidhya
authors.initials: V
authors.lastname: Rangaswamy
authors.forename: Tejraj M
authors.initials: TM
authors.lastname: Aminabhavi
mesh_terms: D000284:Administration, Oral; D000704:Analysis of Variance; D000818:Animals; D001682:Biological Availability; D006863:Hydrogen-Ion Concentration; D007004:Hypoglycemic Agents / Q000008:administration & dosage*; D007328:Insulin / Q000008:administration & dosage*; D008297:Male; D008863:Microspheres; D010316:Particle Size; D011109:Polymethacrylic Acids / Q000008:administration & dosage*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar
chemical_list: D007004:Hypoglycemic Agents; D007328:Insulin; D011109:Polymethacrylic Acids; C038300:methylmethacrylate-methacrylic acid copolymer