title: Development of β-cyclodextrin-based sustained release microparticles for oral insulin delivery.
abstract: Polymeric microparticles have been previously demonstrated to deliver various therapeutic agents efficiently to targeted regions by protecting the drug from harsh gastric milieu of the gastrointestinal tract. In this study, we investigated the hypoglycemic effect of β-cyclodextrin polymeric insulin microparticles in diabetic rats via the oral route of administration. β-cyclodextrin microparticles were prepared by a unique one-step spray-drying technique and stabilized by incorporating enteric retardant polymers in the formulation. The insulin-loaded microparticles had a mean size of 0.8 ± 0.25 μm with a zeta potential of 3.57 + 0.62 mV. As seen with the chromatographic analysis, the drug content in the microparticles was determined to be 94.9 ± 2.77%. RAW macrophage cells showed greater than 80% viability after 24 h of incubation with the insulin and blank microparticles. For the in vitro release study, the microparticles were able to protect the insulin in gastric fluid where no significant release was detected, followed by only 50% release in intestinal fluid for the first 8 h of the study. This was seen to correlate with the in vivo data where 50% glucose inhibition was seen after 8 h of oral administration in diabetic rats. This data suggest that the oral insulin microparticles were able to reduce glucose levels in disease conditions and would be a favorable route of administration to patients as an alternative to daily subcutaneous injections.
authors.affiliation: McWhorter School of Pharmacy, Samford University , Birmingham, AL , USA .
authors.forename: Bernadette
authors.initials: B
authors.lastname: D'Souza
authors.forename: Tuhin
authors.initials: T
authors.lastname: Bhowmik
authors.forename: Mohammad Nasir
authors.initials: MN
authors.lastname: Uddin
authors.forename: Carl
authors.initials: C
authors.lastname: Oettinger
authors.forename: Martin
authors.initials: M
authors.lastname: D'Souza
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D003692:Delayed-Action Preparations / Q000008:administration & dosage / Q000493:pharmacokinetics; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000188:drug therapy*; D004305:Dose-Response Relationship, Drug; D016503:Drug Delivery Systems / Q000379:methods*; D007004:Hypoglycemic Agents / Q000008:administration & dosage / Q000493:pharmacokinetics; D008297:Male; D008863:Microspheres; D051381:Rats; D017207:Rats, Sprague-Dawley; D047392:beta-Cyclodextrins / Q000008:administration & dosage* / Q000493:pharmacokinetics
chemical_list: D001786:Blood Glucose; D003692:Delayed-Action Preparations; D007004:Hypoglycemic Agents; D047392:beta-Cyclodextrins; C031215:betadex
keywords: Cyclodextrin; insulin; microparticles; oral delivery; spray drying; sustained release