Insulin-Loaded Microcapsules for In Vivo Delivery

Abstract

Microencapsulation of insulin has been difficult, due to the high sensitivity of insulin to the harsh conditions that can occur during the microencapsulation process. We have developed a method of preparing insulin-loaded microcapsules by using a monoaxial ultrasonic atomizer to form microdroplets of insulin in aqueous solution surrounded by poly(lactic-co-glycolic acid) (PLGA) solution. Administration of these insulin-loaded microcapsules to type 1 diabetic rats maintained plasma insulin concentrations for 30 days, due to the sustained insulin release properties of the microcapsules. In contrast, plasma insulin concentrations after subcutaneous injection of insulin solution reached near zero levels within 2 days. Insulin solution showed only an immediate pharmacological effect, with no reduction of glycemia after 3 days, whereas insulin-loaded microcapsules maintained blood glucose levels at 100-200 mg/dL for 55 days. Molecular imaging using fluorescein isothiocyanate (FITC)-insulin-loaded microcapsules showed in vivo sustained release of the FITC-insulin in microcapsules. Using insulin-loaded microcapsules, we observed inflammation only immediately after injection, indicating that the rats adapted to long-term insulin release. In conclusion, insulin-loaded microcapsules may reduce nonrepetitive insulin administration and show sustained pharmacological performance.

Nanodiamond–insulin complexes as pH-dependent protein delivery vehicles

“…Within these instruments, fully programmable and independent systems capable of delivering the proper amount of drugs at a suitable time were capable of mimicking naturally occurring biologically processes [29]. Poly(lactic-co-glycolic acid) (PLGA)-based shells with encapsulated insulin have also been explored for the sustained release of insulin and maintained blood glucose levels [30]. The oral delivery of dextran sulfate/chitosan-based nanoparticles has also been explored in diabetic rats to increase pharmacological availability [31].…”

Novel noninvasive techniques in management of diabetes

“…Study reveals maintained BGLs at 100-200 mg/dL for 55 days. [81] In another study clayton prepared encapsulated islets of Langerhans in sodium alginate and poly-l-lysine to form the capsules, which has promising approach in the treatment of type 1 diabetic patient's. Over 90% of the entrapped insulin released after 3 days.…”

Preparation of exenatide-loaded linear poly(ethylene glycol)-brush poly(L-lysine) block copolymer: potential implications on diabetic nephropathy

“…2 However, exenatide therapy is limited due to its short plasma half-life of 2.4 h and, thus, dosing is very difficult and frequent injections are required, which are inconvenient for patients and result in low compliance. 3 Considerable interest has been generated over the past few decades in the development of effective protein-delivery systems, such as hydrogels, [4][5][6][7][8][9] polymeric nanoparticles, [10][11][12][13][14][15][16] nano-or microcapsules, [17][18][19] and…”