Bioadhesive fluorescent microspheres as visible carriers for local delivery of drugs. II: Uptake of insulin-loaded PCEFB/PLGA microspheres by the gastrointestinal tract.
Uptake of novel inherently fluorescent microspheres composed of a luminescent polyanhydride, poly[p-(carboxyethylformamido)-benzoic anhydride] (PCEFB), and poly(lactide-co-glycolide) (PLGA) (2:1, weight ratio) by the gastrointestinal tract was evaluated by fluorescent microscopy. Oral efficiency of the incorporated insulin also was determined by measuring reduction of plasma glucose levels after feeding diabetic rats with a single dose of the microspheres. We found that PCEFB/PLGA microspheres could adhere to the intestinal epithelium and traverse the absorptive cells. A large number of the spheres were observed in spleen, whereas few were detected in liver within the evaluated period of time. Apparent reduction of the plasma glucose levels was observed over a span of 6 h postfeeding. The unique properties of the delivery system such as biodegradability, bioadhesivity, and inherently luminescent characteristics render it an ideal "visible" tracer for monitoring oral fate of polymeric microspheres.
Li
Y
Y
Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, China.
Jiang
H L
HL
Jin
J F
JF
Zhu
K J
KJ
D000269:Adhesives / Q000008:administration & dosage / Q000032:analysis / Q000378:metabolism; D000818:Animals; D001565:Benzoates / Q000008:administration & dosage* / Q000032:analysis / Q000378:metabolism; D004337:Drug Carriers / Q000008:administration & dosage / Q000032:analysis / Q000378:metabolism; D016503:Drug Delivery Systems / Q000379:methods*; D005453:Fluorescence; D041981:Gastrointestinal Tract / Q000187:drug effects* / Q000378:metabolism; D007328:Insulin / Q000008:administration & dosage* / Q000032:analysis / Q000378:metabolism; D019344:Lactic Acid / Q000008:administration & dosage* / Q000032:analysis / Q000378:metabolism; D008863:Microspheres; D011100:Polyglycolic Acid / Q000008:administration & dosage* / Q000032:analysis / Q000378:metabolism; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000008:administration & dosage* / Q000032:analysis / Q000378:metabolism; D051381:Rats; D017982:Receptors, Biogenic Amine
D000269:Adhesives; D001565:Benzoates; D004337:Drug Carriers; D007328:Insulin; D011108:Polymers; D017982:Receptors, Biogenic Amine; C027604:norsynephrine receptor; C469869:poly(p-(carboxyethylformamido) benzoic anhydride); D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid