Sustained release of insulin by double-layered implant using poly(D,L-lactic acid).
This report describes the advantage of double-layered implants using low molecular weight poly(DL-lactic acid) in the sustained release of insulin. The double-layered implant consisted of a polymer matrix containing insulin and a polylactic acid layer which was coated partially on one of the surfaces of the insulin:polymer matrix. The double-layered implants were compared with single-matrix implants from the standpoint of the in vitro dissolution test and in vivo performance. In vitro release rates were controlled by changing the amount of poly(DL-lactic acid) used in the polymer layer. In an in vivo test using diabetic animals, the double-layered implants provided a sustained release of insulin for 19 d, as judged by the changes in blood glucose levels and serum insulin levels after the subcutaneous implantation.
Tsukuba Research Laboratories, Eisai Company, Ltd., Ibaraki, Japan.
I
I
Yamakawa
M
M
Kawahara
S
S
Watanabe
Y
Y
Miyake
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001835:Body Weight; D002851:Chromatography, High Pressure Liquid; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy; D004343:Drug Implants; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D007773:Lactates / Q000008:administration & dosage / Q000494:pharmacology*; D019344:Lactic Acid; D008297:Male; D008970:Molecular Weight; D011091:Polyesters; D011108:Polymers / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains
D001786:Blood Glucose; D004343:Drug Implants; D007328:Insulin; D007773:Lactates; D011091:Polyesters; D011108:Polymers; D019344:Lactic Acid; C033616:poly(lactide)