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.
Yamakawa
I
I
Tsukuba Research Laboratories, Eisai Company, Ltd., Ibaraki, Japan.
Kawahara
M
M
Watanabe
S
S
Miyake
Y
Y
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)