Release of BSA from poly(ortho ester) extruded thin strands.
A solventless procedure was used where powdered polymer and micronized protein were intimately mixed and then extruded into 1 mm strands that were cut to the desired length. The polymers used were poly(ortho esters) specifically designed to allow extrusion in the neighborhood of 70 degrees C. At these temperatures many proteins maintain activity in the dry state. In vitro erosion and BSA release results indicate that after a fairly long lag-time, BSA release and polymer erosion occur concomitantly indicating an erosion-controlled process. The lag-time could be eliminated by the addition to the mixture prior to extrusion between 1 and 5 wt% poly(ethylene glycol) or its methoxy derivatives. The lag-time could also be eliminated by using an AB-block copolymer where A is poly(ortho ester) and B is poly(ethylene glycol).
University of Geneva, School of Pharmacy, 30 Quai E. Ansermet, CH1211 4, Geneva, Switzerland.
A
A
Rothen-Weinhold
K
K
Schwach-Abdellaoui
J
J
Barr
S Y
SY
Ng
H R
HR
Shen
R
R
Gurny
J
J
Heller
D003460:Crystallization; D016503:Drug Delivery Systems; D005079:Excipients; D016650:Fluorescein-5-isothiocyanate; D005456:Fluorescent Dyes; D008970:Molecular Weight; D011108:Polymers / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D013816:Thermodynamics
D005079:Excipients; D005456:Fluorescent Dyes; D011108:Polymers; C401107:poly(ortho ester); D012710:Serum Albumin, Bovine; D016650:Fluorescein-5-isothiocyanate