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This article deals with the in vivo evaluation of a new class of synthetic polypeptides, the poly[(tert-butyloxycarbonylmethyl) glutamates], POMEG, as an injectable or implantable drug delivery system. Three different polymers, varying in their degree of esterification, were extruded either with or without progesterone, and finally implanted in rats up to 14 days. Histologic evaluation of the implant sites show evidence of the good biocompatibility of these polymers. In addition, the description of their in vivo behavior, based on microscopic observation of the implanted POMEG rods, enables one to appreciate their potential as a drug delivery system for short- or long-term therapy.

A novel method of synthesizing a thiol-terminated poly(Gg1utamic acid)" (PLGA) is reported. Synthesis of this compound is accomplished with the aid of a solid phase support. The procedure consists of first preparing aminoethyl disulfide-functionalized silica, glass or polystyrene solid supports. The support thus prepared is then reacted with ester-protected y-benzyl-Gglutamate or y-piperonyl-Gglutamate N-carboxyanhydride (NCA) to obtain the conjugated poly(y-ester-Gg1utamate)-support. Then the protected ester group is acidolyzed by adding hydrobromic acid or trifluoroacetic acid (TFA). Finally, the disulfide bond of the resulting acid is cloven by reacting it with mercaptoethanol thus producing the desired end product, the thiol-terminated poly(Gg1utamic acid) (yield 64%). ZUSAMMENFASSUNG:Es wird ein neues Verfahren fur die Herstellung von Polyaminosauren mit reaktiver Thiol-Endgruppe (monotelechelische Polyaminosauren) beschrieben. Poly(Lg1utaminsaure) mit einer Thiol-Endgruppe wurde uber mit Aminoethyldisulfid funktionalisierte Glas-oder Polystyroltrlgermaterialien hergestellt. Das Polymere wird auf das feste Tragermaterial aufgepfropft und, nach Entfernung der Esterschutzgruppe, als 2-(Poly-Lglutamino)ethanthiol durch Thiolyse der Disulfid-Bindung in die Lijsung freigesetzt. Eine 64proz. Ausbeute an Poly(Gg1utaminsaure) mit Thiol-Endgruppe wurde erhalten, wenn y-Piperonyl-N-carboxy-Gglutamat-anhydrid als Monomeres auf porosem Glas als Tragermaterial benutzt wurde. a IUPAC name: a-hydro-o-(2-mercaptoethyl)amino-poly(sodium imino-[ 1-(2-carboxylatoethyl)-2-oxo]ethylene~ 0