A new biodegradable pasty-type copolymer of l-lactic acid and δ-valerolactone with relatively low molecular weight for application in drug delivery systems
1989; Elsevier BV; Volume: 10; Issue: 3 Linguagem: Inglês
10.1016/0168-3659(89)90079-5
ISSN1873-4995
AutoresHironobu Fukuzaki, Masaru Yoshida, Asano Masaharu, Minoru Kumakura, Tooru Mashimo, Hisako Yuasa, Kyoichi Imai, Hidetoshi Yamanaka, K UMEKO, Keiji Suzuki,
Tópico(s)Biopolymer Synthesis and Applications
ResumoCopolymers of l-lactic acid (LA) and δ-valerolactone (VL) with a number-average molecular weight (M̄n) of 1500–2600 were developed as biodegradable carriers for drug delivery. Copolymers were synthesized by direct copolycondensation in the absence of a catalyst. Depending on the mol% of l-lactic acid residues, three different morphologies are obtained: solid state (100-80 mol%), pasty state (70-30 mol%), and waxy state (15-0 mol%). The degradation of the copolymer was markedly influenced by Rhizopus delemer lipase. The rate of degradation of the pasty copolymer in the presence of the lipase is much faster than that for the solid or the waxy Copolymers. A nitrogen mustard derivative of estradiol-17β, Estramustine, was incorporated into a pasty-type copoly(LA/VL, 70/30 mol%) with M̄n = 2500. The system was completely degraded in vivo (rat) 5 weeks after insertion. A pharmacological effect on the prostates of rats was observed during a period of 5 weeks.
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