Coupling of naltrexone to biodegradable poly(alpha-amino acids).
Coupling of naltrexone to biodegradable poly(alpha-amino acids).
复制标题
纳曲酮与可生物降解的聚（α-氨基酸）的偶联。
DOI：
10.1023/a:1016493103302
复制
发表时间：
1987
影响因子：
3.7
通讯作者：
Kim,SW
中科院分区：
文献类型：
--
作者：
Negishi,N;Bennett,DB;Cho,CS;Jeong,SY;VanHeeswijk,WA;Feijen,J;Kim,SW
The narcotic antagonist naltrexone (I) was modified at the 3 and 14 hydroxyl positions and covalently coupled to a biodegradable poly(α-amino acid) backbone through a labile bond. Selective acetylation ofIwith acetic anhydride gave naltrexone-3-acetate (II), which was subsequently succinoylated to naltrexone-3-acetate-14-hemisuccinate (III) with succinic anhydride. The polymeric backbone chosen for initial coupling experiments was poly-N5-(3-hydroxypropyl)-L-glutamine (PHPG). The side-chain hydroxyl functionality permitted covalent bonding ofIIIthrough an ester linkage. Hydrolysis of covalently bound drug to give naltrexone or its derivatives (IIandIII) should be much slower than diffusion of drug through the polymer matrix. While hydrolysis of naltrexone from the polymer side chain is first order, release of drug from the matrix can be zero order due to the geometry of the device and the physical and chemical interactions between naltrexone and the polymer matrix.In vitrostudies of PHPG–naltrexone conjugate in disk form did not show constant release because of the hydrophilic nature of the polymer backbone and the changing local chemical environment upon hydrolysis of drug–polymer linkages. The conjugated system was made more hydrophobic by coupling drug to copolymers of hydroxypropyl-L-glutamine (HPG) and L-leucine. Conjugates ofIIIcoupled with copoly(HPG-70/Leu-30) demonstrated a nearly constant, but slightly declining release rate of naltrexone and its derivatives for 28 daysin vitro.
