Polyanhydride carriers for controlled release

Many model formulations of polyanhydrides have been tested both in vitro and in vivo. The delivery schemes that polyanhydrides have been 

BCNU-Loaded Polyanhydride Discs for Treatment of Glioblastoma Multiforma 

The encapsulation and release of l,3-bis(2-chloroethyl)nitrosourea (BCNU) in P(CPP-SA) 20 80 wafers was the first implantable controlled release device based on polyanhydrides that was FDA-approved and marketed (Gliadel ) (Chasin et al., 1988). BCNU was encapsulated by two techniques, trituration and co-dissolution, resulting in different release profiles (Chasin et al., 1990, 1991). The triturated samples released faster than those prepared by co-dissolution, presumably due to more homogeneous loading in the samples prepared by co-dissolution. 

Jiang and Zhu (2000) and Qiu and Zhu (2001) have reported the fabrication of multilayered devices composed of stacks of compression-molded disks of alternating compositions. One type of disk is either P(SA-EG) or P[SA-co-TMAgly)-Z -EG] and the other is a pH-sensitive, protein-loaded blend of, for example, poly(methacrylic acid) and polyethoxazoline. The release of model proteins, myoglobin, bovine serum albumin, and FITC-dextran, and compounds such as brilliant blue have been studied and pulsatile release profiles have been demonstrated (Jiang and Zhu, 2000 Qiu and Zhu, 2001). 

Erdmann et al. (2000) report the fabrication of devices for the localized delivery of salicylic acid from the poly(anhydride-co-ester)s mentioned in Section II.C. A unique feature of this drug delivery system is that the drug compound is part of the polymer backbone. Devices were implanted intraorally and histopathology was reported (Erdmann et al., 2000). Chasin et al. (1990) review fabrication and testing of implantable formulations for other drugs including angiogenesis inhibitors for treatment of carcinomas and bethanechol for the treatment of Alzheimer s disease. 

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