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Long-term release of a thiobenzamide from a backbone functionalized poly(lactic acid)
Journal article   Open access

Long-term release of a thiobenzamide from a backbone functionalized poly(lactic acid)

Tyler R Long, Amaraporn Wongrakpanich, Anh-Vu Do, Aliasger K Salem and Ned B Bowden
Polymer chemistry, Vol.6(40), pp.7188-7195
10/01/2015
DOI: 10.1039/c5py01059d
PMCID: PMC4746005
PMID: 26870159
url
http://doi.org/10.1039/C5PY01059DView
Open Access

Abstract

Hydrogen sulfide is emerging as a critically important molecule in medicine, yet there are few methods for the long-term delivery of molecules that degrade to release H sub(2)S. In this paper the first long-term release of a thiobenzamide that degrades to release H sub(2)S is described. A series of polymers were synthesized by the copolymerization of l-lactide and a lactide functionalized with 4-hydroxythiobenzamide. A new method to attach functional groups to a derivative of l-lactide is described based on the addition of a thiol to an alpha , beta -unsaturated lactide using catalytic I sub(2). This reaction proceeded under mild conditions and did not ring-open the lactone. The copolymers had molecular weights from 8 to 88 kg mol super(-1) with PDIs below 1.50. Two sets of microparticles were fabricated from a copolymer; the average diameters of the microparticles were 0.53 and 12 mu m. The degradation of the smaller microparticles was investigated in buffered water to demonstrate the slow release of thiobenzamide over 4 weeks. Based on the ability to synthesize polymers with different loadings of thiobenzamide and that thiobenzamide is a known precursor to H sub(2)S, these particles provide a polymer-based method to deliver H sub(2)S over days to weeks.
Degradation Copolymers Precursors Copolymerization Derivatives Molecular weight Microparticles Lactones

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