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Antiinflammatory polymer‐bound steroids for topical applications. I. Synthesis and characterization
Author(s) -
Khue Nguyen Vu,
Galin J. C.
Publication year - 1985
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1985.070300705
Subject(s) - copolymer , polymer chemistry , monomer , dimethylacetamide , chemistry , polymer , hydroxymethyl , reactivity (psychology) , acrylamide , nuclear chemistry , organic chemistry , medicine , alternative medicine , pathology , solvent
Covalent binding of hydrocortisone and dexamethasone to hydrophylic biocompatible macromolecular carriers through hydrolizable carbonate linkage was investigated according to two complementary strategies. (a) Radical copolymerization of hydrocortisone‐ 21 C‐vinylcarbonate with N ‐vinylpyrrolidone (NVP,60°C), or N ‐[tris(hydroxymethyl)methyl]acrylamide (THMMA, 50°C) in dimethylacetamide solution: In spite of a nearly zero reactivity ratio for the steroid monomer which behaves as a degradative transfer agent— C T ∼ 5.7 × 10 −2 and 6.8 × 10 −3 for NVP and THMMA, respectively–this process may afford fairly high molecular weight polymers ( M̄ w ≃ 10 4 –10 5 ) with high enough hydrocortisone content (0.03–0.10 mole.fraction). (b) Condensation of the hydrocortisone or dexamethasone‐ 21 C‐chloroformates onto poly(oxyethylene glycol) ( M̄ n = 6220) or hydroxypropylcellulose (HPC, M̄ w = 1.35 × 10 5 ) in tetrahydrofuran solution (30°C): This straightforward process is of low efficiency (yields >50%), and only HPC derivatives show good chemical homogeneity.