Aminosalicylate‐based biodegradable polymers: Syntheses and in vitro characterization of poly(anhydride‐ester)s and poly(anhydride‐amide)s

Abstract

Poly(anhydride‐ester)s and poly(anhydride‐amide)s derived from both 4‐ and 5‐aminosalicylate acids (4‐ and 5‐ASA) were synthesized and characterized by physicochemical methods. Thermal and solubility characteristics directly correlated to the polymer backbone composition; polymers based on 5‐ASA had greater solubilities in organic solvents than polymers based on 4‐ASA, and the poly(anhydride‐ester)s thermally decomposed at temperatures nearly 100 °C higher than the corresponding poly(anhydride‐amide)s. The polymers were self‐contained, controlled‐release systems that combine the drug and controlled‐release mechanism into the polymer backbone. The erosion and degradation characteristics of the polymers were measured in physiologically relevant media. All polymer matrices fully degraded in media buffered to pH 7.4, whereas in acidic media (pH 1.2), all polymer matrices maintained greater than 50% mass over a 90‐day time period. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3667–3679, 2003

Polyactives: controlled and sustained bioactive release via hydrolytic degradation

“…SA diacid was then activated using excess acetic anhydride and subsequently polymerized at elevated temperatures under vacuum, ultimately acquiring a bioactive-linker-bioactive repeat unit (Figure 2B). This synthetic methodology is adaptable to a wide variety of salicylates such as aminosalicylates, 31, 61 iodinated salicylates, 62 diflunisal and salsalate among others. 30 …”

Polyanhydrides

“…Aminosalicylic acid is a useful bioactive agent for infl ammatory bowl disease and the drug needs to be specifi cally delivered at the site of action, that is, colon. Synthesis of this category of the polymers can be carried out by usual preparation of prepolymers and then melt condensation to produce high molecular weight polymer [25] . Salicylic acid -based poly(ester -anhydride)s have also been tested for healing of long bone defects in rats with 5 -mm mid -diaphyseal defects in femurs.…”

Novel Copolyanhydrides Combining Strong Inherent Fluorescence and a Wide Range of Biodegradability: Synthesis, Characterization and in vitro Degradation

“…Mathiowitz and co‐workers found a novel class of hydrophobic, strongly bioadhesive microspheres, which are based on rapidly degradable poly(fumaric‐ co ‐sebacic anhydride) [P(FA:SA)] and could enhance oral bioavailability of bioactive agents such as proteins and DNA 6–9. Biodegradable polymeric prodrugs, with the advantages of high drug loading percent and strict correlation between polymer degradation and drug release, were synthesized by incorporating salicylic acid or aminosalicylic acid into the polymer backbones 10–12. Anseth's group designed a series of photo‐crosslinkable polyanhydride monomers which could in situ form high‐strength and surface eroding networks of complex geometries.…”