Poly(vinyl alcohol)-Salicylic Acid Conjugate: Synthesis and Characterization

Abstract

The poly meric system containing hydrolysable ester bonds linked to salicy lic acid was synthesized for controlled drug release. Po ly(vinyl alcohol) (PVA) functionalized with chlo roacetate groups was obtained by reaction of PVA with chloroacetyl chloride using the N,N-d imethylacetamide/5% lithiu m chloride system as solvent and pyridine as catalyst. The degree of substitution was calculated fro m the chloride content and ranged from 37.8 to 98.9 mol%. The coupling of salicylic acid to PVA functionalized with chloroacetate groups was carried out by the reaction with between PVA and the sodium salt of salicylic acid. The structures of chloroacetylated PVA and PVA-salicylic acid conjugates were determined by means FTIR, 1 H-NM R and 13 C-NM R spectra. The hydrolysis in the heterogeneous system of PVA-salicylic acid conjugates were performed in buffer solutions (pH 7.6 and 8.5) at 37℃. Detection of hydrolysis by UV spectroscopy showed that released the drug, can by achieved by the hydrolysis of the ester bond between the drug and the poly meric carrier. The release profiles indicated that the release of the drug (sodium salicy late) fro m tablets was dependent on hydrophilic character of conjugate and the pH of the buffer solution.

Fluorescent microspheres of poly(ethylene glycol)–poly(lactic acid)–fluorescein copolymers synthesized by Ugi four‐component condensation

“…These results were in close agreement with those found in the literature, in which the yields were over 60% for end‐functionalized PLA from an ROP with Sn(Oct) 2 as the initiator and nine different primary alcohols as coinitiators . Even with water as a coinitiator in the presence of Sn(Oct) 2 as an initiator, yields of over 80% were reported …”

Synthesis and Characterization of Complexes of Remodulated Polyvinyl Alcohol Conjugates

“… Fourier Transform Infra-Red Spectroscopy FTIR characterization of RPVA and CMPVA is found to be important for investigation of polymer structure that provides information about the complexation and interactions between the various constituents in the polymeric films. Each type of bond has a different natural frequency of vibration, so the identification of an absorption peak in the vibration portion of the infrared region will give a specific type of bonding [17]. The FTIR spectra for RPVA and CMPVA are shown in Figure 1 to 2 and observed vibrational frequencies are given in Table- In CMPVA signal showed at 4.50 ppm ( labelled a) was attributed to hydroxyl proton triads of mm, mr, rr from high to low frequency, whist the signals labeled b and c were ascribed to the PVA polymer backbone (methine and methylene protons respectively ).…”

Hyperbranched poly (ester) s for delivery of small molecule therapeutics

“…The time‐release of salicylic acid would enhance the duration of its effectiveness while minimizing skin irritation. Due to the problems associated with the administration of salicylic acid derivatives, much effort has been directed toward the development of biodegradable polymeric drug formulations for the controlled release of these compounds . This work describes the conjugation of salicylic acid to a glycerol, AA HBPE, and its timed release from the HBPE conjugate through enzyme‐catalyzed hydrolytic degradation.…”