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.

By reacting poly(methacryloyl chloride) with 2‐hydroxyethyl methacrylate a multimethacrylate on a polymethacrylate template is obtained. Free‐radical polymerization of the multimethacrylate in dilute DMF solutions was investigated. The results obtained suggest that the polymerization process occurs along the template and results in partially ladder‐type polymers, containing unreacted double bonds. Based on the results of elemental analysis, IR, and 1H‐NMR spectra, structures of the multimethacrylate and the obtained polymer were proposed. The rate of disappearance of double bonds in the multimonomer during UV irradiation was examined. Thermogravimetric analysis of the multimethacrylate and related polymers was also performed.

The free radical copolymerization of multimethacrylate with styrene and acrylonitrile in dilute dimethylformamide solutions has been investigated. The effects of the copolymerization conditions on the content of unreacted double bonds, molecular weight, and composition of the copolymers were determined. Based on IR and 'H-NMR spectra the structures of the copolymers were confirmed. The examination of copolymerization in the presence of AIBN labeled with I4C allowed to determine the number of branching points in a macromolecule. The results show that the copolymerization process results in copolymers composed partly of ladder-type blocks and blocks of vinyl monomer units. The thermal properties of the copolymers were determined. Copolymerisation von Multimethacrylat mit VinylmonomerenDie radikalische Copolymerisation von Multimethacrylat mit Styren und Acrylnitril in verdunnter Losung wurde untersucht. Der EinfluD der Copolymerisationsbedingungen auf den Gehalt an nichtreagierten Doppelbindungen, die Molekiilmasse und die Zusammensetzung der Copolymere wurde ermittelt. Auf Basis der IRund 'H-NMR-Spektren wurde die Struktur der Copolymere bestatigt. Die Copolymerisation in Gegenwart von %markiertem AIBN ermoglichte die Bestimmung der Anzahl der Verzweigungspunkte je Makromolekul. Die Ergebnisse zeigen, daB die erhaltenen Copolymere teilweise aus Leiterpolymerblocken und aus Blocken von Vinylmonomereinheiten bestehen. Die thermischen Eigenschaften der Copolymere wurden untersucht. Scheme 1 Actr Polymeriu 42 (1991) Nr. 11 540 JANTAS: Copolymerization of multimethacrylatc with vinyl monomcrs Received A u p s t 3, 1990N-phenyl maleimide (NPMI) was copolymerized with methyl acrylate (MA), ethyl acrylate (EA), methyl methacrylate (MMA), and butyl methacrylate (BMA). The composition diagrams for the copolymerization were determined. An azeotropic monomer composition was found in the range 0.55 to 0.65 of the acrylate feed ratio for the systems MA, EA, and MMA with NPMI with a maximum initial rate ofcopolymerization at 10 mole-% acrylate, whereas neither an azeotropic composition nor a maximum rate was found with the system BMA-NPMI. High concentration of maleimide in the monomer feed affects the intrinsic viscosity negatively. Degradative chain transfer to maleimide is assumed to cause the decrease in molecular weight.

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