Abstract
p-Methoxyphenyl methacrylate (ESMAA) was copolymerized with methacrylic acid (MAA) in dioxane solutions using azobisisobutyronitrile (AIBN) as an initiator. The compositions of the copolymers were assayed for the aromatic ester content by measuring the ultraviolet (UV)absorbance at 240 nm in dioxane. The monomer reactivity ratios r1and r2 for copolymerization of MAA(M1)and ESMAA (M2)are 1.52 and 3.01. The glass transition temperatures of MAA-ESMAA copolymers are almost equal to the weight-average values. The drug released from copolymers increases with the composition of methacrylic acid units. The releases of piroxicam from the MAA-co-ESMAA matrices containing 55 mole%MAA in pH 7.4 and 10 buffer solutions are steady for the whole release period, and release profiles matches closely to the disintegration profiles of the MAA-55 copolymer.