1987 年 107 巻 3 号 p. 233-237
Poly (vinyl alcohol) (PVA) gels, which may be used for the base of drug release, were prepared by a given cycle of freezing and thawing. Polymerization degree and concentration of PVA, a given cycle and temperature of freezing and thawing were discussed to obtain enough physical strength of the gel. The physical strength of the gel was evaluated in terms of penetration degree of penetrometer. Furthermore, the gel was cross-linked by glutaraldehyde for the control of the drug release. Polymerization degree and concentration of PVA to obtain enough strength of the gel were over 1000 and 6%, respectively. The physical strength of the gel was increased with increasing the cycle times, then becoming horizontal after fourth time of cycle. The optimum temperature of freezing and thawing were -30 and 20°C, respectively. The drug release of indomethacin from the gel was in agreement with a matrix model. Zero order drug release from the gel was established by cross-linking with glutaraldehyde.