Eperisone hydrochloride is widely used for the treatment of plasticity to relieve muscle stiffness and back pain. However, oral eperisone has a very low bioavailability and short muscle relaxant activity, because of the profound intestinal first-pass metabolism. To improve the efficacy and compliance of eperisone, we designed a new dosage form, a transdermal patch, and evaluated the efficacy of the eperisone patch with the muscle relaxant activity of rats. The muscle relaxant activity was assessed by the measurement of forelimb grip strength and hanging test in rats. The transdermal patch of eperisone showed significantly enhanced muscle relaxant activity at 0.5 1.5 and 3 cm²/200 g rat (1.39, 4.17 and 8.33 mg of eperisone hydrochloride/kg, respectively) in a dose-dependent manner and the effects lasted over 24 h. Even though oral eperisone hydrochloride showed significant muscle relaxant activity at 12.5, 25 and 50 mg/kg in a dose-dependent manner, the activity lasted only 1 or 2 h after administration. These results suggest that eperisone as transdermal patch form showed efficient absorption with more potent and longer-lasting muscle relaxant activity than oral solution. The transdermal patch form of eperisone will increase the efficacy and compliance in the clinical use of eperisone.

In the Fenton reaction, degradation and dechlorination are directly affected by the concentrations of hydrogen peroxide and Fe 3+ . Although there is considerable research on the biodegradation of chlorinated compounds combined with the Fenton reaction, the kinetics of degradation and dechlorination of the reaction, with various concentrations of hydrogen peroxide and Fe 3+ , have been rarely investigated. Therefore, we investigated the degradation and dechlorination of PCE with various concentrations of hydrogen peroxide and Fe 3+ . The initial concentration of PCE (10 µM) decreased from a value of 8.9 µM (with 0.1 mM of hydrogen peroxide and 5 mM of Fe 3+ ) to 1.1 µM (with 10 mM of hydrogen peroxide and 5 mM of Fe 3+ ); the respective values for chloride ions produced were 0.9 and 21.6 µM. Also, the initial 10 µM of PCE decreased from 8.9 (with 0.1 mM of Fe 3+ and 5 mM of hydrogen peroxide) to 2.2 µM (with 10 mM of Fe 3+ and 5 mM of hydrogen peroxide); the respective chloride ions produced were 0.7 and 14.5 µM. The logarithmic correlations between the degradation and dechlorination coefficients were 0.7682 and 0.7834 for concentrations of hydrogen peroxide and Fe 3+ , respectively. Both coefficients were used, from all possible cases, to derive six models which displayed both the ratio of degradation and dechlorination and the hydrogen peroxide and Fe 3+ concentrations. The dechlorination of PCE could then be predicted with the model obtained by the coefficient with the concentration of hydrogen peroxide and Fe 3+ . The models could be applied to various Fenton reactions for optimization of degradation or dechlorination, such as biodegradation of PCE which is scarcely degraded by aerobic bacteria.