Improvement On The Preparation Of Thiamazole Hydrogel Patch And Study On Its Influencing Factors

Thiamazole is the principal drug which is used to treat hyperthyroidism. But its oral preparation can induce a series of adverse effects. Thiamazole hydrogel patch can avoid first-pass effect and reduce the adverse effects, In addition, when compared with the commercial ointments, it might reduce the frequency of administration and are easy to apply to skin. In this work, the preparation process of thiamazole hydrogel patches were explored and the relevant experimental methods were intestigated. The main results are as follows:(1) When compared with HPLC method, UV method for determining the concentration of drug in thiamazole hydrogel patch can avoid the damage of water-soluble polymer to the HPLC column, and the operation is simpler. The results showed that it is a method with a good relationship in the range of 1.004~7.028μg/mL (r = 0.9999) and high recovery of 99.92% (RSD =0.39%).(2) In order to avoid drug release action which is induced by the swelling behavior of the gel matrix of the patch in water, Franz diffusion cells were used to investigate the in vitro release degree of the patches, and the method was constructed.(3) The molding conditions of the thiamazole hydrogel patches were investigated and screened. The results showed that all the patches had high adhesive forces and had no difference in permeation ability, when the patches were molded at 40℃for 2 h, at 60℃for 1 h and at room temperature for 12 h, respectively.(4) The adhesive force and in vitro release of the patches which with the matrix thicknesses of 1.15, 1.65 and 2.15 mm, respectively, were investigated. The results showed that matrix thickness had no influence on adhesive force of the patches, and the release rates slightly decreased with the increase of the thickness. The in vitro releases of all the patches were in accord with Higuchi equation and all the drug was released in 24 h.(5) The investigation on the in vitro permeation ability of the patches containing 10, 30 and 60 mg of drug showed that the permeation of durg from all the pathes accorded with the zero-order kinetic, and the penetration rates were increased with the increase of the concentrations of drug. (6) The patches were stored at tungsten lamp (4500 LX), high temperature (40℃) and high moisture (RH 92.5%), respectively. The results showed that the patches were sensitive to the temperature and should store at a relatively low temperature.