Abstract
In order to examine the function of a wax matrix system as a barrier for the controlled release of oral dosage forms, reservoir devices were prepared and dissolution tests were conducted. The permeability coefficients of isoniazid through wax matrix layers consisting of various proportions of α-lactose monohydrate and hydrogenated castor oil were determined coincidently with the penetration rate constants of water into the wax matrix layers. To elucidate the barrier function relating to control of the drug release rate, dry-coated tablets in which the outer shell was formed with the wax matrix system were prepared. The dissolution behavior of isoniazid from the dry-coated tablets coincided with the simulation result calculated using the obtained permeability coefficient and penetration rate constant.
