Release from or through a Wax Matrix System. I. Basic Release Properties of the Wax Matrix System.

Abstract

To control drug release is a topic of much interest. Matrix systems were often used as one method to control drug release. Higuchi mathematically showed the drug release properties of matrix systems, 1) and numerous investigations have been carried out since then. Based on the component, matrix systems can be roughly classified into two types, i.e., polymer and wax matrix systems. Drug release from a polymer matrix is likely to be accompanied by dissolution and/or swelling of matrix layer, and the shape and size of the matrix system varies with release time. Thus polymer matrix systems involve complicated conditions. Compared with polymer matrix systems, wax matrix systems are considered to retain the initial form. To control drug release, it is important to maintain some basic properties of the matrix system. Considering the above difference, the release properties of wax matrix systems should be investigated at first.When a wax matrix system is prepared from melted granules of soluble component and wax, troublesome factors such as surface coverage and thickness of wax on the soluble component must be considered. On the other hand, when a wax matrix system is prepared using a physical mixture of soluble component and wax, basic release properties can be estimated by connecting their basic properties and simple factors.Therefore, wax matrix tablets were prepared from a physical mixture, and basic release properties were examined by the measurement of release from the single flat surface or curved side surface of the tablets. ExperimentalMaterials Isoniazid JP (INZ, Yukigousei Yakuhin Kogyo Co.) was pulverized to about 7 mm prior to use. Hydrogenated caster oil (HCO, Kawaken Fine Chemical Co.) was used as the matrix substance. 2) Preparation of Physical Mixture for Wax MatrixThe mixed weight ratio of INZ to HCO powder was fixed at 7 : 3. The appropriate amounts of INZ and HCO powder were physically mixed using an automatic mixer (type S 10, Taiyo Kagaku Kogyo Co.). Preparation of Tablets for Release from One Flat SurfaceThe amount of physical mixture was fixed at 0.50 or 1.20 g for tablets 10 or 16 mm in diameter, respectively. The physical mixture was put into a die and compressed at 1273 kg/cm 2 with flat-faced punch (model clean press correct 12 HUK, Kikusui Co., Ltd.). A tablet was placed at the center of a die of 16 or 20 mm and the appropriate amount of HCO powder was added. Then the content was compressed at 637 kg/cm 2 . Preparation of Tablets for Release from Curved Side SurfaceUsing the appropriate amount of HCO and the physical mixture of 0.50 or 1.20 g, three-layered tablets 10 or 16 mm in diameter were prepared with compression force of 1273 kg/cm 2 . Release Test A dissolution apparatus (model NTR-VS, Toyama Sangyo Co., Ltd.) coupled to a flow cell set in a double-beam spectrophotometer (model 200-20, Hitachi Ind. Co.) via a microtube pump (model MP-3, Tokyo Rikakikai Co., Ltd.) and pen recorder (model 3056, Yokogawa Electric Works, Ltd.) was used. Release measurement was carried out in 900 ml of di...

Analysis of the Release Process of Phenylpropanolamine Hydrochloride from Ethylcellulose Matrix Granules V. Release Properties of Ethylcellulose Layered Matrix Granules

“…[1][2][3][4][5] It was confirmed in previous papers that ethylcellulose (EC) matrix granules and EC layered granules showed similar release properties. 1) There are many methods for the preparation of layered granules.…”

Release from or through a Wax Matrix System. II. Basic Properties of Release from or through the Wax Matrix Layer.

“…1,3) These were isoniazid JP (INZ, Yukigousei Yakuhin Kogyo Co.) and hydrogenated caster oil (HCO, Kawaken Fine Chemical Co.). The mean diameter of INZ and HCO are 10.6 and 10.3 mm, respectively.…”

“…In the previous paper, 1) release property of wax matrix tablet prepared from a physical mixture was examined, and it was suggested that the structure of matrix was uniform threedimensionally.…”

Analysis of the Release Process of Phenylpropanolamine Hydrochloride from Ethylcellulose Matrix Granules IV.1) Evaluation of the Controlled Release Properties for in Vivo and in Vitro Release Systems

“…2,3) The release properties of the matrix system were mathematically assessed by Higuchi,4) and matrix systems have often been used as a method of controlled drug release; however, it was considered that the mathematical analysis of the release process was insufficient, because the equation can not explain the entire release process. 1,5,6) In previous papers, the release process was divided into two stages to understand the entire release process and these were analyzed using a combination of the square-root time law and cube-root law equations.…”