PubMed · 15423995
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1950. [Tablet presses].. https://pubmed.ncbi.nlm.nih.gov/15423995/
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Analysis of the entire release process of the wax matrix tablet was examined. Wax matrix tablet was prepared from a physical mixture of drug and wax powder to obtain basic or clear release properties. The release process began to deviate from Higuchi equation when the released amount reached at around the half of the initial drug amount. Simulated release amount increase infinitely when the Higuchi equation was applied. Then, the Higuchi equation was modified to estimate the release process of the wax matrix tablet. The modified Higuchi equation was named as the H-my equation. Release process was well treated by the H-my equation. Release process simulated by the H-my equation fitted well with the measured entire release process. Also, release properties from and through wax matrix well coincident each other. Furthermore, it is possible to predict an optional release process when the amount of matrix and composition of matrix system were defined.
To obtain basic and clear release properties, wax matrix tablets were prepared from a physical mixture of drug and wax powder at a fixed mixing ratio. Properties of release from the single flat-faced surface, curved side surface, and/or whole surface of the wax matrix tablet were examined. Then tortuosity and the applicability of Higuchi's square-root time law equation were examined. The Higuchi equation well analyzed the release processes of different release manners. However, the region fitted to the Higuchi equation differed with the release manner. Tortuosity obtained with release from the single flat-faced surface and curved side surface was comparable with that obtained with the release from a reservoir device tablet, whereas tortuosity obtained with release from the whole surface was larger. As the wax matrix tablets were prepared at a fixed mixing ratio, their internal structures should be similar. Therefore changes in the matrix volume or volume fraction with release were examined, and an extra volume where dissolved drug stray becomes large with release time in the case of release from the whole surface. These factors should be taken into account for evaluation of applicability and release properties. Furthermore, the entire release process should be analyzed using a combination of the square-root time law and other suitable equations in accordance with release manner or condition.
Talc is defined as a crystalline structure characteristic of lamellar structures. Antisticking power varies according to the talc considered. Besides chemical properties, it is necessary to assess physical properties related to functionality. It is difficult to define the physical properties of talc implicated in its antisticking power. In this work, we characterized different talcs and then evaluated their performances in reducing sticking in tablet manufacturing. We compared talcs before and after delamination which is a way to obtain talcs with different physical characteristics. Granulometric analysis was carried out by laser diffractometry using a method which made it possible to assess the mean thickness of the lamellar particles. We defined a functionality assay on a single punch press to assess the antisticking power of talcs. The different talcs tested possess a very variable antisticking power towards Avicel PH 102. They present different basal dimensions and particle thickness. The force necessary to detach tablets from the punch surface varies according to the functioning time of the tablet machine, the percentage of talc and the basal dimension of talc.