AN EVALUATION OF MICROCRYSTALLINE CELLULOSE AND LACTOSE EXCIPIENTS USING AN INSTRUMENTED SINGLE STATION TABLET PRESS

The objective of this study was to evaluate the effects of microcrysta lline cellulose of two particle sizes from two suppliers at two concen tration levels, in combination with anhydrous lactose or Fast-Flo lact ose on various properties of hydrochlorothiazide tablets. The powder b lends before compression were evaluated for flow, density and compress ibility. Tablets were compressed at three hardnesses and evaluated for friability, disintegration and hydrochlorothiazide dissolution. Powde r blends containing Fast-Flo lactose exhibited a flow rate predicted t o be sufficient for high-speed tableting whereas only when anhydrous l actose was used with the larger particle size microcrystalline cellulo se was the same degree of flowability obtained. Density was affected b y the concentration of microcrystalline cellulose. Fast-Flo lactose ma rkedly increased density at the lower level of microcrystalline cellul ose concentration. No difference was found in blend compressibility as a result of microcrystalline cellulose particle size or supplier sour ce at medium to high tablet hardness levels, however, anhydrous lactos e blends were more compressible than Fast-Flo lactose blends. At all h ardness levels, tablets from all blends exhibited excellent friability . In most instances, tablet disintegration seemed to be more rapid whe n Fast-Flo lactose was present. Hydrochlorothiazide dissolution from a ll tablets easily met USP specifications. The microcrystalline cellulo se from the two sources are interchangeable within particle size class ification. Anhydrous lactose is more compressible than Fast-Flo lactos e but Fast-Flo lactose is more flowable and its use results in more ra pid drug dissolution at the higher microcrystalline cellulose levels.