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 microcrystalline cellulose of two particle sizes from two suppliers at two concentration levels, in combination with anhydrous lactose or Fast-Flo lactose on various properties of hydrochlorothiazide tablets. The powder blends before compression were evaluated for flow, density and compressibility. Tablets were compressed at three hardnesses and evaluated for friability, disintegration and hydrochlorothiazide dissolution. Powder blends containing Fast-Flo lactose exhibited a flow rate predicted to be sufficient for high-speed tableting whereas only when anhydrous lactose was used with the larger particle size microcrystalline cellulose was the same degree of flowability obtained. Density was affected by the concentration of microcrystalline cellulose. Fast-Flo lactose markedly increased density at the lower level of microcrystalline cellulose concentration. No difference was found in blend compressibility as a result of microcrystalline cellulose particle size or supplier source at medium to high tablet hardness levels, however, anhydrous lactose blends were more compressible than Fast-Flo lactose blends. At all hardness levels, tablets from all blends exhibited excellent friability. In most instances, tablet disintegration seemed to be more rapid when Fast-Flo lactose was present. Hydrochlorothiazide dissolution from all tablets easily met USP specifications. The microcrystalline cellulose from the two sources are interchangeable within particle size classification. Anhydrous lactose is more compressible than Fast-Flo lactose but Fast-Flo lactose is more flowable and its use results in more rapid drug dissolution at the higher microcrystalline cellulose levels.