PROPERTIES OF DIRECTLY COMPRESSED PARACETAMOL TABLETS CONTAINING ALPHA – AND MICROCRYSTALLINE
Cob alpha-cellulose (CAC) was extracted from maize cobs by standard extraction procedures with a yield of 21%. Part of the CAC was partially depolymerised into cob microcrystalline-cellulose (CMCC) by hot acid treatment, yielding 90%. The CAC and CMCC were compared with Aviccl1R PI 1101 which is also microcrystalline cellulose. The mean particle sizes of CAC, CMCC and Avicelk were 58.4, 38.9, and 39.2 Dm respectively. The moisture content and sorption capacity for CAC were 3.1% and 23.4%; for CMCC were 2.9% and 22.1% and for AvicelR were 2.9% and 11.4% respectively. The significance of these could be reflected in the disintegration of tablets and storage conditions of the products. Their perticulate and packing properties show comparable values with AvicelR, indicating comparable direct compression properties with it. A non-self compressible high dose drug as exemplified by paracetamol, (500mg dose per tablet) was employed in the tablet formulation using five dry mixed concentrations from and including 10 to 30% of CAC, CMCC and Aviccl as sole excipient dry binder. Half of the excipient was dry mixed with the drug before pelletization and comminution processes while the other half was admixed extra granularly and compared in the single station tablet. Although the tablet weight varied according to the excipient content, each tablet contained 500mg of the drug. The percent weight variation were all within 2.4% with upper limits mostly within the higher excipient concentrations most probably due to higher content of exragranular fines which is amenable to higher segregative tendencies. The specific thickness in mm per mg tablet weight was generally lowest with the highest (25 and 30%) dry binder content due to higher compressibility of the tablet containing higher compressible excipient. It also followed that the hardness and the friability of the tablets were highest and lowest respectively with the highest dry binder content. The shortest disintegration time was obtained at 20% and 30% dry binder content for both CAC and CMCC while AvicelR produced exceptionally longer disintegration time at both extreme contents. CAC and CMCC at both extreme contents appear to produce better bioavailability properties than the Avicel possibly due to its lowest hardness effect observed at lowest concentration and highest hardness effect at highest binder content. The formulation was most successful at 25% excipient content with CAC and CMCC which were found superior to Aviccl , possibly consequential upon the two different plant sources.
PROPERTIES OF DIRECTLY COMPRESSED PARACETAMOL TABLETS CONTAINING ALPHA – AND MICROCRYSTALLINE – CELLULOSE DERIVED FROM MAIZE COBS