The effect of formulation additives on the properties of films prepared using Terminalia randii Baker F Gum

Background: Natural polymers are becoming useful excipients in pharmaceutical formulations due to their non-toxic and biodegradable properties. One of their common uses is in the manufacture of polymeric films.Objective: This present work is to evaluate the effect of plasticizer type and polymer type on the properties of Terminalia films.Method: Films were prepared by solvent casting method using Terminalia, xanthan gums and hydroxylpropy lmethylcellulose (HPMC). Terminlia was also combined with xanthan, HPMC at different ratios using propylene glycol and glycerol as plaasticizers. The films were characterized using adherence, folding endurance and mechanical properties were determined using tensile strength and percent elongation. Disintegration was carried out in a disintegration apparatus using distilled water, 0.1M HCl (pH 1.2) and phosphate buffer pH 6.8.Result: Films prepared with Terminalia and those prepared by combining Terminalia and xanthan gums showed adherence. Films plasticized with glycerol had higher folding endurance and tensile strength. When HPMC was combined with Terminalia, the disintegration of the films produced was significantly (p<0.05) reduced at pH 6.8Conclusion: Glycerol plasticizer produced films with optimal properties, while combination of Terminalia gum and HPMC, produced films with optimal properties. Therefore, plasticizer and polymer must be carefully chosen for film formulations

Matrix Release from Tablets Prepared with Aqueous Dispersion of an Acrylate Methacrylate (a Water -Insoluble) Copolymer as Binder

Purpose: To investigate the binder effect of aqueous dispersions of acrylate methacrylates (AMA) copolymer with a view to obtaining matrix (non-disintegrating) tablets with a retard release property. Methods: Aqueous dispersions of AMA (1-15w/v) were formed by a coacervation procedure using ethanol (10 ml) as solvent and water (90 ml) as non-solvent for the copolymer. The aqueous dispersions were used to wet-mass the drug (paracetamol) powder. Resulting granules were compressed to 500 mg tablets using a single punch machine. The tablets were subjected to hardness; friability; disintegration and dissolution tests. Results: The granules formed hard tablets (tensile strength 1 - 2.0 MNm-2) with low friability decreasing from 2 to 1as the AMA binder concentration increased from 0.75 to 11.25w/w. The tablets failed to disintegrate in 3 hr. Drug release generally followed the Higuchi square root of time kinetic (R2 = 0.95). The AMA binder markedly retarded drug release as reflected by the sharp decrease in the dissolution rate constant from 30 min-2 (AMA; 0.75w/w) to 9 min-2 (AMA; 11.25w/w). Conclusion: The AMA dispersion is an effective binder; producing matrix tablets with a retard release property controlled by the binder content in the tablets

Relationship between Slugging Pressure and Brittle Fracture Tendency - A Case Study for Aspirin Tablets

OBJECTIVE - Slugging is a pre-compression technique for the dry granulation of hydrolysable drugs (e.g. aspirin). The study was carried out to relate the slugging load to the hardness of the granules and the brittle fracture tendency of the final (recompressed) tablets. METHOD - Varying compression load were applied to aspirin powder to form slugs; which were subsequently broken down to form granules. These were recompressed to give the final tablets. The hardness of the slugs was determined and taken as measure of the hardness of the resulting granules. The following tableting parameters were measured for the final tablets - tensile strength (T); packing fraction (P[f]) and the brittle fracture index (BFI). RESULTS - A high slugging load was associated with the formation of hard slugs and hence hard granules. Upon recompression the hardest granules formed the hardest tablets (T = 3.29MN m**-2) while the softest granules formed the softest tablets (T=1.09MN m**-2). In turn; the hardest tablets displayed the highest brittle fracture tendency (BFI = 0.59) compared with the softest tablets (BFI= 0.21). A positive linear correlation existed between tablet hardness (T) and BFI values (r = 0.98). CONCLUSION - The study showed that excessive slugging load produces hard aspirin granules which in turn yields hard but friable tablets

Effects of Interacting Variables on the Tensile Strength and the Release Properties of Paracetamol Tablets

"PURPOSE: The individual and interaction effects of nature of binder (N); concentration of binder (C) and the relative density (D) on the tensile strength and release properties of paracetamol tablets have been studied using a 23 factorial experimental design. METHODOLOGY: Khaya gum; which represented the ""low"" level; and polyvinylpyrrolidone (PVP); which represented the ""high"" level; was used as binding agent at concentrations of 0.5 percent and 4 percentw/w in a paracetamol tablet formulation. The tensile strength; which is a measure of the bond strength of tablets; and the release properties of the tablets-measured by the disintegration and the dissolution times; were used as assessment parameters. RESULTS: Changing the concentration of binder and the relative density of the tablets from ""low"" to ""high"" led to an increase in the tensile strength and the disintegration and dissolution times of the tablets. The ranking of the individual coefficient values for the formulations was D less than N less than C for T and C > N less than D for the disintegration and dissolution parameters while the ranking for the interaction effects was N -D > N -C less than C - D for T and t[50]; N -C > N - D C -D for DT and C -D less than N -C > N -D for t[90]. CONCLUSION: The results suggest that khaya gum could be useful as an alternative binding agent to produce tablets with particular tensile strength and drug release profiles and there was considerable interaction between the variables employed on the tablet properties."