Lubricating effects of cocoa butter and coconut oil in conventional paracetamol tablets

Background: Due to chemical instability of some Active Pharmaceutical Ingredients often caused by magnesium stearate and its impurities, it is expedient to research into some other materials especially of natural origin, which would probably exhibit better lubricating activity, chemically inactive, less bioactive and less prohibitive.Objective: This work is designed to examine the lubricating properties of cocoa butter and coconut oil as alternative lubricants in comparison with conventional lubricant - magnesium stearate at different concentrations in paracetamol tablets. Materials and Methods: Cocoa butter was extracted from the seeds of Theobroma cacao and coconut oil from the meat of matured coconuts harvested from the coconuts palm (Cocos nucifera).Physicochemical evaluation was carried out on the extracted oils. Thirteen different formulations were prepared using different lubricants; magnesium stearate, cocoa butter and coconut oil at 0 ­ 4 %w/w concentrations. The prepared granules were evaluated for various pre-compression characteristics (bulk density, tapped density, angle of repose, Hausner's quotient and Carr's index) and post-compression characteristics (weight variation, friability, hardness, disintegration and dissolution times).Results: Most of the values obtained from the evaluation of pre- and post- compression characteristics correlate with the pharmacopoeial limits. The values of disintegration time were observed to increase as the lubricant concentration increased but no direct relationship with dissolution time. Tablet hardness values decreased while friability increased as the lubricant concentration increased for all the batches. From the study, cocoa butter and coconut oil at 2 ­ 4 % exhibited effective lubricating effect in the formulation of paracetamol tablet with respect to their values of weight variation, friability, hardness, disintegration and dissolution times.Conclusion: Cocoa butter and coconut oil could be employed as good alternative lubricants to the conventional ones in pharmaceutical tablet formulation

Surface activity as basis for pharmaceutical applications of hydrocolloids: A review.

Hydrocolloids are polymeric substances with mild to moderate surface activity. They are widely used as excipients in drug delivery systems where they serve various purposes such as suspending, emulsifying, wetting, foaming, solubilizing, stabilizing and bioadhesive agents as well as permeation enhancers. The surface activity and pharmaceutical applications of some hydrocolloids were reviewed in this study. The review showed that most natural hydrocolloids are characterized by higher critical micelle concentrations (CMC) compared to semisynthetic and synthetic ones. Cashew and khaya gums (exudates gums) with hydrophile – lipophile balance (HLB) values in the range of 15 - 18 possess solubilizing property. Dispersions of afzelia and prosopis gums (seed gums) have higher viscosity compared to acacia gum and may produce more stable disperse systems. Semisynthetic and synthetic hydrocolloids like sodium carboxyl methylcellulose and polyvinylpyrrolidone are characterized by low CMC and exhibit very high surface elasticity at concentrations above CMC thus exhibiting high bioadhesive strength. Therefore, surface activity is the basis for most pharmaceutical applications of hydrocolloids and the application of individual hydrocolloid depends on its adsorption power, CMC, HLB value and bioadhesive strength.

Influence of Some Starch Mucilages on Compression Behaviour and Quality Parameters of Paracetamol Tablets.

Aims: To evaluate the effect of mucilages of natural and pregelatinized forms of trifoliate yams, rice and official corn starch binders on a paracetamol tablet formulation. Methodology: Natural starches from two trifoliate yam varieties, and rice were isolated and pregelatinized. Both starch forms were then incorporated into a paracetamol tablet formulation as binders. The influence of the binders on compaction of granules and quality of tablets was assessed. Particle, bulk and tapped densities were measured for all the batches of the prepared paracetamol granules. The Heckel and Kawakita plots from which mean yield pressure, Py and another pressure term Pk, which indicates the pressure required to reduce the volume of the granule bed by 50%, were derived respectively. Both were employed to assess the compaction behaviour of the granules. Quality of the compressed tablets was studied using tensile strength, friability, disintegration time and dissolution properties as evaluation parameters. Results: Pregelatinized starch mucilages generally show lower values of both Py and Pk than natural starch mucilages. Increased concentration of starch mucilage binder also yielded lower values of both Py and Pk. Tablets containing natural starches exhibited higher Tensile strength and lower friability than those formulated with pregelatinized starch binders. Generally, Disintegration time (Dt) and the time taken for 80 % paracetamol to be released (t80) were higher for formulations containing natural starch binders than those containing pregelatinized binders The drug dissolution rate constants k1 and k2, were higher for formulations containing pregelatinized binders. Conclusion: The results obtained are suggestive of the fact that the use of mucilage of pregelatinized starch (rather than natural starch), as well as increase in concentration of the material, would yield formulations with faster onset of plastic deformation as well as higher total plastic deformation. The experimental starches compared well with the standard official corn starch and may thus be developed as substitutes in some tablet formulations.

Disintegrant activities of natural and pregelatinized trifoliate yams, rice and corn starches in paracetamol tablets.

Natural and pregelatinized starches from white and yellow trifoliate yams and rice were comparatively studied with official corn starch, in a paracetamol tablet formulation to assess their relative effectiveness as disintegrants. Disintegration time (Dt) and the (crushing strength/friability)/disintegration time ratio (Cs/Fr)/Dt were employed as assessment parameters. Generally, the rankings of (Cs/Fr)/Dt for the natural and pregelatinized starch disintegrants were white T. yam > corn > yellow T. yam > rice; and white T. yam > yellow T. yam > corn > rice, respectively. Pregelatinized starches produced better combined disintegrant properties of (Cs/Fr)/Dt than natural starches. Tablets formulated with official corn starch disintegrant exhibited the lowest disintegration time values, but generally all the tablets containing the experimental starches also passed the official disintegration time test, and can therefore be used as alternative disintegrants in tablets.