PHYSICOCHEMICAL EVALUATION AND TABLET FORMULATION PROPERTIES OF SHEA TREE GUM

  Objective: This study focused on evaluating the physicochemical and tablet formulation properties of shea tree (Vitellaria paradoxa) gum, using paracetamol as a model drug.Methods: Crude shea gum was purified and the physicochemical properties, namely: Moisture content, insoluble matter, solubility, swelling capacity, viscosity, hydration capacity, flow properties, and metallic ion content evaluated. The binding properties of shea gum (5-20% w/v) were investigated, using acacia gum as a standard binder. The physical properties, in vitro dissolution and dissolution efficiency (DE) of the tablets, were determined. The dissolution data were statistically evaluated using the T-test and the similarity factor (f2).Results: The physicochemical properties of the gum evaluated were found to be satisfactory and within official specifications. Atomic absorption spectrophotometric analysis of the gums showed that the crude gum had higher metallic ion content than the purified gum. The gum purification process caused a substantial reduction (17-74%) in the mineral ion content of shea gum. Granules prepared with shea gum exhibited good flow properties evidenced by their optimal Hausner ratio, angle of repose and Carr's index values. The granule flow properties, as well as the physical properties of shea gum tablets, were similar to that prepared with acacia gum. The DE of both shea gum and acacia gum tablets decreased with increase in binder concentration. Comparative studies on the tablets using DE, T-test and similarity factor (f2), showed that the binding effect of shea gum was comparable to that of acacia gum (p>0.05; f2 ≥50) at the same concentration.Conclusion: Shea tree gum has potential as a binder in pharmaceutical tablet formulations.Keywords: Vitellaria paradoxa, Viscosity, Wet granulation, Tablet binder, Dissolution efficiency, Similarity factorÂ

Development of Oral Dissolvable Films of Diclofenac Sodium for Osteoarthritis Using Albizia and Khaya Gums as Hydrophilic Film Formers

Oral dissolvable films (ODFs) of diclofenac sodium intended for osteoarthritis were prepared using Albizia and Khaya gums as hydrophilic film formers. The physicochemical properties of the gums were characterized and the gums were used to prepare diclofenac sodium ODFs (∼50 mg/4 cm 2 film) by solvent casting. The two gums showed satisfactory film forming properties. The physicomechanical properties, drug-excipient compatibility, and in vitro drug release of the films in phosphate buffer pH 6.8 were studied. Khaya gum had higher extraction yield, moisture content, insoluble matter and true density while Albizia gum showed greater swelling capacity, solubility, and minerals content. The ODFs were thin, soft, and flexible with smooth glossy surfaces and possessed satisfactory physicomechanical properties. FTIR studies showed that no interaction occurred between the drug and the gums. The ODFs disintegrated in <45 s achieved >75% drug release within 7 min with dissolution efficiencies of ∼83-96%. Drug releases from F2, F3, F4, F5, and F6 were similar to F1 ( > 0.05; 1 < 15 and 2 ≥ 50) while F7 differed markedly from F1 ( < 0.001; 1 > 15 and 2 < 50). Drug release followed the Higuchi kinetic model which is indicative of Fickian drug diffusion

Development and evaluation of natural gum-based extended release matrix tablets of two model drugs of different water solubilities by direct compression

The study was aimed at developing extended release matrix tablets of poorly water-soluble diclofenac sodium and highly water-soluble metformin hydrochloride by direct compression using cashew gum, xanthan gum and hydroxypropylmethylcellulose (HPMC) as release retardants. The suitability of light grade cashew gum as a direct compression excipient was studied using the SeDeM Diagram Expert System. Thirteen tablet formulations of diclofenac sodium (∼100 mg) and metformin hydrochloride (∼200 mg) were prepared with varying amounts of cashew gum, xanthan gum and HPMC by direct compression. The flow properties of blended powders and the uniformity of weight, crushing strength, friability, swelling index and drug content of compressed tablets were determined. In vitro drug release studies of the matrix tablets were conducted in phosphate buffer (diclofenac: pH 7.4; metformin: pH 6.8) and the kinetics of drug release was determined by fitting the release data to five kinetic models. Cashew gum was found to be suitable for direct compression, having a good compressibility index (ICG) value of 5.173. The diclofenac and metformin matrix tablets produced generally possessed fairly good physical properties. Tablet swelling and drug release in aqueous medium were dependent on the type and amount of release retarding polymer and the solubility of drug used. Extended release of diclofenac (∼24 h) and metformin (∼8–12 h) from the matrix tablets in aqueous medium was achieved using various blends of the polymers. Drug release from diclofenac tablets fitted zero order, first order or Higuchi model while release from metformin tablets followed Higuchi or Hixson-Crowell model. The mechanism of release of the two drugs was mostly through Fickian diffusion and anomalous non-Fickian diffusion. The study has demonstrated the potential of blended hydrophilic polymers in the design and optimization of extended release matrix tablets for soluble and poorly soluble drugs by direct compression. Keywords: Cashew gum, Xanthan gum, HPMC, Direct compression, SeDeM Diagram Expert System, Diclofenac sodium, Metformin hydrochlorid

Preliminary health risk assessment of two exudate gums as pharmaceutical excipients

Some exudate gums such as acacia and tragacanth gums have been certified to be used in pharmacy as excipients. In this study exudate gums, obtained from two local trees in Ghana: Cussonia arborea and Cordia mellinii, were assessed for their safety for use as pharmaceutical excipients. The crude gums were purified using water and 96% ethanol and digested by di-acid procedure using 65% HNO3 and 37% HCl (2:3) at 95 °C for elemental analysis. Quantification of Ca, Fe, Mg, Cu, Zn, Mn, Ni, Hg, Cd, Pb and As ions was done using AAS 400; Na and K using the single channel flame photometer; and P using Spectronic 20 spectrophotometer. Microbial quality of the purified gums was also determined by the British Pharmacopoeia method. Toxicity of the purified gums was evaluated using acute and sub chronic murine toxicity models. Quantities of elemental ions detected in both purified gums were not significantly high to affect the utilization of these gums as pharmaceutical excipients even in large dose and high dosing frequency drugs. Total aerobic viable counts of the gums were within the acceptable Pharmacopoeial specification and no harmful microorganisms were detected. Acute and sub-chronic toxicity tests of the gums showed that they are safe for use even in long term dosage regimen medications. Thus, when these gums are included in even long term use medicines as excipients, may not cause any harm to the patient. The gums are therefore safe and qualified for use as pharmaceutical excipients when purified

Physicochemical and Microbiological Characteristics of Stem Bark Exudate Gum of Cordia millenii Tree in Conventional Release Tablets

The development of a raw material into an acceptable pharmaceutical excipient involves evaluation of the physicochemical and formulation properties of the potential raw material. Results from these evaluations may serve as a guide to subsequent use of the substance. The objective of the study was to evaluate the physicochemical and microbiological properties of the stem bark gum of Cordia millenii tree in conventional release paracetamol tablets. From the physicochemical evaluations, the gum was slightly acidic and soluble in all the aqueous-based solvents, except 0.1 N HCl in which it was sparingly soluble. All the absorptive properties of the gum indicated tablet disintegrating potential for tablet formulation. The total ash of the gum was higher than that of the international standard gum arabic. Micromeritic properties of the gum indicated the need for a flow aid to improve its flowability. There were no harmful microorganisms detected in the gum. Aerobic organisms and moulds and yeast were detected within permissible limits. Tablets formulated using six different concentrations of gum dispersions as a binder were generally soft and failed the USP T80 standard of dissolution, indicating poor binding and drug releasing properties. Quality control properties of three different batches of tablets containing varying concentrations of the dry gum as a disintegrating agent were comparable to tablets containing equal concentrations of corn starch. The in vitro drug releases were similar at all-time points of drug evaluation. The gum can therefore be considered as a good disintegrant in the formulation of conventional release tablets