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.

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 (p > 0.05; f1 < 15 and f2 ≥ 50) while F7 differed markedly from F1 (p < 0.001; f1 > 15 and f2 < 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.