Development and in vitro evaluation of oral dissolvable films of diclofenac sodium using albizia and khaya gums as film forming polymers

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An oral dissolvable film (ODF) is a novel drug delivery system that offers a fast and accurate dosing without the need for water or any measuring device. Also, dysphagic, schizophrenic and dementia patients can use ODFs with little or no difficulty. The study sought to develop and evaluate ODFs of diclofenac sodium using albizia and khaya gums as film forming polymers. Authenticated crude albizia and khaya gums were taken through a purification process and both the crude and purified gums were evaluated for their physicochemical properties. Purified albizia and khaya gums were used to formulate seven different batches of ODFs of diclofenac sodium (~ 50 mg/4 cm2 film) using varying proportions of the gums and HPMC as a reference film forming polymer. The possible drug-excipient interaction of the formulated films was determined using FTIR spectroscopy. In vitro evaluation tests, namely: uniformity of weight, disintegration, assay, tensile strength, percentage elongation, elastic modulus and folding endurance were used to assess the physicochemical and mechanical properties of the formulated ODFs. In vitro dissolution testing was conducted in phosphate buffer pH 6.8 and the dissolution data was analysed using dissolution efficiency, difference (f1) and similarity (f2) factors, kinetic models and ANOVA-based methods. The yields of albizia and khaya gums were 39.38 % and 67.50 % respectively. The gums were free from objectionable microorganisms and had no intrinsic antimicrobial activity against nine test microorganisms. Elemental analysis showed the absence of toxic heavy chemicals like arsenic, lead, cyanide and mercury, suggesting the safety of the gums as pharmaceutical excipients. All the batches passed the assay and dissolution tests for immediate release dosage forms. All the films, except F7, showed over 80 % drug release within 14 min. Dissolution of diclofenac sodium in the film batches followed the Higuchi kinetic model with batch F1 (reference batch) having the highest dissolution efficiency. The dissolution profiles of formulations 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).
A thesis submitted to the School of Graduate Studies in partial fulfilment of the requirements for the degree of Master of Philosophy (pharmaceutics), 2015