Formulation of a topical haemostatic drug delivery system for minor wounds and abrasions

Hafeji, Aysha
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Haemostatic agents accelerate blood clotting and help in wound healing processes for minor wounds or abrasions. Haemostatic gauzes and bandages have been formulated to achieve quick clotting and haemostatic control in emergency combat situations. Current available haemostatic gauzes and bandages in South Africa have to be imported and are thus expensive. The purpose of this study was to prepare and evaluate a haemostatic gauze impregnated with chitosan and tannic acid as two effective and cheap haemostatic agents. The haemostatic gauze was easy to prepare and produce by means of a simple solvent casting method followed by lyophylisation. Nine different concentration combinations of tannic acid and chitosan were impregnated onto a 50mm x 50mm 8 ply gauze strip and were prepared and evaluated for various physicochemical properties, mechanical properties, dissolution into simulated body fluid, and finally tested for in vitro blood clotting ability. The different formulations were also tested to see if they maintained their sterility after 30 days of storage. The final in vitro blood clotting ability of the tannic acid and chitosan haemostatic gauze formulations were compared to Quikclot© a commercially imported haemostatic gauze. During the physicochemical analyses of the haemostatic gauze formulations, the concentration of tannic acid and chitosan in the haemostatic gauze formulations significantly affected some properties. It was found that chitosan % w/v significantly affected the viscosity, thickness, swellability and clotting ability of the haemostatic gauze formulations. However, the tannic acid % w/v had a significant effect on the swellability, dissolution and in addition to clotting ability of the haemostatic gauze formulation. As the tannic acid % w/v increased from 1% w/v to 5% w/v and the chitosan % w/v increased from 0.5% w/v to 1.5 % w/v, viscosity increased and the weight of the haemostatic gauze strips varied from 0.3884 ± 0.02 to 0.6151 ± 0.07 g. The thickness variation of the haemostatic gauze strips were found to be in between 1.023 ± 0.12 and 2.615 ± 0.29 mm. Drug content uniformity of the haemostatic gauze strips was found to be uniform throughout the various formulations (all above 94%). Swellability of the haemostatic gauze strips in simulated body fluid (SBF) varied between 654.43 ± 45.22 % and 1203.71 ± 100.2%. The tensile strength for all haemostatic gauze strips were found to be > 0.57 kg/cm2 where some of gauze strips did not break. It was also found that there was an initial quick release of tannic acid from the haemostatic gauze strips within 30 seconds and after that there was a constant release of tannic acid. Dissolution of tannic acid at 300 second has been found between 32.62 and 10.56 % μg/ml of total amount. The in vitro blood clotting ability was found to be better in our formulated haemostatic gauze than that of Quikclot© commercial gauze. Best clotting extent was found from 0.5C1TA, 1C1TA and 1C2TA formulations at 180 sec. excellent clotting rate has been found for 1C2TA formulation. However, most of the haemostatic gauze strip formulations did not found to be sterile after 30 days of storage even though tannic acid has been reported to have antimicrobial properties. In future, an effective preservative will have to be added to the formulation, or they would have to be prepared aseptically. In conclusion, the tannic acid and chitosan haemostatic gauze developed in this study presents an inexpensive and effective alternative to importing haemostatic gauzes and bandages.
A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Masters of Science in Medicine, Pharmacotherapy Johannesburg, 2019