Formulation of Non-effervescent Floating Dosage Form of Metronidazole using Sintering and Sublimation Technique

The aim of this study was to formulate a novel non-effervescent floating dosage form of metronidazole using the sublimation and sintering technique. Granules were formulated using the wet granulation technique. Ammonium bicarbonate (30% w/w) was incorporated as the sublimating agent. The granules were characterized for micromeritic properties. Thereafter, the granules were compressed using a single punch tableting machine and the physicotechnical properties were evaluated. The metronidazole tablet was then sintered at 70oC for 12 h. All granules were free flowing and compressible. The metronidazole tablets had no floating lag time showing that tablets floated instantaneously. FTIR and DSC studies showed that metronidazole and the excipients used in the formulation were compatible. Azadirachta indica gum was used in the formulation of non-effervescent floating dosage form of metronidazole using sublimation and sintering technique which is beneficial in sustained release formulations. Dhaka Univ. J. Pharm. Sci. 20(1): 11-17, 2021 (June)

Assessment of the naphthalene sublimation technique for determination of convective heat transfer in fundamental and industrial applications

The naphthalene sublimation technique is an experimental method for indirectly determining convective heat transfer. The technique is here assessed for two different configurations: the local heat transfer distribution for a circular air jet impinging normal to a flat surface, and the heat transfer occurring in the stator core of an electric generator model. The turbulent impinging jet is fully developed. Two Reynolds numbers based on the nozzle exit condition, 15000 and 23000, and two nozzle diameter distances from the jet exit to the surface, 6 and 8, are considered. For the generator turbulent internal flow with Reynolds number of 4100 is considered, based on the hydraulic diameter of stator ventilation ducts. Modern surface scanning methods and imprints of the naphthalene specimens were used for measuring the naphthalene sublimation rate. The impinging jet results are compared with experimental data found in the literature. Results from the generator model and numerical simulations are compared. For the impinging jet, the results show agreement with the already published experimental data sets. For the generator model, heat transfer results from experiments differ by around 13% compared to numerical results if a scanning of the surface is used for measuring the naphthalene sublimation and around 5% if weights are used for measuring the sublimation rate. Therefore, the results depend on the way the sublimation rate is quantified. From this study, it is possible to affirm that with advanced scanning procedures, the heat transfer can be resolved with very small naphthalene sublimation in cases of both fundamental and complex industrial applications such as electric generators.

FORMULATION DEVELOPMENT AND EVALUATION OF ORALLY DISINTEGRATING TABLET OF CHLORPHENERAMINE MALEATE BY SUBLIMATION TECHNIQUE

Objective: Chlorpheneramine maleate is a first-generation antihistamine drug used in the treatment of allergic conditions like rhinitis, urticaria, and cough cold, etc. In present work, the challenge has been made to develop an orally disintegrating tablet of chlorpheneramine maleate with an increase in bioavailability and patient compliance. Methods: The sublimation technique was used to prepare orally disintegrating tablets. Porous tablet prepared after sublimation of camphor at 60 °C in a hot air oven for 60 min. In the research work, 32full factorial design used to find out the effect of two variables like the amount of Crospovidone and Croscarmellose sodium. Results: All prepared formulations were analyzed for various parameters. DSC of pure drug and optimized formulation A (9) showed purity of sample and compatibility of all ingredients with each other. In FTIR study of pure drug and optimized formulation A (9) no major shifts were seen. An optimized formulation (A9) was found to have good hardness (3.2 kg/cm2), friability (<1%), disintegration time (26 s), % drug release (99.77 %) within 6 min. Conclusion: The result obtained showed that orally disintegrating tablet of chlorpheneramine maleate enhances dissolution rate, improves bioavailability which will improve patient compliance.