Separation, identification, and quantitation of anthralin and its decomposition products.

Anthralin and its decomposition products were separated by both column chromatographic and TLC techniques. Two decomposition products were characterized by TLC, melting-point data, and UV and IR spectroscopy. Pure anthralin and its decomposition products also were determined quantitatively.

Multiple compression and plasto-elastic behaviour of paracetamol and microcrystalline cellulose mixtures.

Radial tensile strength, friability, ER/PC (elastic recovery/plastic compression) ratio and energy ratio analyses were evaluated for various mixtures of paracetamol and microcrystalline cellulose (Avicel). A good correlation occurred between the energy ratio and the other variables. Linear relationships were found between log tensile strength and percentage energy ratio and also between radial tensile strength and stress relaxation energy. Capping occurred when the percentage energy ratio was greater than 15% and the ER/PC ratio greater than 1.5. To produce tablets with acceptable tensile strength and friability, the percentage energy ratio for Avicel/paracetamol should be greater than 10%. The optimal mixture of the two powders, as far as the tensile strength, friability and absence of capping were concerned, was found to be 50% w/w Avicel, 50% w/w paracetamol.

Physical properties and dissolution profiles of acetaminophen and acetylsalicyclic acid tablets made from sucrose-based vehicles.

Di-pae, Sugartab and Nu-Tab were used as direct compressible vehicles for acetaminophen and acetylsalicylic acid tablets. Direct compressible grades on lactose and Avicel were used as vehicles for comparison. Three different packing fractions were employed for tabletting acetaminophen and acetylsalicylic acid. The physical properties and dissolution characteristics of the prepared tablets depend on their packing fraction i.e. the mechanical strength, and disintegration and dissolution time are lowest at the lowest packing fraction and vice versa. It was found that the time required for maximum dissolution rate (t90) of drug was usually longer than the disintegration times of tablets and also t90 of acetylsalicylic acid was found to be faster than that of acetaminophen with all tested vehicles.

The influence of binder type and concentration on the physical characteristics of calcium carbonate granules and their corresponding tablets.

Most studies involving binders are concerned with the properties of the final product. Very little has been done at comparing the mechanical properties of the granules, the force required to crush the tablets and the compression behavior. The aim of this investigation was to study the effect of different concentrations of five binders namely gelatin, PVP, methylcellulose, syrup and Eudragit E on the mechanical and physical properties of calcium carbonate granules and correlating that with the characteristics of the corresponding tablets. A template method was used for the preparation of calcium carbonate granules. The wet granules were dried for 34 h in air oven at 60 degrees C and were conditioned for a minimum of 2 h at 50% relative humidity before testing or tableting as this corresponds approximately to ambient conditions. The granules, were separated into different size fractions using the sieve analysis method, and were then measured for crushing strength (K), friability (%), flow ability, bulk volume and tap density. The granules possessing the best mechanical and physical characteristics were used for tableting. The compact obtained were also evaluated for both mechanical and physical properties. It was found that increasing the binder concentration was followed by an increase in the mean particle diameter, harder granules (-kt = ln Wa divided by W + Wb . db divided by W . da) and reduction in tap density. Except for those prepared with 2% methylcellulose and 30% syrup, all tablets prepared from granules with optimum properties are found to satisfy U.S.P. requirements of weight, thickness, disintegration time and mechanical properties.

Effect of guar gum on the dissolution rate of ephedrine hydrochloride and sulphadimidine tablets.

The effect of guar gum as a binder was studied in comparison with other commonly used binders namely: gun acacia, Carbopol 934, sodium carboxymethyl cellulose and Explotab on the disintegration time and the dissolution rate of tablets containing ephedrine hydrochloride and sulphadimidine. The results revealed that the solubility of the drug as well as the concentration and the type of binder affect both the disintegration time and the dissolution rate of the tablet.