[Chemical composition of Mineral Trioxide Aggregates [MTA]: a review of literatures]

In 1993, Mineral Trioxide Aggregates [MTA], a grey-colored material was introduced to dentistry. A similar product in white-color was also produced later. The aim of this study was to review the literature in order to compare the chemical composition of these two different types of MTA. Over 600 articles have been published about the properties of MTA, 33 of which were about chemical and 28 were on its physical properties. In addition, about 80 articles have been published on similarities and differences between MTA and Portland Cements [PC]. This article reviews the history of MTA's manufacturing, its introduction to market, its patent, its commercial brands, and its similarities with PC. We also reviewed size of powder particle, setting form, and also hydration reaction of MTA. Mainly consisting of CaO and SiO2, MTAs and PC have similar compositions. MTA also contains Bi2O3 as an opacifier. The main difference in chemical composition of white MTA and PC with grey MTA is that the latter contains less amount of some minor elements specifically FeO. White MTA has finer particles and crystals compared to the grey one. No phosphate does exist in MTA composition, but during the hydration, this material is able to release calcium and hydroxyl ions which, in reaction to exogenous phosphate, results in hydroxyapatite formation. Both MTA and PC are hydrophilic cements. Regarding the biocompatibility of these materials, MTA is considered suitable for clinical applications; while no permission exists for clinical use of PC

Stability indicating methods for the quantitative determination of pseudoephedrine HCl and guaifenesin and dextromethorphan HBR in a cough syrup using HPLC

The determination of three active ingredients in a multicomponent pharmaceutical product by HPLC using two columns is reported. Guaifenesin and dextromethorphan HBr were separated and quantitated simultaneously in a cough syrup using an isocratic reversed phase system. The mobile phase was 45% [v/v] aqueous methanol with ammonium formate as buffer [PH 4.3]. the range of concentrations used in the determination of guaifenesin and dextromethorphan HBr were 202-363 mg/100ml and 30-54 mg/100 ml, respectively. A separate method was developed for the determination of pseudoephedrine HCI using a normal phase system. The mobile phase was 80% [v/v] aqueous ethanol with ammonium acetate as buffer [pH 7.3]. the range of concentrations used in the determination of pseudoephedrine HC1 was 60-108 mg/100 ml. Both methods proved to be repeatable, reproducible and stability indicating