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- Author or Editor: Ana Medeiros x
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Abstract
A number of disintegrants are available on the market. They improve tablets’ disintegration. The objective of this work is the comparison of the technological quality parameters of disintegrants using different analytical techniques. Three batches of disintegrants and their binary mixtures (water:disintegrants) were investigated. Cooling experiments were used from –30 up to 200C. The data obtained showed calorimetric differences between the samples. In the binary mixtures water showed different crystallization behaviour from the one found in the literature. According to the results DSC technique helped the quality control of different disintegrants.
Abstract
Thermal analysis is an essential analytical tool in development of new formulations as well as to study the interaction between drugs and excipients. This work aims to investigate the possible interactions between metformin and excipients as microcrystalline cellulose (Microcel MC101®), starch sodium glycolate (Explosol®), sodium croscarmellose (Explosel®), PVP K30, magnesium stearate, starch and lactose, usually employed in pharmaceutical products. TG, DSC and DTA techniques were used for the thermal characterization to track if the thermal properties of the drug substance were modified in the mixture. Disregard of the starch and lactose systems, no changes in thermal behavior of mixtures were found. Thermogravimetric studies (TG) of metformin and its binary mixtures showed different thermal behavior.
Abstract
Stability of drugs and products has a great practical interest, which is facing to strict regulation. Thermal studies, besides the determination of the thermal properties of the investigated product allow the verification of possible interactions between the drug substances and excipients. The objective of this work was to obtain solid pre-formulates of paracetamol (PC) by spray drying (SPDR), as well as to investigate their thermal behavior. Dynamic and isotherm TG, conventional DSC and DSC-photovisual coupled methods were used to characterize the conventional and pre-formulated mixtures obtained by SPDR. The results of both DSC investigations showed slight alterations in melting temperatures, which suggests incompatibilities. The TG decomposition data of the mixtures evidenced that the dry process via SPDR leads to stability enhancement of the pre-formulated mixtures.
Abstract
Compatibility studies between active drugs and excipients are substantial in the pharmaceutical technology. The objective of the present work was to develop pre-formulated mixtures of metronidazole (MT) obtained by spray drying (SPDR) and their thermoanalytical characterization. Dynamic and isothermal TG, conventional DSC and DSC coupled to a photovisual system were used. DSC experiments with both techniques confirmed the homogeneity of the conventional and pre-formulated mixtures. The TG data made possible the comparison the thermal stability of the different mixtures. Similar thermal stabilities were found of the conventional and pre-formulated mixtures, with slower particles sizes of MT.
Trypsin inhibitors have been described in peanuts and their derived industrialized foods, demonstrating diversity and thermoresistance. Given their most varied applications, these enzymatic protease inhibitors have been isolated and characterized for their potential use as bioinsecticides, herbal medicines, or medicines, but it is not simple. There are still no reports in the literature of the isolation and characterization of trypsin inhibitors in cultivar cavalo rosa (CCR) peanut, a common variety in Brazil. However, there are biological activities related to trypsin inhibitors from peanut-derived products. In this study, we isolated and characterized a novel trypsin inhibitor in CCR peanuts (Arachis hypogaea L.) under different processing conditions using a simple improved isolation. Raw and toasted peanut inhibitor was isolated by ammonium sulfate fractionation and trypsin-cyanogen bromide-activated Sepharose® 4B (CNBr-Sepharose® 4B) chromatography. The inhibitors from raw and toasted peanut were called AhTI1 and AhTI2, respectively, with potent anti-trypsin activity. Activity at different temperatures and pH was evaluated, and both samples were similarly stable under tested conditions. Minimum concentration for inhibition to occur (IC50) was 2.78 × 10−10 M and 2.39 × 10−10 M for AhTI1 and AhTI2, and inhibition constant (Ki) was 3.26 × 10−10 M and 1.54 × 10−10 M, respectively, showing non-competitive reversible kinetics. We concluded that AhTI1 and AhTI2 presented highly specific to trypsin and stable to toasting, different temperatures, and pH ranging. These are important characteristics in the process of developing bioinsecticides or biopharmaceuticals. Thus, this may be an interesting molecule, aiming at its biotechnological application, and it was obtained using a simple and easy isolation process.