The pharmaceutical cocrystals are nowadays studied due to the fact that several properties, such as solubility, stability, dissolution rate and bioavailability, can be modulated. In this work, a cocrystal containing carbamazepine (CBZ) and succinic acid (SA) were prepared by the cogrinding method of the active substances, following the subjection of the physical mixture to microwave irradiation. The formation and stability of CBZ-SA cocrystal were explored using thermoanalytical methods (TG/ DTG/HF), Fourier transform infrared spectroscopy and PXRD pattern diffraction. The preparation of the cocrystal was realized by slow evaporation of solvent (ethanol) from the mixture which contained the active substances in molar ratio CBZ:SA = 2:1.
BackgroundThe compatibility study of active substances with excipients finds an important role in the domain of pharmaceutical research, being known the fact that final formulation is the one administered to the patient. In order to evaluate the compatibility between active substance and excipients, different analytical techniques can be used, based on their accuracy, reproducibility and fastness.ResultsCompatibility study of two well-known active substances, procaine and benzocaine, with four commonly used excipients, was carried out employing thermal analysis (TG/DTG/HF) and Fourier Transform Infrared Spectroscopy (UATR-FT-IR). The selected excipients were microcrystalline cellulose, lactose monohydrate, magnesium stearate and talc. Equal proportion of active substance and excipients (w/w) was utilized in the interaction study. The absolute value of the difference between the melting point peak of active substances and the one corresponding for the active substances in the analysed mixture, as well the absolute value of the difference between the enthalpy of the pure active ingredient melting peak and that of its melting peak in the different analysed mixtures were chosen as indexes of the drug-excipient interaction degree. All the results obtained through thermal analysis were also sustained by FT-IR spectroscopy.ConclusionsThe corroboration of data obtained by thermal analysis with the ones from FT-IR spectroscopy indicated that no interaction occurs between procaine and benzocaine, with microcrystalline cellulose and talc, as well for the benzocaine-lactose mixture. Interactions were confirmed between procaine and benzocaine respectively and magnesium stearate, and for procaine and lactose.
The importance of developing new pharmaceutical final formulations is nowadays well known. In this paper, we present the study of compatibility between bioactive antihyperlipidemic agent simvastatin and eight currently used pharmaceutical excipients for developing solid dosage forms, namely starch, microcrystalline cellulose, lactose monohydrate, polyvinylpyrrolidone, colloidal silica, talc, magnesium citrate and sorbitol. The compatibility investigations were carried out under ambient temperature by FTIR spectroscopy studies and PXRD patterns and then completed by the use of thermal analysis (TG/DTG/HF) data to study the influence of temperature over stability of binary mixtures.
In this paper, the kinetic behavior of decomposition of a well-known bioactive substance used for treating dyslipidemia and the prevention of cardiovascular disease drug from statin class, namely pravastatin, was described. The kinetic study was performed on the main decomposition process which occurs at nearly 200°C, for both pure active substance and a generic commercial formulation that contain 40 mg pravastatin per tablet, using Kissinger, Friedman, Kissinger-Akahira-Sunose, FlynnWall-Ozawa and NPK methods. The stability of pravastatin as pure active substance and as tablet was compared by means of kinetic data, and the results suggested that in the solid pharmaceutical formulation, PRV has an increased stability compared to pure active substance.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.