María Ana Rosasco

A new HPLC method for azithromycin quantitation

A simple liquid chromatographic method was developed for the estimation of azithromycin raw material and in pharmaceutical forms. The sample was chromatographed on a reverse phase C18 column and eluants monitored at a wavelength of 215 nm. The method was accurate, precise and sufficiently selective. It is applicable for its quantitation, stability and dissolution tests.

Validation of an HPLC Method for the Determination of Imatinib Mesylate in Pharmaceutical Dosage

Abstract This paper describes the development and validation of a new, simple, fast, and sensitive liquid chromatographic method for the determination of imatinib mesylate. Imatinib mesylate is not listed in any pharmacopoeia, and there are few methods in the literature for its quantitation in pharmaceutical dosage forms. In this work, a C18 μBondapak® (3.9×150 mm, 5 µm) column was used as the stationary phase, and 30 mM sodium heptane sulphonic acid in 0.01 M KH2PO4 (pH 2.5):MeOH (42:58) was the mobile phase. Detection was performed on a UV detector at 237 nm. Through the evaluation of the analytical parameters, it was shown that the method is linear (r=0.9994) at concentrations ranging from 0.3 mg/mL to 0.8 mg/mL. The relative standard deviation values [RSD] for intra‐ and inter-day precision studies were 1.7 and 2.6. Recoveries ranged between 96.2 and 101.4.

HPLC Determination of Acenocoumarol and its Major Thermal Degradation Product

Abstract A High performance liquid chromatographic (HPLC) method is presented for the determination of acenocoumarol and its thermal degradation product using a reverse phase C18 column at ambient temperature with the mobile phase consisting of water, and the pH adjusted to 3.0 using phosphoric acid:acetonitrile (50∶50). Quantitation was achieved with UV detection at 280 nm based on peak area. The method was developed and validated for the determination of acenocoumarol in tablets. The proposed method was validated for selectivity, linearity, accuracy, and robustness. The method was found to be suitable for the quality control of acenocoumarol in tablets as well as the stability‐indicating studies.

HPLC Assay for Meprednisone in Tablets

Abstract A high performance liquid chromatographic (HPLC) method is presented for the determination of meprednisone in the presence of its degradation products using a reverse phase C18 column at ambient temperature with mobile phase consisting of acetonitrile:0.04 M dibasic sodium phosphate, pH adjusted to 7.0 (45:65, v/v). The flow rate was 1.3 mL/min. Quantitation was achieved with UV detection at 245 nm based on peak area. The method was developed and validated for the determination of meprednisone in tablets. The proposed method was validated for selectivity, linearity, accuracy, and robustness. The method was found to be suitable for the quality control of meprednisone in tablets as well as the stability indicating studies.

Determination of the Chemical Stability of Various Formulations of Tobramycin Eye-Drops by HPLC Method and Data Analysis by R-GUI Stability Software

Fil: Rosasco, Maria Ana. Universidad de Buenos Aires. Facultad de Farmacia y Bioquimica. Departamento de Tecnologia Farmaceutica; Argentina

Compatibility study of tobramycin and pharmaceutical excipients using differential scanning calorimetry, FTIR, DRX, and HPLC

Differential scanning calorimetry (DSC), isothermal stress testing–Fourier transform infrared spectroscopy (IST–FTIR), isothermal stress testing–high-performance liquid chromatography, and powder X-ray diffraction (PDRX) were used as screening techniques for assessing the compatibility of tobramycin with some currently employed ophthalmic excipients. In the first phase of the study, DSC was used as a tool to detect any interaction. The absolute value of the difference between the enthalpy of the pure tobramycin melting peak and that of its melting peak in the different analyzed mixtures was chosen as a parameter of the drug–excipient interaction degree. DSC results demonstrated that benzalkonium chloride, monobasic sodium phosphate, boric acid, edetate disodium, sodium metabisulfite, thimerosal, and potassium sorbate interact with tobramycin. Taking into account these results, it could be suggested that some of the changes observed in the IST–FTIR spectra of binary blends of tobramycin and some of the excipients would account for a possible interaction between the mixture component. In this study, PDRX did not provide much information, since only tobramycin–thimerosal interactions could be detected. DSC and IST–FTIR are suitable and simple methods for the detection of potential incompatibilities between active pharmaceutical ingredient (API) and excipients.

Physicochemical Characterization of Physical Mixture and Solid Dispersion of Diclofenac Potassium with Mannitol.

Diclofenac potassium is an anti-inflammatory agent classified as a class II drug as per the biopharmaceutical classification system (BCS). The poor dissolution rate of water-insoluble drugs is still a major problem confronting the pharmaceutical industry. There are several techniques to enhance the dissolution of poorly soluble drugs. Methods available include salt formation, micronization and addition of solvent or surface active agents. The objective of the present work is to improve de dissolution profile of diclofenac potassium by formation of a physical mixture and a solid dispersion with mannitol. The solid dispersion was prepared by solvent method using ethanol/water. As diclofenac potassium melts with decomposition, the compatibility study with mannitol was done with the acid form by differential scanning calorimetry (DSC). The dissolution properties and physicochemical properties of diclofenac potassium:mannitol physical mixture and solid dispersion were investigated by Powder X-ray Diffraction (PXRD), infrared spectrometry (FTIR), scanning electron microscopy (SEM) and dissolution test. This study shows that the dissolution rate of diclofenac potassium can be enhanced considerably by formulating it with mannitol, as a physical mixture or as a solid dispersion although cristallinity was maintained.

Enhancement of Dissolution Rate of Furosemide Using a Solid Dispersion with D-Glucosamine HCl

Fil: Han, Yong Ki. Universidad de Buenos Aires. Facultad de Farmacia y Bioquimica; Argentina