Author: Elena Gabriela Oltean Affiliation: Romvac Company SA
The organic or inorganic impurities in the veterinary medicinal product can derive from starting materials, manufacturing process, incomplete purification, inappropriate storage. The acceptable levels of impurities in pharmaceuticals are estimated by comparison with standard solutions, according to the appropriate monographs. Forced degradation studies determine the stability of the method of dosage for the active compounds and for the entire finished product under excessive accelerated degradation conditions. They also provide information on degradation pathways and selectivity of analytical methods applied. The information provided by the degradation studies on the active compound and finished pharmaceutical product should demonstrate the specificity of the analytical method regarding impurities. Forced degradation studies should demonstrate that the impurities and degradation products generated do not interfere with the active compound. The current forced degradation methods consist of acid hydrolysis, basic hydrolysis, oxidation, exposure of the medicinal product to temperature and light. HPLC methods are an integral analytical instrument for the analysis of the medicinal product. The HPLC method should be able to separate, detect and quantify various specific degradation products that can appear after manufacture or storage of the medicinal product, as well as new elements appearing after synthesis. FDA and ICH guidelines recommend the enclosure of the results, including the chromatograms specific to the forced degradation-subjected medicinal product, in the documentation for marketing authorization. Using HPLC methods in forced degradation studies on medicinal products provides relevant information on the method of determination for the formulation of the medicinal product, synthesis product, packaging methods and storage.
Authors: Maria Neagu, Cristina I. Marinescu, Roxana M. Covaci, Catalina S. Macovei Affiliation: SC Delos Impex ’96 SRL, Bucharest, RO.
Because, triclabendazole is an active pharmaceutical ingredient without compendial monography (European Pharmacopoeia, United Stated Pharmacopoeia) in SC Delos Impex ’96 SRL, the API identification, assay, related substances, and, preservatives, assay and identification is efectuated used the method presented below. Presented original method permit, all these determination in a relative short time (the chromatogram time recorded is 25 min.).
Autori: Carmen Lidia Chițescu1, Anca Nicolau2
1 S.C. Pasteur, Filiala Filipesti, 2 Universitatea Dunarea de Jos, Galati
Sulfadimethoxine, sulfamethoxazole, sulfaquinoxaline and sulfadiazine are the most common used sulfonamides in veterinary practice. The recommended withdrawal periods if not observed before slaughtering of the medicated animals, the products may obtain from such animals may be contaminated with residue. The interest in having reliable methods able to detect low amounts of sulfonamides in food is very actual. In this study, a multiresidue analysis was performed to simultaneously determine those four sulfonamides in chicken muscle tissue by the Waters LC. Criteria of validation: specificity, accuracy, precision, limit of detection, limit of quantification, and linearity, according to the European Commission Decision 2002/657/EC, show that the method can detect different kinds of sulfonamides within one run, without mass spectrometry analyses, or Fluor metric derivatization of analyts. The method is accurate, simple, economical in both time and cost, capable of detecting sulfonamides residues below the maximum residue limits (MRL) and easy to perform to routine samples, in normal condition of laboratory. The sulfonamides were extracted with acetonitrile and acetone and dichloromethane. N-hexane was added for defeating the sample. Separation was carried out on a Zorbax SB- C18 analytical column, using as mobile phase a mixture of 75:25 = di-natrium-hydrogenphosphat solution 6 g/1000 ml (pH = 8.5) : methanol. The detection wavelength was set at: 254 nm Calibration graphs were linear with very good correlation coefficients in the concentration range from 0.320 to 1.5ìg /mL. The limits of quantification (LOQ) for the sulfonamides were in the range of 6.6–0.34 ìg /kg. The recovery for spiked chicken muscle with 50–150 ìg/kg ranged more than 70%. The relative standard deviation (Reds) of the sulfonamides for six measurements at 50 go/kg, 100 ìg /kg and 150 ìg /kg was less then 15%. The applicability of the method to the analysis of chicken muscle tissue was demonstrated.
Authors: Dan Dragos and Zoltan Szabadai Affiliation: Universitatea de Medicină si Farmacie „Victor Babes” Timisoara, Facultatea de Farmacie
The main inconvenience of analytical determination of Tinidazole in pharmaceutical formulations consists in the presence of ingredients, frequently with unknown identity. In order to overcome the complications of methods based on selective separations, a spectrophotometrical method for Tinidazole assay was performed and tested. By appropriate derivatization of the analythe, a photometrically estimable Schiff base is obtained, with absorption in the visible region where the interference of ingredients is negligible. The linearity of analytic signal was checked out in methanol solution in the 2-14 mg/l concentration domain. The method exhibit a good reproducibility: in a 8-fold repetition the main standard deviation is 0.38 % of the average of individual values.