Applied chiral phase liquid chromatography in enantiomeric separation of cardiovascular drugs

A maioria dos agentes terapêuticos, freqüentemente prescritos, é formulada e comercializada sob a forma racêmica, embora, para alguns deles, já tenha sido demonstrado que os efeitos farmacológicos e/ou tóxicos estejam relacionados apenas a um dos enantiômeros. Além disso, é conhecido o fato de que os enantiômeros podem apresentar perfis farmacocinéticos e farmacodinâmicos diferentes. Neste trabalho foram selecionados compostos que fazem parte de um importante grupo de fármacos muito empregados na terapêutica. São fármacos freqüentemente prescritos em doenças cardiovasculares. As separações enantioméricas diretas do atenolol, betaxolol, metoprolol e nadolol foram obtidas utilizando-se fase estacionária quiral do tipo carbamato de celulose tris-3,5-dimetilfenil, Chiralcel OD®, (250 x 4.6 mm, 10 µm). Os enantiômeros do pindolol foram separados com fase estacionária quiral derivada de dinitrobenzoil (DNB), a-Burke 2®, (250 x 4.6 mm, 10 µm). Os fármacos foram cromatografados à temperatura ambiente, com volume de injeção de 20 µL. A detecção foi efetuada em 276 nm exceto para o pindolol, que foi detectado em 220 nm. Os métodos propostos neste trabalho empregando CLAE-FEQs oferecem vantagens sobre as técnicas clássicas de separação de enantiômeros e podem ser empregados na análise quantitativa dos enantiômeros em preparações farmacêuticas e amostras biológicas.The majority of frequently prescribed therapeutic agents are formulated and commercialized in the racemic form, even though, for some of them, it has already been demonstrated that the pharmacological and/or toxicological effects are associated only with one of the enantiomers. Moreover, it is well known that these antipodes can present different pharmacokinetic and pharmacodynamic profiles. In this work we selected drugs that belong to an important group of pharmaceuticals, frequently prescribed in the treatment of cardiovascular disorders. The direct enantiomeric separations of atenolol, betaxolol, metoprolol and nadolol were obtained using the chiral stationary phase cellulose tris-3,5-dimethylphenyl-carbamate, Chiralcel OD® (250 x 4,6 mm, 10 µm). The enantiomers of pindolol were separated with the chiral stationary phase derived from dinitro-benzoyl (DNB) (S, S) alpha-Burke 2® (250x4.6 mm, 10 µm). The drugs were chromatographed at room temperature, with injection volumes of 20 µL. The detention was made at 276 nm except for pindolol, which was detected at 220 nm. The proposed methods in this work using HPLC-CSP offer advantages over contemporaneous techniques of enantiomeric separation, being rapid and efficient, and can be used in the simultaneous quantitative analysis of referred enantiomers in pharmaceutical preparations and biological samples

Statistical methods used for comparison of analytical methods

A estatística pode ser considerada como a ciência que estuda a organização, a descrição, a análise e a interpretação dos dados experimentais. A estatística é aplicável a qualquer ramo do conhecimento onde se manipulem dados experimentais. Assim, a Física, a Química, a Engenharia, a Economia, a Medicina, a Biologia, as Ciências Sociais, as Ciências Administrativas, etc, tendem cada vez mais a servir-se dos métodos estatísticos como ferramentas de trabalho. Profissionais com diferentes tipos de formação são preparados para efetuar determinações físicas, químicas e físico-químicas em diferentes materiais e amostras. Esta tarefa envolve, entre outros aspectos, a determinação quantitativa de elementos e/ou substâncias presentes em matrizes das mais diversas. Por outro lado, os laboratórios de medições são responsáveis pela garantia da qualidade de seus resultados analíticos. Desta maneira, os integrantes dos laboratórios necessitam estabelecer critérios para a avaliação dos resultados laboratoriais obtidos. O objetivo deste trabalho foi o de reunir, em língua portuguesa, conhecimentos básicos sobre o uso da estatística na comparação de métodos analíticos utilizados rotineiramente em laboratórios de pesquisa e análise de medicamentos e cosméticos.Statistics can be considered as the science that studies the organization, description, analysis and the interpretation of experimental data. Statistics is widely used in many areas of scientific investigation. Thus, Physics, Chemistry, Engineering, Economy, Medicine, Biology, Social Sciences, Administrative Sciences etc, tend to use more and more statistical methods as working tools. Professionals of different areas are able to make physical and chemical determinations, in different materiais and samples leading quantitative determination of elements and/or substances. On the other hand, the analytical laboratories are responsible for the quality of the results, so the analysts need to establish criteria for the evaluation of the data obtained in the analysis. The aim of this work was to present, in Portuguese, the basic statistical elements used to compare the results obtained in quantitative determination of the same samples using different methods in the analysis of pharmaceutical preprarations and cosmetics

Derivative spectrophotometric method for determination of acyclovir in polymeric nanoparticles

A derivative spectrophotometric method was validated for quantification of acyclovir in poly (n-butylcyanoacrylate) (PBCA) nanoparticles. Specificity, linearity, precision, accuracy, recovery, detection (LOD) and quantification (LOQ) limits were established for method validation. First-derivative at 295.2 nm eliminated interferences from nanoparticle ingredients and presented linearity for acyclovir concentrations ranging from 1.25 to 40.0 µg/mL (r = 0.9999). Precision and accuracy data demonstrated good reproducibility. Recovery ranged from 99.3 to 101.2. LOD was 0.08 µg/mL and LOQ, 0.25 µg/mL. Thus, the proposed method proved to be easy, low cost, and accurate, and therefore, an useful alternative to quantify acyclovir in nanoparticles

Sensory evaluation of albendazole suspensions

Sensory analysis was used in the albendazole suspension stability study. Three formulations were prepared and stored for 1, 3, and 6 months at 4 ±1, 26 ±1, 37, 50 and 65 ºC. Samples were evaluated through the difference from control sensory test using 24 trained judges in individual cabins. Although albendazole content was not altered in the conditions studied, sensory test showed differences between control and stored samples, except for one of the formulations stored under refrigeration for one month. These results have shown that the sensory evaluation is an important tool for quality control of pharmaceutical preparations, in association with chemical, physicochemical and microbiological tests

Derivative spectrophotometric method for determination of acyclovir in polymeric nanoparticles

A derivative spectrophotometric method was validated for quantification of acyclovir in poly (n-butylcyanoacrylate) (PBCA) nanoparticles. Specificity, linearity, precision, accuracy, recovery, detection (LOD) and quantification (LOQ) limits were established for method validation. First-derivative at 295.2 nm eliminated interferences from nanoparticle ingredients and presented linearity for acyclovir concentrations ranging from 1.25 to 40.0 µg/mL (r = 0.9999). Precision and accuracy data demonstrated good reproducibility. Recovery ranged from 99.3 to 101.2. LOD was 0.08 µg/mL and LOQ, 0.25 µg/mL. Thus, the proposed method proved to be easy, low cost, and accurate, and therefore, an useful alternative to quantify acyclovir in nanoparticles