Reversed phase HPLC determination of tamoxifen in dog plasma and its pharmaco-kinetics after a single oral dose administration

The analytical method developed to evaluate tamoxifen in dog plasma samples was precise, accurate, robust and linear in the range of 5-200 ng/mL. The limits of detection and quantification were 0.981 ng/mL and 2.97 ng/mL, respectively. Besides, the intra-day precision and accuracy variations were 8.78 and 10.16%, respectively. Tamoxifen concentrations were analyzed by combined reversed phase liquid chromatography and UV detection (lambda=280 nm). The study was conducted using an open randomized 2-period crossover balanced design with a 1-week washout period between the doses. This simple, rapid and selective method is suitable for pharmacokinetic, bioavailability and bioequivalence studies

Evaluation of Microbial Reduction in Root Canals Instrumented with Reciprocating and Rotary Systems

Svrha: Ovim istraživanjem in vitro željela se procijeniti učinkovitost dezinfekcije korijenskih kanala nakon instrumentacije sistemom ReciprocTM i ProTaper UniversalTM, uz irigaciju 1-postotnim natrijevim hipokloritom (NaOCl). Materijali i metode: Četrdeset kanala jednokorijenskih mandibularnih premolara inficirano je bakterijama Enterococcus faecalis, Pseudomonas aeruginosa, Staphylococcus aureus i Candida albicans, a dvadeset kanala ostavljeno je bez infekcije. Uzorci su nasumično podijeljeni u šest grupa (n = 10): grupa 1: ProTaper UniversalTM + 1-postotni NaOCl; grupa 2 (pozitivna kontrola): ProTaper UniversalTM + fiziološka otopina; grupa 3 (negativna kontrola bez mikroorganizama): ProTaper UniversalTM + fiziološka otopina; grupa 4: ReciprocTM + 1-postotni NaOCl; grupa 5 (pozitivna kontrola): ReciprocTM + fiziološka otopina; grupa 6 (negativna kontrola bez mikroorganizama): ReciprocTM + fiziološka otopina. Rezultati: Kombinacija sistema ProTaper UniversalTM i 1-postotnog natrijeva hipoklorita potpuno je eliminirala sve mikroorganizme. Rast mikroorganizama uočen je pri korištenju sistema ReciprocTM i 1-postotnog natrijeva hipoklorita. Zaključak: Protokoli provedeni u ovom istraživanju pokazali su da sistem ReciprocTM uz 1-postotni NaOCl nije uspio u cijelosti eliminirati iz korijenskih kanala E. faecalis, P. aeruginosa, S. aureus i C. albicans.Objective: This in vitro study aimed to evaluate the efficacy of the disinfection of root canal systems carried out with ReciprocTM and ProTaper UniversalTM systems using 1% sodium hypochlorite (NaOCl). Methods: Forty human single-rooted mandibular premolars were infected with Enterococcus faecalis, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans, and twenty were not infected. The specimens were randomly divided into 6 groups (n = 10): Group 1: ProTaper UniversalTM + 1% NaOCl; Group 2 (positive control): ProTaper UniversalTM + saline; Group 3 (negative control without microorganisms): ProTaper UniversalTM + saline; Group 4: ReciprocTM + 1% NaOCl; Group 5 (positive control): ReciprocTM + saline; Group 6 (negative control without microorganisms): ReciprocTM + saline. Samples were collected before and after the completion of specific treatments, and plated in specific media cultures. The Fisher exact test was used for the statistical analysis of differences in terms of presence or absence of microbial growth among groups. For all tested pathogens, significant differences (p < 0.001) were verified between the instrumentation systems used. Results: ProTaper UniversalTM associated with 1% NaOCl completely eliminated all microorganisms. Microbial growth, however, was observed when ReciprocTM was used associated with 1% NaOCl. Conclusion: According to the protocol executed for this study, the ReciprocTM system associated with 1% NaOCl was not able to completely eliminate E. faecalis, P. aeruginosa, S. aureus and C. albicans from the root canal systems

Desenvolvimento de formulações e tecnologia de obtenção de comprimidos revestidos de efavirenz: terapia anti-HIV

O efavirenz é uma das mais recentes classes de agentes anti-retrovirais aplicados no tratamento de infecções por HIV. Está entre os medicamentos de primeira escolha no tratamento da AIDS. Como o efavirenz possui característica hidrofóbica, baixa densidade e oferece grande resistência ao escoamento, a escolha de uma formulação adequada deste fármaco é essencial no desenvolvimento dos comprimidos e para garantir melhor disponibilização no trato gastrointestinal, de forma a alcançar a biodisponibilidade e o efeito terapêutico desejados. Neste trabalho, apresentamos, de forma lógica, o desenvolvimento tecnológico de comprimidos revestidos de efavirenz, levando em consideração suas características físicas e físico-químicas. Os núcleos (comprimidos) de efavirenz foram obtidos utilizando-se a técnica de granulação por via úmida. No revestimento por película utilizou-se Opadry® Y-1-7000 em sistema aquoso. Os parâmetros adotados para avaliação física dos comprimidos seguiram as especificações farmacopéicas oficiais e a determinação quantitativa foi realizada mediante método analítico desenvolvido e validado.Efavirenz is one of the most recent classes of anti-retroviral drugs used in the treatment of HIV infections. It is the first choice therapy for AIDS treatment. As efavirenz detains hydrofobic characteristic, low density and offers great resistance to draining, it has been essential to choose an adequated formulation for it, in order to guarantee drug's availability in gastro-intestinal tract, achieving bioavailability and expected therapeutical effects. This work presents efavirez coated tablets thecnological development, considering the physics and physico-chemical characteristics of this drug. The efavirez nucleus (tablets) has been obtained employing granulation technics by humid via. In the coating by film, Opadry Y-1-7000 in aquous system was used. The adopted parameters to tablet phisics evaluation followed official phamacopeial specifications and quantitative determination of the drug was performed by developed and validated methodology

Development and validation of a HPLC analytical assay method for efavirenz tablets: a medicine for HIV infections

O efavirenz é um inibidor não análogo de nucleosídeo da transcriptase reversa, utilizado no tratamento da infecção por HIV. Um método simples, por cromatografia líquida de alta eficiência, foi desenvolvido e validado para quantificação do efavirenz em comprimidos. O desenvolvimento do método levou em consideração as características físico-químicas do efavirenz. O método foi validado seguindo os parâmetros da USP 29. A análise foi realizada por meio de detector ultravioleta, utilizando um comprimento de onda de 252 nm, com coluna de fase reversa (C18, 250 mm x 3.9 mm, 10 &#956;m) e fase móvel isocrática contendo acetonitrila/água/ácido ortofosfórico (70: 30: 0.1). Os critérios usados para validação foram: seletividade, linearidade, precisão, exatidão, robustez e limites de detecção e quantificação do método. Foi utilizado método estatístico em todas as etapas do processo de validação. Os resultados obtidos mostraram que o método é uma alternativa para quantificação do efavirenz em comprimidos, tornando viável seu uso na rotina industrial e laboratórios analíticos.Efavirenz is a reverse transcriptase non analog nucleoside inhibitor used to treat HIV infections. A simple assay method by high performance liquid chromatography was developed and validated for efavirenz tablets. The physical chemical characteristics of efavirenz were investigated to developing the method. The method was validated observing the parameters described in USP 29. Analyses were performed by an ultraviolet detector at a 252 nm wavelength, on a reverse-phase column (C18, 250 mm x 3.9 mm, 10 &#956;m), using an isocratic mobile phase containing acetonitrile/water/orthophosphoric acid (70:30:0.1). The validation parameters used were: selectivity, linearity, precision, accuracy, robustness, detection and quantification limits, and all resulting data were treated by a statistical method. The results obtained confirmed an alternative assay method for efavirenz tablets adequate for routine industrial use

Antimicrobial activity of chlorhexidine in root canals instrumented with the ProTaper Universal™ System

Aim: The purpose of the present study was to evaluate the antimicrobial activity of 0.2%, 1%, and 2% chlorhexidine in root canals instrumented with the ProTaper Universal™ system. Methods: Fifty human mandibular premolar teeth were infected with a mixture of Candida albicans, Pseudomonas aeruginosa, Enterococcus faecalis and Staphylococcus aureus. The specimens were randomly divided into 5 groups with 10 root canals according to the irrigant used. All root canals were instrumented with the ProTaper Universal™ system. Assessment of the antimicrobial action of the irrigant was performed before, during, and after instrumentation. Data were analyzed statistically by Chi-squared test and the Fisher exact test at 5% significance level. Results: The 0.2% chlorhexidine solution was ineffective against all test microorganisms. The 1% chlorhexidine solution was effective in eliminating P. aeruginosa and C. albicans after the use of the F1 and F3 instruments, respectively. The 2% chlorhexidine solution was effective at killing S. aureus, P. aeruginosa and C. albicans after the use of the S1 instrument. There were statistically significant differences (p<0.05) between the concentrations of chlorhexidine and the instruments used. Conclusions: The 0.2% chlorhexidine solution in combination with rotary instrumentation was ineffective against all test microorganisms. The 1% chlorhexidine solution was ineffective against S. aureus and E. faecalis. The 2% chlorhexidine solution was not sufficient to inactivate E. faecalis

Antimicrobial activity of chlorhexidine in root canals instrumented with the ProTaper Universal System

e purpose of the present study was to evaluate the antimicrobial activity of 0.2%, 1%, and 2% chlorhexidine in root canals instrumented with the ProTaper Universal system. Methods: Fifty human mandibular premolar teeth were infected with a mixture of Candida albicans, Pseudomonas aeruginosa, Enterococcus faecalis and Staphylococcus aureus. The specimens were randomly divided into 5 groups with 10 root canals according to the irrigant used. All root canals were instrumented with the ProTaper Universal system. Assessment of the antimicrobial action of the irrigant was performed before, during, and after instrumentation. Data were analyzed statistically by Chi-squared test and the Fisher exact test at 5% significance level. Results: The 0.2% chlorhexidine solution was ineffective against all test microorganisms. The 1% chlorhexidine solution was effective in eliminating P. aeruginosa and C. albicans after the use of the F1 and F3 instruments, respectively. The 2% chlorhexidine solution was effective at killing S. aureus, P. aeruginosa and C. albicans after the use of the S1 instrument. There were statistically significant differences (p<0.05) between the concentrations of chlorhexidine and the instruments used. Conclusions: The 0.2% chlorhexidine solution in combination with rotary instrumentation was ineffective against all test microorganisms. The 1% chlorhexidine solution was ineffective against S. aureus and E. faecalis. The 2% chlorhexidine solution was not sufficient to inactivate E. faecalis

Caracterização físico-química do potencial agente antineoplásico β-lapachona

A β-lapachona tem inspirado uma série de trabalhos científicos, tendo em vista os inúmeros estudos farmacológicos relatados na literatura, que comprovam suas atividades antibacteriana, antifúngica, antitripanossômica, antiviral, antiinflamatória e antineoplásica. Devido a sua potente atividade anticancerígena, este fármaco encontrase, atualmente, em estudo clínico de fase II para o tratamento de câncer pancreático. O objetivo deste estudo foi determinar as propriedades físico-químicas deste ativo com o emprego de diversas ferramentas analíticas, como, difração de Raios X, infravermelho, análises térmicas, microscopia eletrônica de varredura e ensaio de dissolução. Os resultados obtidos na difração de raios X revelaram o padrão policristalino do fármaco; o infravermelho identificou os principais grupos funcionais da β-lapachona; os dados das análises térmicas apresentaram características de um produto cristalino e de alta pureza; a eletromicrografia demonstrou sua forma cristalina, como cristais acidulares bem definidos de tamanho regular, corroborando com os dados do difratograma. No estudo de dissolução comprovamos que a β-lapachona é praticamente insolúvel em água, sendo necessário o desenvolvimento de estratégias tecnológicas destinadas a melhorar a sua solubilidade em meio aquoso. Dessa forma, a determinação das principais características físico-químicas da β-lapachona será extremamente útil na identificação de problemas que possam vir a surgir durante a formulação e auxiliará no desenvolvimento de formas farmacêuticas mais eficazes e com qualidade