XXV AEDEM International Conference

Comunicação em CongressoEl objetivo de este trabajo es mostrar las principales evoluciones habidas en el modelo ABC desde su aparición en los años ochenta. El ABC multietapas es una evolución natural para su adaptación al entorno real de las organizaciones, el Time-Driven Activity Based Costing - TDABC es un desarrollo que simplifica el ABC al unificar los inductores de coste en la variable tiempo, y finalmente tenemos el modelo Resource Consumption Accounting - RCA que hibrida el ABC con el modelo GPK alemán. Esta ponencia expondrá los tres modelo pero extendiéndose especialmente en el modelo RCA al ser éste el menos conocido y expandido en la práctica de las organizaciones.info:eu-repo/semantics/publishedVersio

Average bioequivalence of single 500 mg doses of two oral formulations of levofloxacin: a randomized, open-label, two-period crossover study in healthy adult Brazilian volunteers

Average bioequivalence of two 500 mg levofloxacin formulations available in Brazil, Tavanic(c) (Sanofi-Aventis Farmacêutica Ltda, Brazil, reference product) and Levaquin(c) (Janssen-Cilag Farmacêutica Ltda, Brazil, test product) was evaluated by means of a randomized, open-label, 2-way crossover study performed in 26 healthy Brazilian volunteers under fasting conditions. A single dose of 500 mg levofloxacin tablets was orally administered, and blood samples were collected over a period of 48 hours. Levofloxacin plasmatic concentrations were determined using a validated HPLC method. Pharmacokinetic parameters Cmax, Tmax, Kel, T1/2el, AUC0-t and AUC0-inf were calculated using noncompartmental analysis. Bioequivalence was determined by calculating 90% confidence intervals (90% CI) for the ratio of Cmax, AUC0-t and AUC0-inf values for test and reference products, using logarithmic transformed data. Tolerability was assessed by monitoring vital signs and laboratory analysis results, by subject interviews and by spontaneous report of adverse events. 90% CIs for Cmax, AUC0-t and AUC0-inf were 92.1% - 108.2%, 90.7% - 98.0%, and 94.8% - 100.0%, respectively. Observed adverse events were nausea and headache. It was concluded that Tavanic(c) and Levaquin(c) are bioequivalent, since 90% CIs are within the 80% - 125% interval proposed by regulatory agencies.A bioequivalência média de duas formulações de levofloxacino disponíveis no Brasil, Tavanic(c) (Sanofi-Aventis Farmacêutica Ltda, Brasil, produto referência) e Levaquin(c) (Janssen-Cilag Farmacêutica Ltda, Brasil, produto teste) foi determinada por meio da realização de ensaio aleatório, aberto, cruzado, com dois períodos e duas sequências, em 26 voluntários sadios em condições de jejum. Amostras de sangue dos voluntários foram obtidas ao longo de um período de 48 horas após administração de dose única de 500 mg de levofloxacino. As concentrações plasmáticas do fármaco foram determinadas por método cromatográfico validado. Os parâmetros farmacocinéticos Cmax, Tmax, Kel, T1/2el, AUC0-t e AUC0-inf foram calculados por análise não compartimental. A bioequivalência foi determinada pelo cálculo de intervalos de confiança 90% (IC 90%) para as razões entre os valores de Cmax, AUC0-t e AUC0-inf obtidos para os produtos teste e referência, usando dados transformados logaritmicamente. A tolerabilidade foi avaliada pelo acompanhamento dos sinais vitais e resultados de exames laboratoriais, por consultas e por relato espontâneo dos voluntários. ICs 90% para Cmax, AUC0-t e AUC0-inf foram 92.1% - 108.2%, 90.7% - 98.0%, e 94.8% - 100.0%, respectivamente. Os eventos adversos observados foram náusea e cefaleia. Concluiu-se que os produtos Tavanic(c) e Levaquin(c) são bioequivalentes, uma vez que os ICs 90% estão dentro da faixa de 80%-125% proposta pelas agências reguladora

Método analítico para a determinação de meloxicam em plasma humano por cromatografia líquida de alta eficiência (CLAE)

A simple, rapid and specific high-performance liquid cromatographic (HPLC) method was developed and validated to estimate meloxicam (COX-2 inhibitor) levels in human plasma. Piroxicam was used as internal standard. Reversed phase chromatography was conducted using a Synergi RP-MAX (150 x 4.6 mm) column at 30 ºC and a mobile phase of acetonitrile and 0.025 mol/L pH 4,5 phosphate buffer (40:60, v/v), at a flow rate of 1mL/min. Analytes were detected at 364 nm. Plasma samples were acidified with 1 mol/L hydrochloric acid and extracted with tert-butyl methyl ether, evaporated to dryness, reconstituted in 250 mL of mobile phase and injected in the column. The retention time of meloxicam and piroxicam were 3.35 and 4.19 minutes, respectively. This method showed to be linear in the range of 50 - 4500 ng/mL (R² = 0.9995), a LOQ of 50 ng/mL and accuracy of 114%. The analytical method showed suitable specificity, sensitivity, linearity, precision and accuracy, and can be used in bioequivalence or pharmacokinetics studies involving meloxicam.Desenvolveu-se e validou-se método analítico simples, rápido e específico para quantificação de meloxicam (inibidor da COX-2) em plasma humano através da cromatografia líquida de alta eficiência, para aplicação em estudos de bioequivalência. Piroxicam foi utilizado como padrão interno. Empregou-se cromatografia em fase reversa com coluna modelo Synergi RP-MAX (150 x 4,6 mm), à temperatura de 30 ºC e fase móvel constituída por mistura de acetonitrila e tampão fosfato 0,025 mol/L pH 4,5 (40:60, v/v), a um fluxo de 1,0 mL/min. Os analitos foram detectados por UV a 364 nm. As amostras de plasma foram acidificadas com ácido clorídrico 1 mol/L, extraídas utilizando-se éter terc-butil metílico e, após filtração e secagem, o resíduo foi reconstituído em 250 mL de fase móvel para injeção em CLAE. Os tempos de retenção para meloxicam (padrão) e piroxicam (padrão interno) foram 3,35 e 4,19 minutos, respectivamente. Este método apresentou linearidade na faixa de concentração entre 50-4000 ng/mL (R² = 0,9995), com limite de quantificação inferior de 50 ng/mL e exatidão de 114%. O método analítico desenvolvido neste trabalho demonstrou especificidade, linearidade, precisão e exatidão adequadas, permitindo sua aplicação em ensaios de bioequivalência

Evaluation of the effects on different doses and sampling schedules on the assessment of bioequivalence

Os estudos de bioequivalência são realizados em humanos, por meio da administração dos medicamentos em estudo pela mesma via extravascular, sob condições experimentais padronizadas, seguida pela determinação das concentrações plasmáticas do fármaco em função do tempo. Nestes estudos considera-se que curvas estatisticamente semelhantes de decaimento sanguíneo de fármacos produzem o mesmo resultado em termos de eficácia e segurança. A partir das curvas de concentração em função do tempo obtidas, determinam-se os parâmetros farmacocinéticos Cmax, tmax e ASC. A bioequivalência entre dois produtos é estabelecida por meio do IC 90%, que deve estar entre 80 a 125% para os parâmetros farmacocinéticos Cmax e ASC. O cronograma de coleta de amostras biológicas é um dos aspectos mais críticos no planejamento de estudos de bioequivalência, pois este afeta diretamente a determinação dos parâmetros farmacocinéticos utilizados na avaliação da bioequivalência. Outro aspecto importante relacionado a este tipo de estudo é a diferença de teor entre os produtos a serem submetidos ao estudo de bioequivalência, que segundo a legislação brasileira vigente, deve ser menor ou igual a 5%. Neste trabalho foram avaliados diferentes cronogramas de coleta de amostras sangue, avaliando-se o impacto destes no resultado final de um estudo de bioequivalência e, além disso, a influência da diferença de teor de fármaco entre dois produtos que levaria à bioinequivalência também foi investigada. Para tanto simulações matemáticas e um estudo in vivo foram conduzidos. O fármaco modelo escolhido foi a cefadroxila, por apresentar características farmacocinéticas e farmacodinâmicas ideais. O programa Microsoft Office Excel 2003 foi utilizado para simular as concentrações plasmáticas e determinar o IC 90%. As simulações foram feitas por meio de dois modelos: modelo baseado em máximos e mínimos de parâmetros farmacocinéticos, e modelo baseado em coeficientes de variação intra e inter-individuais do fármaco. Dez diferentes doses, entre -10% a 20% da dose referência, e 6 cronogramas de coleta foram avaliados. O estudo in vivo foi realizado com quatro doses diferentes de cefadroxila. A bioequivalência entre as doses e em diferentes cronogramas de coleta foi avaliada em 24 voluntários sadios do sexo masculino. Os voluntários receberam as quatro doses do estudo em desenho cruzado, em quatro períodos e quatro seqüências, com washout de 7 dias entre as doses. As concentrações plasmáticas de cefadroxila, até 8 horas após a administração, foram determinadas por cromatografia líquida de alta eficiência com detecção DAD. Os parâmetros farmacocinéticos tmax, Cmax e AUC0-t foram determinados nas diferentes doses e cronogramas de coleta, sendo que o critério para estabelecer-se a bioequivalência foi baseada nos resultados do IC 90% dos parâmetros farmacocinéticos Cmax e AUC0-t. Os resultados obtidos nas simulações mostraram boa correlação com os dados reais obtidos a partir de estudos in vivo. As simulações baseadas em coeficientes de variação intra e inter-individuais descreveram melhor os resultados observados no estudo in vivo. De acordo com os resultados obtidos no estudo in vivo pode-se concluir que cronogramas de coletas com menos amostras são tão eficientes quanto cronogramas de coletas com mais amostras, desde que o tempo de tmax esteja incluído. Em relação ao teor de fármaco, concluiu-se que dois produtos com diferença de teor menor ou igual a 11% ainda são bioequivalentes e que diferença maior ou igual a 14% resultam em bioinequivalência. Observou-se ainda que o parâmetro farmacocinético ASC0-t é mais sensível que Cmax para detectar diferenças.Bioequivalence studies are designed to compare the in vivo performance of different formulations of the same drug or different drug products by a randomized crossover study. Pharmacokinetic parameters are obtained from the drug concentration-time profile in blood, serum, or plasma. The most frequently used pharmacokinetic parameters are area under the plasma or blood concentration-time curve (AUC), maximum concentration (Cmax) and time to achieve maximum concentration (tmax). Bioequivalence is concluded if the average bioavailability of the test formulation is within (80%, 125%) that of the reference formulation, with a certain assurance, that is, an equivalence criterion of 80% to 125% for assessment of bioequivalence based on the ratio of average bioavailability is employed. The logarithmic transformation is used for AUC and Cmax. Accuracy in measuring pharmacokinetics parameters directly affects accuracy of bioequivalence tests. Since the number of blood samples per patient is limited, sampling points should be chosen such that the time concentration profile is adequately defined so as to allow the calculation of relevant parameters. According to guidelines proposed by the National Agency of Sanitary Vigilance of Brazil (ANVISA), bioequivalence studies can be conducted only if the difference in drug content between the reference and test product is less than or equal to 5%. The goals of this study are to evaluate the influence of differences in amount of active moiety present in the formulation and possibility of reducing the number of sampling points in bioequivalence studies and to discuss the impact of these parameters in bioequivalence conclusions. For these approaches, simulations and an in vivo study were done. The drug selected was cefadroxil. Cefadroxil presents ideal pharmacokinetics and pharmacodynamics characteristics for this kind of study, such as high bioavailability, low intra and intersubject variability, short elimination rate and wide therapeutic range. Microsoft Office Excel 2003 software was used to simulate drug concentration-time profiles for different doses and several sampling schedules, and to determine 90% confidence interval. Simulations were done by two models: a) based on assumed maximum and minimum pharmacokinetic parameters values; b) based on assumed intra and intersubject variability. Ten different doses, ranging from -10% to 20% of the reference dose, and six sampling schedules were evaluated. The in vivo study was performed with four different cefadroxil doses. Their relative bioavailability were evaluated in 24 healthy volunteers who received a single oral dose of each preparation. An open, randomized clinical trial designed as four-periods and four sequences crossover with 7-days washout between doses was employed. Plasma samples for assessments of their cefadroxil concentration by HPLC-DAD were obtained over 8 h after administration. Pharmacokinetics parameters tmax, Cmax and AUC0-t were evaluated using different doses and sampling schedules. For the purpose of bioequivalence analysis Cmax and AUC0-t were considered. For each schedule, to claim bioequivalence in average bioavailability, a 90% confidence interval was constructed for ratio of average between test and reference products and compared with (80%, 125%) limits. If the constructed confidence interval falls within the limits, then the two formulations are considered bioequivalent. The results obtained by simulate time-concentration profiles, showed good correlation with real data. Comparing the results obtained through in vivo study and the two simulations models, the simulations based in intra and intersubject variability was more predictive. In conclusion, no significant differences were found between sampling schedules evaluated, since the sampling time around tmax were maintained in sampling schedules. Bioinequivalence was observed when the difference between cefadroxil doses was higher than 14%. The parameter AUC0-t was more sensitive than Cmax to detect differences

LC-UV Methodology for Simultaneous Determination of Lamivudine and Zidovudine in Plasma by Liquid-Liquid Extraction

This study describes an accurate, sensitive, and specific chromatographic method for the simultaneous quantitative determination of lamivudine and zidovudine in human blood plasma, using stavudine as an internal standard. The chromatographic separation was performed using a C8 column (150 x 4.6 mm, 5 mu m), and ultraviolet absorbency detection at 270 nm with gradient elution. Two mobile phases were used. Phase A contained 10 mM potassium phosphate and 3% acetonitrile, whereas Phase B contained methanol. A linear gradient was used with a variability of A-B phase proportion from 98-2% to 72-28%, respectively. The drug extraction was performed with two 4 mL aliquots of ethyl acetate.CAPESFURPUFOPUniversidade de São Paulo - BIOFAR/FCF/US

Bioequivalence study of two oral formulations of cefadroxil in healthy volunteers

Two different cefadroxil (CAS 50370-12-2) formulations were evaluated for their relative bioavailability in 24 healthy volunteers who received a single 500 mg oral dose of each preparation. An open, randomized clinical trial designed as a two-period crossover study with a 7-day washout period between doses was employed. Plasma samples for assessments of their cefadroxil concentration by HPLC-UV were obtained over 8 h after administration. Values of 48.94 +/- 10.18 mu g . h/ml for test, and 48.51 +/- 9.02 mu g . h/ml for the reference preparation AUC(0-t) demonstrate a nearly identical extend of drug absorption. Maximum plasma concentration C-max of 16.04 +/- 4.94 mu g/ml and 16.01 +/- 4.02 mu g/ml achieved for the test and reference preparations did not differ significantly. The parametric 90% confidence intervals (CI) of the mean of the difference (test-reference) between log-transformed values of the two formulations were 96.80% to 104.51% and 92.01% to 107.00% for AUC(0-t) and C-max, respectively. Since for both AUC(0-t) or C-max the 90% CI values are within the interval proposed by the Food and Drug Administration, the test product is bioequivalent to the reference product for both the rate and extent of absorption after single dose administration

AN EFFICIENT HPLC-UV METHOD FOR THE QUANTITATIVE DETERMINATION OF CEFADROXIL IN HUMAN PLASMA AND ITS APPLICATION IN PHARMACOKINETIC STUDIES

Cefadroxil is a semi-synthetic first-generation oral cephalosporin used in the treatment of mild to moderate infections of the respiratory and urinary tracts, skin and soft tissue infections. In this work a simple, rapid, economic and sensitive HPLC-UV method is described for the quantitative determination of cefadroxil in human plasma samples using lamivudine as internal standard. Sample pre-treatment was accomplished through protein precipitation with acetonitrile and chromatographic separation was performed with a mobile phase consisting of a mixture of sodium dihydrogen phosphate monohydrate solution, methanol and acetonitrile in the ratio of 90:8:2 (v/v/v) at a flow rate of 1.0mL/min. The proposed method is linear between 0.4 to 40.0 mu g/mL and its average recovery is 102.21% for cefadroxil and 97.94% for lamivudine. The method is simple, sensitive, reproducible, less time consuming for determination of cefadroxil in human plasma. The method can therefore be recommended for pharmacokinetics studies, including bioavailability and bioequivalence studies.FAPESP (Sao Paulo, Brazil)FAPESP (Sao Paulo, Brazil

Bioequivalence Evaluation of Two Different Tablet Formulations of Tinidazole in Healthy Volunteers

The bioequivalence of two different tablet formulations of tirtidazole (CAS 19387-91-8) was determined in healthy volunteers after a single dose in a randomized crossover study, with a 1-week washout period between the doses. Reference and test products were administered to 24 volunteers with 240 mL water after overnight fasting. Plasma concentrations of tinidazole were monitored by a high-performance liquid chromatographic method (HPLC) over a period of 72 h after the administration. The pharmacokinetic parameters AUC(0-t), AUC(0-infinity), C(max), T(max), T((1/2)el) and beta were determined from plasma concentration time profile of both formulations and found to be in good agreement with previously reported values. The calculated pharmacokinetic parameters were compared statistically to evaluate bioequivalence between the two brands. The analysis of variance (ANOVA) did not show any significant difference between the two formulations and 90% confidence intervals for the ratio of C(max) (93.9 - 102.6%), AUC(0-t), (94.9-101.1%) and AUC(0-infinity) (94.6-100.8%) values for the test and reference products were within the 80 - 125% interval, satisfying bioequivalence criteria of the European Committee for Proprietary Medicinal Products and the US Food and Drug Administration Guidelines. These results indicate that the test and the reference products of tinidazole are bioequivalent and, thus, may be prescribed interchangeably