Serum activity/concentration profiles of a sustained-released formulation of sulphathiazole-trimethoprim (2.5:1) in calves.

Thirty-six two-week-old healthy Holstein-Friesian calves weighing between 52 and 58 kg were divided at random into three groups of 12; group A calves were given a single oral bolus containing 2.5 g sulphathiazole and 1 g trimethoprim in a sustained-release formulation; group B received the same doses of the drugs but the trimethoprim was not in a sustained-release formulation; group C received a bolus containing 2.5 g sulphathiazole and 0.5 g conventional trimethoprim. Blood samples were collected at intervals for two days, the serum was separated and the composite antibacterial activity profiles of the mixture were analysed by an agar-diffusion microbiological method. The mean maximum activities in the serum of the three groups were 23.4 microg/ml in group A, 9.25 microg/ml in group B and 8.01 microg/ml in group C. The mean areas under the curves of the serum activity time curves were 838 microg/ml/hour in group A, 216 microg/ml/hour in group B and 182 microg/ml/hour in group C.

Depletion study of trimethoprim and sulphadiazine in milk and its relationship with mastitis pathogenic bacteria strains minimum inhibitory concentrations (MICs) in dairy cows.

Time-related concentrations in milk of a combination of trimethoprim-sulphadiazine (TMP-SDZ) intramammary formulated infusion and its relationship with pathogenic bacteria strains minimum inhibitory concentrations (MICs) isolated from clinical mastitis cows were analysed. The MICs study was performed for Escherichia coli, Staphylococcus aureus and Streptococcus sp. strains. The SDZ concentrations in milk were analysed using high-performance liquid chromatography (HPLC) and TMP using a microbiological assay. Ten lactating cows milked three times daily were used in the time-concentration studies of TMP-SDZ. Milk samples (approximately 20 mL) from the treated mammary quarters were taken at 6, 12, 24, 30 and 36 h after first administration. In order to define the withdrawal time, milk samples from the treated mammary quarters were taken at 24, 36, 48, 72, 84 and 96 h, after finishing the therapy. The MICs fluctuated between 1 and 8 microg/mL. Effective therapeutic concentrations lasted for 36 h when intramammary infusion was repeated three times every 12 h. No TMP was detected in milk for 24 h after finishing therapy. Milk SDZ concentrations were below 0.1 microg/mL in all treated cows after 84 h finishing therapy. At 96 h after finishing therapy, no SDZ milk concentrations were found in six animals, although four animals of the experimental group still had concentrations of 0.07 microg/mL.

Farmacocinética de tres mezclas de sulfonamidas con trimetroprim en cerdos, mediante una técnica cualitativa-cuantitativa / Pharmacokinetics of three sulfonamide-trimethoprim mixtures in pigs

Con la finalidad de evaluar la farmacocinética de tres mezclas de sulfonamida con trimetroprim, se utilizaron 21 cerdos criollos de 20 kg de peso, divididos al azar en tres grupos de 7 cerdos cada uno. A los siete cerdos de cada grupo se les administró, por vía iv en una primera fase y por vía oral (dosis bolo) 15 días después, 100 mg/kg de las siguientes mezclas: sulfacloropiridazina-trimetroprim (SCP-TMP); sulfamonometoxina-trimetroprim (SMM-TMP) y sulfametoxazol-trimetroprim (SMZ-TMP). Después de la dosificación se obtuvieron muestras de sangre de las venas auriculares a intervalos crecientes hasta las 12 horas. Se obtuvieron los sueros por coagulación y centrifugación y se congelaron a -4º C hasta su análisis. La cuantificación se realizó mediante un análisis bacteriológico por difusión en placa, utilizando suero de cerdo como vehículo y una cepa sensible de Escherichia coli como organismo problema, con un coeficiente de variación intraprueba de 8 por ciento. Se realizaron análisis de farmacocinética compartamental por computadora. Los resultados indican una mayor biodisponibilidad para la SCP-TMP, mayores valores en la concentración sérica máxima y mejores volúmenes de distribución. Aunque la vida media de eliminación fue ligeramente mayor para SMM-TMP y SMZ-TMP, la depuración no varió sustancialmente entre las tres mezclas. Se concluye que existen importantes diferencias en la farmacocinética de mezclas que pudieran aparentar ser bioequivalentes; y se comenta sobre el impacto de estas variaciones en la respuesta clínica

Estudio comparativo: Lomefloxacina versus trimetoprim/sulfametoxazol en el tratamiento de infecciones no complicadas del aparato urinario / Lomefloxazine versus trimetoprim/sulfametoxazole in non-complicated urinary tract infections: a comparative studyç

La lomefloxacina, un antibiótico difluorinado y derivado de las quinolonas, fue estudiado comparativamente contra trimetoprim/sulfametoxasol (TMP/SMX) en el tratamiento de infecciones no complicadas del aparato urinario. El estudio fué prospectivo, controlado, al azar y en forma ciega sencilla. Se trataron 28 pacientes con lomefloxacina y 29 con TMP/SMX, con un rango de edades de 18 a 65 años. Los resultados mostraron en el grupo de la iomefloxacina, 93% de curaciones y 7% de mejorías clínicas con 96% de erradicación del agente patógeno y 4% de persistencia. En tanto que en grupo tratado con TMP/SMX, se observó 55% de curaciones, 34% de mejorías clínicas y 7% de fracasos; la erradicación del agente causal se logró en 85% de los casos con una persistencia de patógeno inicial en 15%. La respuesta clínica fué mejor en el grupo de la lomefloxacina (P<0.02) y la erradicación bacteriana se observó en una fase más temprana. Se concluye que la lomefloxacina es un antimicrobiano eficaz y seguro en el tratamiento de las infecciones no complicadas del tracto urinario

Pharmacokinetics of sulfamethoxazole and trimethoprim in Mexicans: bioequivalence of two oral formulations (URO-TS D and Bactrim F).

Two oral pharmaceutical formulations (URO-TS D and Bactrim F) containing 800 mg of sulfamethoxazole (SMZ) and 160 mg of trimethoprim (TMP) were given to 10 Mexican healthy volunteers, following a randomized cross-over design. Blood and urine samples were obtained, concentrations of TMP, SMZ, and its metabolite N4-acetyl SMZ were measured by HPLC and pharmacokinetic analyses were performed. The observed Cmax, tmax, half-life, AUC, and cumulative urinary excretion values for the three compounds studied were within the ranges that have been previously reported for European and North American subjects. Therefore, it appears that pharmacokinetics of SMZ and TMP in Mexicans are similar to those observed in Caucasian populations. When the two studied formulations were compared, no statistically significant differences were detected in any pharmacokinetic parameter. Therefore, it is concluded that both brands tested are bioequivalent. Moreover, these two formulations manufactured in Mexico yield SMZ and TMP plasma and urine levels similar to those obtained with equivalent formulations of European or North American origin.