Application of capillary electrophoresis to the simultaneous determination and stability study of four extensively used penicillin derivatives

The applicability of capillary electrophoresis for the analysis of four extensively used penicillin derivatives (benzylpenicillin, ampicillin, amoxicillin, oxacilllin) has been studied. Because of structural similarities, the electrophoretic behavior of these derivatives is very similar; consequently an efficient separation using the conventional capillary zone electrophoresis is hard to be achieved. Their simultaneous separation was solved by using micellar electrokinetic capillary chromatography, the separation being based on the differential partition of the analytes between the micellar and aqueous phase. Using a buffer solution containing 25 mM sodium tetraborate and 100 mM sodium dodecyl sulfate as surfactant, at a pH of 9.3, applying a voltage of + 25 kV at a temperature of 25 °C, we achieved the simultaneous separation of the studied penicillin derivatives in less then 5 minutes. The separation conditions were optimized and the analytical performance of the method was evaluated in terms of precision, linearity, limit of detection, and quantification. Also, a simple capillary zone electrophoresis method was applied to study the stability of the studied penicillin derivatives in water at different temperatures, using ciprofloxacin hydrochloride as internal standard. It was observed that the extent of the hydrolysis of penicillins in water is highly dependent on the time and also temperature.

Estudou-se a aplicabilidade de electroforese capilar para a análise de quatro derivados de penicilina (benzilpenicilina, ampicilina, amoxicilina, oxacilina) amplamente utilizados. Em razão das semelhanças estruturais, o comportamento electroforético destes derivados é muito semelhante e, por conseguinte, a separação eficaz utilizando a electroforese capilar de zona convencional é difícil de ser efetuada. A separação simultânea foi realizada por cromatografia capilar electrocinética micelar, que se baseia na partição diferencial entre os analitos na fase micelar e aquosa. Utilizando-se solução tampão contendo 25 mM de tetraborato de sódio e 100 mM de dodecil sulfato de sódio, como agente tensioativo, com pH de 9,3, voltagem de +25 kV, à temperatura de 25 °C, obteve-se a separação simultânea das penicilinas estudadas em menos de 5 minutos. As condições de separação foram otimizadas e o desempenho do método analítico foi avaliado em termos de precisão, linearidade, limite de detecção e de quantificação. Além disso, aplicou-se método de electroforese capilar de zona simples para estudar a estabilidade de penicilinas em água a diferentes temperaturas, utilizando cloridrato de ciprofloxacino como padrão interno. Estabeleceu-se que o grau de hidrólise de penicilinas em água é altamente dependente do tempo e também da temperatura.

Antibiotic-associated hemorrhagic colitis without Clostridium difficile toxin in children.

We describe nine children with antibiotic-associated hemorrhagic colitis without Clostridium difficile toxin. The onset was usually sudden, with severe hematochezia and abdominal cramps. The illness quickly resolved and required no specific treatment except discontinuation of the implicated antibiotic. Early proctosigmoidoscopy was a useful diagnostic adjunct. It appears that antibiotic-associated hemorrhagic colitis is a distinct entity rather than a variant of antibiotic-associated colitis in children.

Measuring the comparative efficacy of antibacterial agents for acute otitis media: the "Pollyanna phenomenon".

In randomized, double-blind trials of antibiotic therapy for acute otitis media that determined both clinical and bacteriologic outcomes, clinical success rates were (93%) 236 of 253 for patients with bacteriologic success, (62%) 25 of 40 for those with bacteriologic failure, and (80%) 124 of 155 for those with nonbacterial acute otitis media. These rates were used to calculate the effectiveness of three strategies for assessing drug efficacy: (1) tympanocentesis and culture before and during therapy (bacteriologic efficacy), (2) tympanocentesis before therapy and assessment of clinical efficacy in bacterial acute otitis media, and (3) no tympanocentesis and assessment of clinical efficacy in clinical (total) acute otitis media. For a drug with a bacteriologic efficacy of 100%, calculated clinical efficacy was 93% for bacterial acute otitis media and 89% for clinical acute otitis media. For a drug with bacteriologic efficacy of 27%, a rate consistent with no antibacterial therapy, efficacy was 71% for bacterial acute otitis media and 74% for clinical acute otitis media. We conclude that if efficacy is measured by symptomatic response, drugs with excellent antibacterial activity will appear less efficacious than they really are and drugs with poor antibacterial activity will appear more efficacious than they really are. The predominant phenomenon is that drugs with poor antibacterial activity will appear to be clinically effective in the treatment of acute otitis media.

Bacampicilina y amoxicilina en infecciones del tracto respiratorio superior: uso terapeutico comparativo / Bacampicillin and amoxycillin in infection of the upper respiratory tract: comparative therapeutic use

Evaluacion de la eficacia terapeutica, velocidad de respuesta y tolerancia clinica de la bacampicilina (administrada dos veces diarias), en comparacion con la amoxicilina (administrada tres veces al dia), en el tratamiento de infecciones del tracto respiratorio superior

Eficacia de la bacampicilina en fiebre tifoidea / Efficiency of bacampicililin in typhoid fever

Cincuenta y siete pacientes cuyas edades fluctuaban entre 14 a 60 años de edad y en quienes se aisló Salmonella typhi o Salmonella paratyphi fueron incluidos en un estudio abierto para valorar la eficacia de clorhidrato de bacampicilina oral en el tratamiento de fiebre tifoidea, en especial causado por S. typhi. Los pacientes fueron valorados tanto clínica como bacteriológicamente y dividios en tres grupos de tratamiento para recibir bacampicilina oral de acuerdo a uno de los tres esquemas de dosis, durante 14 días. Cuarenta y nueve de los 57 (86.0%) pacientes fueron tratados de manera satisfactoria, tres (5.3%) se consideraron como fallas de tratamiento, y cinco (8.8%) experimentaron efectos indeseables que requirieron la descontinuación del fármaco. No hubo recaídas en un periodo de dos meses de seguimiento en 47 pacientes que fueron tratados de manera satisfactoria con bacampicilina. Los datos de cultivos negativos de heces y bilis en la fase temprana del tratamiento y la ausencia de recaídas, muestran que la terapéutica con clorhidrato de bacampicilina es eficaz en este padecimiento

Gonorrhea in preschool- and school-aged children. Report of the prepubertal gonorrhea cooperative study group.

Single-dose antibiotic therapy was evaluated in 108 episodes of culture-confirmed, uncomplicated gonorrhea in 100 prepubertal children. There were 15 boys and 85 girls between 14 months and 14 years of age. Penicillin G procaine, 100,000 units/kg intramuscularly, was compared with amoxicillin trihydrate, 50 mg/kg orally. Probenecid, 25 mg/kg, was given simultaneously. Both drugs provided prompt bacteriological and clinical response. Multiple episodes of gonorrhea, presumably caused by reexposure, occurred in six girls. Oral and anal cultures were negative in all of 47 Costa Rican cases but were commonly positive in US children. Anal cultures yielded gonococci in 52% of girls and 25% of boys, and oral cultures were positive in 18% and 13%, respectively. In three instances, rectal cultures confirmed the diagnosis when vaginal cultures were negative. Gonorrhea should be considered in every child with vaginal or urethral discharge. Single-dose penicillin-probenecid or amoxicillin-probenecid treatment is curative.