Pharmacokinetic behavior in sheep and cattle of 5-chloro-2-(methylthio)-6-(1-naphthyloxy)-1H-benzimidazole, a new fasciolicide agent.

The physicochemical properties, pK(a), Log P and solubility of compound alpha, (5-chloro-2-(methylthio)-6-(1-naphthyloxy)-1H-benzimidazole), a new fasciolicide agent, were characterized using conventional methods. Also, its pharmacokinetics was evaluated in sheep and cattle. In both species an oral dose of 12 mg/kg was administered. Blood samples were collected during 144 h and analyzed by using an HPLC assay. Results showed that compound alpha is a weak base with a pK(a) value of 2.87 and log P of 1.44. The solubility was very low in aqueous solvents. Pharmacokinetic studies showed that in both species compound alpha could not be detected at any sampling time. The mean half-life (t(1/2)) values of alpha sulphoxide in sheep and cattle were 19.86 and 29.87 h, while the half-life values of alpha sulphone were 19.43 and 46.32 h respectively. C(max) values of alpha sulphoxide did not differ between species while alpha sulphone values were higher in cattle. Plasma protein binding of alpha sulphoxide was between 82% and 86%. These results, combined with the previous efficacy studies, suggest that compound alpha could be a promising fasciolicide agent.

Liquid chromatographic assay for dicloxacillin in plasma.

A simple high-performance liquid chromatographic method for the determination of dicloxacillin in plasma has been developed. The method only requires 0.5 ml of plasma, phosphate buffer solution (pH = 4.7), acidification with 0.5N hydrochloride acid and liquid extraction with dichloromethane. Posterior evaporation of organic under nitrogen steam and redissolution in mobile phase is carried out. The analysis was performed on a Spherisorb C18 (5 microm) column, using methanol -0.05 M phosphate buffer, pH = 4.7 (75:25; v/v) as mobile phase, with ultraviolet detection at 220 nm. Results showed that the assay is sensitive: 0.5 microg/ml. The response is linear in the range of 0.5 - 10 microg/ml. Maximum inter-day coefficient of variation was 12.4%. Mean extraction recovery obtained was 96.95%. Stability studies showed that the loss was not higher than 10%, samples are stable at room temperature for 6 h, at -20 Celsius for 2 months, processed samples were stable at least for 24 h and also after two freeze-thaw cycles. The method has been used to perform pharmacokinetic and bioequivalence studies in humans.

[Criteria for the diagnosis and treatment of chronic rhino-sinusitis in family medicine, otorhinolaryngology, and allergy services]. / Criterios de diagnóstico y tratamiento de la rinosinusitis crónica en servicios de medicina familiar, de otorrinolaringología y de alergia.

BACKGROUND: Rhinosinusitis is an inflammatory response affecting mucosa membrane of nasal cavity of one or more paranasal sinus. Its prevalence is of 14 and 5-13% in adults and children, respectively. Rhinosinusitis causes high rate of scholar and labor absenteeism. OBJECTIVE: To know diagnostic and treatment criteria of rhinosinusitis in units of familial medicine, otolaryngology and allergy. MATERIAL AND METHODS: A series of 25 patients randomly obtained from familial medicine units 21 and 28 of the IMSS, was studied. Diagnosis was assessed according to 1998 Consensus and computed tomography was considered the gold standard. It was performed to all patients and evaluated by a study-blind radiologist. RESULTS: Diagnosis of rhinosinusitis was done by familial medicine unit in 68%, otolaryngology service in 40% and allergy service in 64%. Clinical criteria most used were nasal congestion and anterior and posterior nasal discharge. The more requested examination was computed tomography (38.7%) and in 30% of cases, medical treatment was not prescribed. CONCLUSIONS: Familial physicians, otolaryngologists and allergists use, with low frequency, international criteria for diagnosis and treatment of chronic rhinosinusitis. Otolaryngologists perform other differential diagnosis.

[The use of the International Guidelines for the Diagnosis and Treatment of Asthma (GINA) in clinical practice among family physicians]. / El uso de las Guías internacionales de Diagnóstico y Tratamiento del Asma (GINA) en la práctica clínica de los médicos familiares.

OBJECTIVE: To evaluate the degree of knowledge of family physicians related to the International Guidelines for the Diagnosis and Treatment (GINA) of Asthmatic Patients. MATERIAL AND METHOD: We invited the family physicians from some clinics of Mexico City. A questionnaire was applied to 50 doctors who accepted to participate in the study; they had a 46 year-old age average and a proportion 1:1 between genders. The analysis was carried out with the test r of Pearson. RESULTS: The correlation between general knowledge of asthma and knowledge of GINA was r = 0.022; between the general knowledge of asthma and the specialty of family medicine was r = -0.117; and that among the knowledge on International Guides of Asthma and the specialty of family medicine was r = 0.33. CONCLUSIONS: A scarce knowledge exists on the guides proposed by GINA.

High-performance liquid chromatographic assay for a new fasciolicide agent, alphaBIOF10, in biological fluids.

This paper describes a high-performance liquid chromatographic method with ultraviolet absorbance detection at 304 nm for the determination of 6-chloro-5-(1-naphthyloxy)-2-methylthio benzimidazole (alphaBIOF10) -- a new fasciolicide agent -- and its sulphoxide (SOalphaBIOF10), in plasma and urine. It requires 2 ml of biological fluid, an extraction using Sep-Pak cartridges, and methanol for drug elution. Analysis is performed on a microBondapak C18 (10 microm) column, using methanol-acetonitrile-water (40:30:30, v/v) as the mobile phase. Results showed that the assay is sensitive: 7.2 ng/ml for alphaBIOF10 and SOalphaBIOF10 in plasma and 3.6 ng/ml for both compounds in urine. The response was linear between 0.195 and 12.5 microg/ml. Maximum intra-day coefficient of variation was 5.3%. Recovery obtained was 97.8% for both alphaBIOF10 and SOalphaBIOF10. In urine, recovery was 99.6% and 93.1% for alphaBIOF10 and SOalphaBIOF10 respectively. The method was used to perform a preliminary pharmacokinetic study in two sheep and was found to be satisfactory.