RESUMEN
The degradation products of Cefepime dihydrochloride that emerged throughout stress stability studies have been determined, identified and characterized. The two new impurities were detected by gradient reverse-phase high performance liquid chromatography (HPLC), and Impurity-I was formed in the range from 0.2 to 11.0% and Impurity-II range from 0.2 to 3.5%. These impurities have been identified by LC/MS, and were not reported in the literature. These impurities were synthesized, isolated and characterized. Based on the spectral data, the impurities were named (6R,7R)-7-[(Z)-2-(2-amino-4-thiazolyl)-2-(methoxyimino)acetamido]-3-[(1-methyl-1-pyrrolidinium)methyl]-3-cephem-4-carboxylate-1-oxide (Impurity-I); (2RS)-2[[(Z)-2-(2-amino-4-thiazolyl)-2-(methoxyimino)acetamido]-methyl]-1,2,5,7-tetrahydro-7-oxo-4H-furo[3,4-d][1,3]thiazine (Impurity-II). The structures were established unambiguously by independent synthesis and co-injection in HPLC to confirm the retention times and relative retention times. The structural elucidation of these impurities by spectral data ((1)H NMR, (13)C NMR, 2D-NMR (COSY, HSQC and HMBC), LC/MS, TOF-MS, elemental analysis and IR), synthesis, isolation and the formation of these impurities are discussed in detail.
Asunto(s)
Antibacterianos/química , Cefalosporinas/análisis , Furanos/análisis , Tiazinas/análisis , Cefepima , Cefalosporinas/química , Contaminación de Medicamentos , Estabilidad de Medicamentos , Furanos/química , Calor , Estructura Molecular , Oxidación-Reducción , Fotólisis , Tiazinas/químicaRESUMEN
BACKGROUND: Combining low-level treadmill exercise with adenosine infusion may result in fewer bradyarrhythmic complications by increasing sympathetic tone and may improve myocardial perfusion image quality by decreasing background activity. METHODS: Patients referred for outpatient pharmacologic stress myocardial perfusion imaging performed simultaneous treadmill exercise (mean 2.2 metabolic equivalents) throughout 6-minute adenosine infusion (adenosine-exercise n = 507). Patients unable to exercise and those with left bundle branch block received adenosine infusion alone (adenosine-nonexercise n = 286). Adverse reaction data were collected on all patients and compared by sex. Background-to-target activity was calculated in a blinded fashion on 200 randomly selected patients. RESULTS: During the period from April 1996 to December 1998, 507 patients (64%) underwent adenosine-exercise testing, whereas 286 (36%) underwent adenosine-nonexercise testing. Hypotensive and arrhythmic (atrioventricular block, sinus bradycardia, and new onset atrial fibrillation or flutter) adverse reactions occurred less often during adenosine-exercise than during adenosine-nonexercise. Neither death nor myocardial infarction occurred in either group. In the adenosine-exercise group, 2.8% of patients experienced an adverse reaction versus 5.6% of the adenosine-nonexercise group (P = .04). The reduction in adverse reactions occurred in both men and women, although women had significantly more adverse reactions than men (5.7% vs 1.8%, P = .004). Liver/heart and gut/heart ratios were lower in the adenosine-exercise group (1.05+/-0.42 vs. 1.21+/-0.55 , P = .01; 0.61+/-0.21 vs. 0.69+/-0.24, P = .03, respectively). CONCLUSIONS: Compared with adenosine infusion alone, combining low-level treadmill exercise with adenosine in outpatients is safe, better tolerated, and improves image quality. Women were more likely to experience adverse reactions than men.
Asunto(s)
Adenosina/administración & dosificación , Circulación Coronaria , Enfermedad Coronaria/diagnóstico por imagen , Prueba de Esfuerzo , Tomografía Computarizada de Emisión de Fotón Único , Adenosina/efectos adversos , Adulto , Anciano , Anciano de 80 o más Años , Prueba de Esfuerzo/efectos adversos , Femenino , Hemodinámica , Humanos , Infusiones Intravenosas , Masculino , Persona de Mediana Edad , Radiofármacos , Estudios Retrospectivos , Tecnecio Tc 99m Sestamibi , Radioisótopos de TalioRESUMEN
Angioplasty of the distal anastomosis site of a markedly tortuous left internal mammary artery (LIMA)--anterior descending artery is described. Tortuosity of LIMA was negotiated using the Tracker-Seeker catheter guidewire system. Angioplasty was then performed using the conventional technique.