RESUMEN
A rapid, selective, and sensitive gradient HPLC method was developed for the analysis of dissolution samples of levothyroxine sodium tablets. Current USP methodology for levothyroxine (L-T(4)) was not adequate to resolve co-elutants from a variety of levothyroxine drug product formulations. The USP method for analyzing dissolution samples of the drug product has shown significant intra- and inter-day variability. The sources of method variability include chromatographic interferences introduced by the dissolution media and the formulation excipients. In the present work, chromatographic separation of levothyroxine was achieved on an Agilent 1100 Series HPLC with a Waters Nova-pak column (250 mm × 3.9 mm) using a 0.01 M phosphate buffer (pH 3.0)-methanol (55:45, v/v) in a gradient elution mobile phase at a flow rate of 1.0 mL/min and detection UV wavelength of 225 nm. The injection volume was 800 µL and the column temperature was maintained at 28°C. The method was validated according to USP Category I requirements. The validation characteristics included accuracy, precision, specificity, linearity, and analytical range. The standard curve was found to have a linear relationship (r(2)>0.99) over the analytical range of 0.08-0.8 µg/mL. Accuracy ranged from 90 to 110% for low quality control (QC) standards and 95 to 105% for medium and high QC standards. Precision was <2% at all QC levels. The method was found to be accurate, precise, selective, and linear for L-T(4) over the analytical range. The HPLC method was successfully applied to the analysis of dissolution samples of marketed levothyroxine sodium tablets.
Asunto(s)
Excipientes , Hormonas Tiroideas/análisis , Tiroxina/análisis , Calibración , Cromatografía Líquida de Alta Presión , Humanos , Indicadores y Reactivos , Control de Calidad , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , SolubilidadRESUMEN
Occipital lobe infarction secondary to tentorial herniation is a rare but well-recognized complication of posterior cerebral artery interruption during acute hydrocephalus; however, a similar event in which tonsillar herniation leads to symptomatic occlusion of the anterior spinal arteries (ASAs) has not been reported. The authors present the case of a third ventricular colloid cyst in a previously healthy 24-year-old man who presented with symptoms and signs of critically raised intracranial pressure. He subsequently survived the ictus of insults following emergency external cerebrospinal fluid drainage and definitive resection of the colloid cyst, but he sustained occipital lobe and spinal cord infarction despite the absence of systematic hypotension. The presence of watershed cervicothoracic cord infarction on magnetic resonance imaging suggested that the most likely causes were compromise of ASAs during the period of acute hydrocephalus and the accompanying downward brain herniation. To the authors' knowledge, this is the first report to provide evidence that acute hydrocephalus may lead to ASA syndrome.
Asunto(s)
Encefalopatías/complicaciones , Quistes/complicaciones , Hidrocefalia/complicaciones , Infarto/etiología , Médula Espinal/irrigación sanguínea , Tercer Ventrículo , Enfermedad Aguda , Adulto , Encefalopatías/diagnóstico , Encefalopatías/cirugía , Coloides , Quistes/diagnóstico , Quistes/cirugía , Humanos , Hidrocefalia/diagnóstico , Hidrocefalia/cirugía , Infarto/diagnóstico , Masculino , Lóbulo Occipital/irrigación sanguínea , Lóbulo Occipital/diagnóstico por imagen , Lóbulo Occipital/patología , Radiografía , Médula Espinal/diagnóstico por imagen , Médula Espinal/patologíaRESUMEN
Plantar pressure-measurement technology is being increasingly used by podiatric physicians and surgeons in both clinical practice and research. The authors present normal reference-range values for peak pressure, mean pressure, and pressure-time integral obtained from 30 healthy subjects using a two-step recording technique and the EMED-SF system, as background for proposed clinical trials. Normative data of this type are essential for clinical practice in the comparison of plantar pressure-measurement values of individual patients with those of normal, asymptomatic feet.
Asunto(s)
Pie/fisiología , Podiatría/instrumentación , Proyectos de Investigación , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Presión , Valores de ReferenciaRESUMEN
Plantar pressure-measurement technology may provide the clinician with valuable objective information for monitoring the effects of therapeutic intervention on the foot. The use of this technology is described in the preoperative and postoperative assessment of a patient undergoing hallux valgus surgery for the treatment of a chronic neuropathic skin ulcer over the medioplantar aspect of her first metatarsophalangeal joint.
Asunto(s)
Úlcera del Pie/fisiopatología , Úlcera del Pie/cirugía , Pie/fisiopatología , Hallux Valgus/cirugía , Anciano , Enfermedad Crónica , Femenino , Úlcera del Pie/etiología , Hallux Valgus/fisiopatología , Humanos , Enfermedad Iatrogénica , Huesos Metatarsianos/fisiopatología , Métodos , Enfermedades del Sistema Nervioso Periférico/complicaciones , Presión , Proyectos de Investigación , Trastornos de la Sensación/complicaciones , Soporte de PesoRESUMEN
This study compared preoperative and postoperative results for selected radiographic measurements of 30 patients undergoing the modified Austin bunionectomy procedure for the correction of hallux abducto valgus. Significant reductions in all postoperative radiographic values were demonstrated, including hallux abductus angle, metatarsus primus adductus angle, tibial sesamoid position, and first metatarsal protrusion distance.