Validation of three analytical methods for quantification of acetaminophen by UV spectrophotometry

Introduction: Acetaminophen is a non-steroidal analgesic and antipyretic, whose mechanism is based on the inhibition of the cyclooxygenase enzyme responsible for the appearance of pain and inflammation. In Mexico, it is one of the drugs widely used for its effectiveness, which is why the objective of this study was to implement a method of chemical validation by ultraviolet spectrophotometry that allows the quantification of this active principle. Method: We worked with 4 dissolution media (HCl: 0.1N MeOH, 0.1M HCl, Methanol: Water in a ratio of 15:85 p / v and 0.2M phosphate buffer). All four media underwent analytical validation, measuring linear regression significance, precision, sample stability, and sensitivity. Results:The 0.1M HCl, MeOH: H2O (15:85 v / v) and Phosphate Buffer media comply with the significance of the intercept, linearity of the method, as well as the parameters of precision, stability, and with the limits of detection (DL) and the limit of quantification (QL). Discarding the HCl: 0.1N MeOH medium for not meeting the linearity parameters. Conclusions: Of the fourth means evaluated, three of them (0.1M HCl, Methanol: water, and phosphate buffer) can be used as alternatives in the quantification of this drug (AU)

Introducción: El acetaminofén es un analgésico y antipirético no esteroideo, cuyo mecanismo se basa en la inhibición de la enzima ciclooxigenasa responsable de la aparición de dolor e inflamación. En México es uno de los fármacos ampliamente usados por su efectividad, es por ello, el objetivo de este estudio fue implementar un método de validación química por espectrofotometría ultravioleta que permita la cuantificación de este principio activo. Método: Se trabajó con 4 medios de disolución (HCl:MetOH 0,1N, HCl 0,1M, Metanol: Agua en proporción 15:85 p/v y solución amortiguadora de fosfatos 0,2M). Los cuatro medios se sometieron a una validación analítica, midiendo Significancia de la regresión lineal, precisión, estabilidad de la muestra y sensibilidad.Resultados:Los medios HCl 0,1M, MetOH:H2O (15:85 v/v) y Buffer de fosfatos cumplen con la significancia del intercepto, linealidad del método, así como los parámetros de precisión, estabilidad y con los límites de detección (DL) y el límite de cuantificación (QL). Descartando el medio de HCl: MetOH 0,1N por no cumplir con los parámetros de linealidad. Conclusiones: De los cuatro medios evaluados tres de ellos (HCl 0,1M, Metanol: agua y amortiguador de fosfatos) se pueden usar como alternativas en la cuantificación de este fármaco (AU)

Trends in Microbiological and Antibiotic Sensitivity Patterns in Infectious Keratitis: 10-Year Experience in Mexico City.

PURPOSE: To report the distribution and trends in microbiological and antibiotic sensitivity patterns of infectious keratitis in a 10-year period at a reference center in Mexico City. METHODS: In this retrospective observational case series, samples were obtained from corneas with a diagnosis of infectious keratitis from January 2002 to December 2011 at the Institute of Ophthalmology "Conde de Valenciana" in Mexico City. Results of cultures, stains, and specific sensitivity/resistance antibiograms for each microorganism were analyzed. RESULTS: A total of 1638 consecutive corneal scrapings were analyzed. Pathogen was recovered in 616 samples (38%), with bacterial keratitis accounting for 544 of the positive cultures (88%). A nonsignificant increasing trend in gram-negative isolates (P = 0.11) was observed. The most commonly isolated pathogen was Staphylococcus epidermidis, and the most common gram-negative isolated species was Pseudomonas aeruginosa. Methicillin-resistant Staphylococcus aureus (MRSA) was present in 45% of the S. aureus isolates; meanwhile, 53.7% coagulase-negative Staphylococcus isolates were methicillin resistant (MRCNS). Pseudomonas aeruginosa resistance to ceftazidime increased from 15% in the first period to 74% for the last 5 years of the study (P = 0.01). The overall sensitivity for vancomycin of MRSA was 87.5%, whereas 99.6% of the MRCNS were sensitive. CONCLUSIONS: There was a nonsignificant increase in the recovered gram-positive and gram-negative microorganisms over time. We observed an increased resistance to methicillin in almost half of the MRSA and MRCNS isolates.