Pharmacokinetic Profile and Comparative Bioavailability of an Oral Fixed-Dose Combination of Metformin and Acetylsalicylic Acid (Aspirin).

Patients with diabetes face a 2-4-fold greater cardiovascular risk compared to those without diabetes. Both metformin and acetylsalicylic acid (aspirin) treatment have demonstrated a significant reduction in this risk. This single-center, open-label, sequence randomized, 2 × 2 crossover, single-dose clinical trial evaluated the pharmacokinetics profile and comparative bioavailability of a novel oral fixed-dose combination (FDC) of metformin/acetylsalicylic acid (500/100 mg tablet) versus the reference mono-drugs administered concomitantly, metformin 500 mg tablet and acetylsalicylic acid 100 mg tablet, in 22 healthy Mexican adult volunteers under fasting conditions. Blood samples were collected predose and at specified intervals across a 24-hour period following administration and were analyzed for metformin and salicylic acid using high-performance liquid chromatography coupled with tandem mass spectrometry. Test products were considered to have comparative bioavailability if confidence intervals of natural log-transformed (maximum plasma drug concentration (Cmax), (area under the plasma drug concentration-time curve form 0 up to last sampling time (AUC0 -t), and (area under the plasma drug concentration-time cruve from 0 up to infinity (AUC0 ∞) data were within the range of 80%-125%. The results obtained from the present clinical study demonstrate the comparative bioavailability of the FDC when compared with the coadministration of reference mono-drugs. There were no adverse events or adverse reactions reported throughout the study.

Comparative Bioavailability of Metformin Hydrochloride Oral Solution Versus Metformin Hydrochloride Tablets in Fasting Mexican Healthy Volunteers.

INTRODUCTION: Metformin tablets may be challenging to swallow not only for those patients with dysphagia but also for children and the elderly. A metformin solution was developed for easier administration and flexible dose adjustment mantained with the same bioavailability of tablets. The objective of this study was to assess the single-dose oral bioavailability of metformin hydrochloride administered as an oral solution (500 mg/5 mL) compared with metformin hydrochloride 500 mg tablets in fasting Mexican healthy volunteers. METHODS: A randomized, single dose, two-period, two-sequence, crossover study design with a 7-day washout interval was conducted. Subjects were randomly assigned to receive a single dose of 500 mg metformin hydrochloride, either as an oral solution (test drug) or as a tablet (reference drug), after 10 h of fasting. Plasma samples (16) were collected over a 16-h period after drug administration. Bioequivalence was declared when the ratio for the 90% confidence intervals (CI) of the difference in the means of the log-transformed area under the concentration-time curve from time 0 to the last observed concentration time (AUC0-t), the area under the concentration-time curve extrapolated to infinite time (AUC0-∞), and the maximum plasma concentration (Cmax) of the two products were within 0.80 and 1.25 interval. Plasma concentrations were analyzed using reverse phase chromatography by tandem mass spectrometry (LC-MS/MS). Safety and tolerability of metformin were also assessed in all subjects. RESULTS: 24 subjects were enrolled and completed the study (15 female and 9 male). Test and reference metformin hydrochloride were bioequivalent during the extent of exposure since AUC0-t and Cmax 90% CIs corresponded to 89.77-101.08% and 89.63-102.48%, respectively, both being within the pre-specified acceptance range criteria (80-125%). There were two adverse events (AE) with the reference formulation that were not related to the study drug. CONCLUSIONS: Bioequivalence in healthy volunteers in fasting conditions of the two metformin hydrochloride formulations (oral solution and tablets) was established, being the difference in means of AUC0-t, AUC0-∞ and Cmax within the acceptance range (80-125%). Oral solution formulation could offer the advantages of allowing adjusted doses and easier swallowing for every patient. Plain language summary is available for this article. TRIAL REGISTRATION: National Clinical Trials Registry (RNEC by its Spanish acronym), BD METF-Sil No. 86-15. Mexican Medicine Agency (COFEPRIS) Registry: 153300410B0368. FUNDING: Laboratorios Silanes, S.A. de C.V.

Confirmación de dexametasona y diclofenaco por LC-MS-MS como adulterantes en un producto herbolario / Dexamethasone and diclofenac by LC-MS-MS as herbal product adulterants

Objetivo. Confirmar la presencia de dexametasona y diclofenaco como adulterantes de un producto comercializado como de origen natural. Material y métodos. Para la identificación y confirmación de la presencia de los fármacos se utilizó un método de análisis instrumental por cromatografía de líquidos de alta presión acoplado a espectrometría de masas en tándem. Resultados. En el análisis de 11 frascos de Reumofan Plus obtenidos de pacientes y médicos de la localidad se confirmó la presencia de dexametasona y diclofenaco. La metodología utilizada permitió separar los esteroisómeros dexametasona y betametasona, las abundancias relativas de iones productos 237.2 y 279.2 m/z permiten diferenciar espectralmente un compuesto de otro. Conclusiones. Se confirmó la presencia de dexametasona y diclofenaco en muestras de un producto comercializado como "100% natural" obtenidas de diferentes pacientes o médicos en el periodo enero a diciembre de 2011.

Objective. To confirm the presence of dexamethasone and diclofenac as adulterants of an herbal product. Materials and methods. For identificaction and confirmation of drugs a method of instrumental analysis by liquid chromatography coupled with high pressure tandem mass spectrometry was used. Results. The presence of dexamethasone and diclofenac was confirmed in samples of 11 bottles of Reumofan Plus obtained from patients and/or physicians. The methodology used, allowed separation of stereoisomers dexamethasone and betamethasone, the relative abundances of product ions 237.2 and 279.2 m / z spectrally differentiate the compounds. Conclusions. The presence of dexamethasone and diclofenac was confirmed in samples of a product marketed as "100% natural" obtained from patients and / or physicians in a period from January to December, 2011.

[Dexamethasone and diclofenac by LC-MS-MS as herbal product adulterants]. / Confirmación de dexametasona y diclofenaco por LC-MS-MS como adulterantes en un producto herbolario.

OBJECTIVE: To confirm the presence of dexamethasone and diclofenac as adulterants of an herbal product. MATERIALS AND METHODS: For identificaction and confirmation of drugs a method of instrumental analysis by liquid chromatography coupled with high pressure tandem mass spectrometry was used. RESULTS: The presence of dexamethasone and diclofenac was confirmed in samples of 11 bottles of Reumofan Plus obtained from patients and/or physicians. The methodology used, allowed separation of stereoisomers dexamethasone and betamethasone, the relative abundances of product ions 237.2 and 279.2 m / z spectrally differentiate the compounds. CONCLUSIONS: The presence of dexamethasone and diclofenac was confirmed in samples of a product marketed as "100% natural" obtained from patients and / or physicians in a period from January to December, 2011.

Temporal analysis of PM10 in Metropolitan Monterrey, México.

The Monterrey Metropolitan Area (MMA) is the third largest city in Mexico. Few studies have been carried out regarding its air pollution. The aim of this study was to analyze the temporal behavior of PM10 (particulate matter < or =10 microm in aerodynamic diameter). Data reported by the "Sistema Integral de Monitoreo Ambiental" (Integrated Environmental Monitoring System) network from 2006 to 2008 were used. PM10 levels were compared among the stations by year, season, and day of week. A bootstrap technique was used to obtain subsamples to which Student's t test and ANOVA were applied. PM10 levels were high and exceeded the annual limit of 50 microg/m3 set up by the Mexican standard Norma Oficial Mexicana NOM-025-SSA1-1993. These levels could have serious health effects. The southwest zone of MMA had the highest levels of PM10 during the period studied. Winter was the most polluted season, and summer was the least polluted season. Thursday and Friday were the most polluted days, and Sunday was the least polluted day. The hours with the highest levels of PM10 were 8:00 to 10:00 a.m., whereas nighttime hours were the cleanest.