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  • Author or Editor: A. Méndez x
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A stability-indicating liquid chromatographic (LC) method with UV detection was developed for the determination of doripenem in the marketed formulation (Doribax® 500 mg, powder for injection). A forced degradation study was conducted according to available guidelines and main references. Thermal, oxidizing, acidic and basic stress conditions were assayed to show the stability-indicating power of the method. Chromatographic separation was achieved using an isocratic elution method in a reversed-phase system using a mobile phase prepared from phosphate buffer and acetonitrile. Extensive degradation was observed under thermal, oxidative and basic treatment, and the products formed were detected without interference in the analysis of doripenem. To verify the efficiency of chromatographic run, the system suitability was studied. The theoretical plates (N = 5498.3) and tailing factor (tf = 0.951) were constant during repeated injections. The retention time of doripenem was 7.35 min and the method was validated within the concentration range 5–50 μg mL−1 (r = 0.999). Adequate results were obtained that indicate repeatability (RSD % = 1.03–1.37), inter-day precision (RSD % = 0.51) and accuracy. In comparison to spectrophotometric and microbiological methods, statistical analysis showed no significant difference between the obtained results. The proposed method was successfully applied to doripenem quantification, showing it is applicable to determine the antibiotic in the presence of degradation products and also that is a reliable method for routine analysis.

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Journal of Behavioral Addictions
Authors: Guilherme Borges, Ricardo Orozco, Corina Benjet, Kalina I. Martínez Martínez, Eunice Vargas Contreras, Ana Lucia Jiménez Pérez, Alvaro Julio Peláez Cedrés, Praxedis Cristina Hernández Uribe, María Anabell Covarrubias Díaz Couder, Raúl A. Gutierrez-Garcia, Guillermo E. Quevedo Chavez, Yesica Albor, Enrique Mendez, Maria Elena Medina-Mora, Philippe Mortier and Hans-Juergen Rumpf

Background and aims

DSM-5 includes Internet gaming disorder (IGD) as a condition for further study. While online and offline gaming may produce undesired negative effects on players, we know little about the nosology of IGD and its prevalence, especially in countries with emerging economies.


A self-administered survey has been employed to estimate prevalence of DSM-5 IGD and study the structure and performance of an instrument in Spanish to measure DSM-5 IGD among 7,022 first-year students in 5 Mexican universities that participated in the University Project for Healthy Students (PUERTAS), part of the World Health Organization’s World Mental Health International College Student Initiative.


The scale for IGD showed unidimensionality with factor loadings between 0.694 and 0.838 and a Cronbach’s α = .816. Items derived from gaming and from substance disorders symptoms mixed together. We found a 12-month prevalence of IGD of 5.2% in the total sample; prevalence was different for males (10.2%) and females (1.2%), but similar for ages 18–19 years (5.0%) and age 20+ (5.8%) years. Among gamers, the prevalence was 8.6%. Students with IGD were more likely to report lifetime psychological or medical treatment [OR = 1.8 (1.4–2.4)] and any severe role impairment [OR = 2.4 (1.7–3.3)]. Adding any severe role impairment to the diagnostic criteria decreased the 12-month prevalence of IGD to 0.7%.

Discussion and conclusions

Prevalence of DSM-5 IGD and the performance of diagnostic criteria in this Mexican sample were within the bounds of what is reported elsewhere. Importantly, about one in every seven students with IGD showed levels of impairment that would qualify them for treatment under DSM-5.

Open access