Tese
Identificação e determinação de fármacos ansiolíticos e antiepilépticos e seus metabólitos em efluente hospitalar
Fecha
2012-12-06Registro en:
ALMEIDA, Carlos Alberto Araujo de. Identification and determination of metabolites of antiepileptic and anxiolytic drugs in hospital effluent. 2012. 167 f. Tese (Doutorado em Química) - Universidade Federal de Santa Maria, Santa Maria, 2012.
Autor
Almeida, Carlos Alberto Araujo de
Institución
Resumen
A new analytical methodology was developed in order to investigate the presence of five psychoactive
drugs (anxiolytic and antiepileptics), namely, bromazepam, carbamazepine, clonazepam, diazepam, and
lorazepam in the effluent of the University Hospital of Santa Maria (HUSM) of the Federal University of
Santa Maria (UFSM), since these compounds are widely used in the treatment of anxiety and epilepsy.
Samples were collected from two points to check the concentration of the compounds: Point A
(Emergency) and point B (General Effluent - which covers the Central Library and HUSM). The method of
clean-up/pre-concentration by solid phase extraction (SPE) was used to assess the occurrence of
anxiolytic and antiepileptic drugs in the effluent of HUSM. Three methods were developed and validated to
determine these compounds: i) high performance liquid chromatography with ultraviolet detection (HPLCUV),
ii) high performance liquid chromatography with detection by mass spectrometry (LC-MS), and iii)
liquid chromatography-ion trap-tandem mass spectrometry with electrospray ionization (LCMS/
MS_Qtrap). Among the methods evaluated, LC-MS/MS_Qtrap with electrospray in positive mode
yielded better results. The detection limit (LOD, S/N ≥3) for lorazepam and bromazepam was 4.90±0.95 ng
L-1 and for carbamazepine, clonazepam and diazepam, 6.10±1.50 ng L-1. The limit of quantification (LOQ,
S/N ≥10) was 30.00±1.10 ng L-1 bromazepam , clonazepam and lorazepam; 50.00±1.81 ng L-1,
carbamazepine; and 40.00±0.98 ng L-1 diazepam. The linear range of the assay (LC-MS/MS_Qtrap) was
30-1500 ng L-1 for bromazepam; 50-2500 ng L-1, carbamazepine; 30-2500 ng L-1, clonazepam; 40-2500
ng L-1, diazepam; and 30 - 2000 ng L-1, lorazepam. The correlation coefficient (R2>0.997) for all
compounds. The effectiveness of the methodology was verified by recovery with the fortification of three
concentration levels in triplicate samples of hospital effluent. The average recovery rates observed were:
93.9±2.1% for bromazepam; 92.6±4.2%, carbamazepine; 93.9%±3.0 clonazepam; 91.8%±6.0 for
diazepam; and 93.8%±4.3 for lorazepam. The mean concentrations of psychiatric drugs detected in the
effluent of the Emergency and General Effluent were respectively: 195.0±6.4 ng L-1 and 137.1±7.0 ng L-1
for bromazepam; 589.6±6.1 ng L-1, and 460.7±9.3 ng L-1, carbamazepine; 645.0±0.3 ng L-1 and 571.0±
9.9ng L-1, diazepam; 95.7±6.7 ng L-1 and 42.4±4.2 ng L-1 lorazepam; and 134.3 ± 9.8 ng L-1 and 56.9 ±
9.9 ng L-1 clonazepam. The identification of metabolites in the hospital effluent was made through (LCMS/
MS_Qtrap). The metabolites identified were: 3-hydroxybromazepam (bromazepam), 7-
aminoclonazepam (clonazepam), carbamazepine 10,11-epoxide, 10-dihydroxy-10,11-
dihydrocarbamazepine, iminoquinone, 2-hydroxy-carbamazepine and acridone (carbamazepine), and
nordiazepam, oxazepam and temazepam (diazepam), and their fragmentation pathways were proposed.
Was performed a preliminary risk assessment of anxiolytic and antiepileptic drugs with the aid of literature
data and found that the carbamazepine and diazepam compounds showed the highest risk (0.85 and 0.90,
respectively) among the compounds analyzed. According to the results we can say that they present
medium risk requiring more attention in terms of toxicity. However, no literature data were found on the
Predicted No Effect Concentration (PNEC) for bromazepam, lorazepam, clonazepam, not allowing the
calculation of risk quotient (RQ) for these compounds.Therefore, we observed the occurrence of anxiolytic
and antiepileptic drugs in the effluent of HUSM at concentrations in the order of ng L-1. The analytical
method for LC-MS/MS_Qtrap developed for the determination of psychoactive drugs (bromazepam,
carbamazepine, clonazepam, diazepam and lorazepam) in hospital effluent proved to be sensitive and
selective, eliminating laborious sample handling and requiring chromatographic run of just 15 minutes. The
occurrence of these drugs and environmental risks associated demonstrate the need for more efficient
treatment for the hospital effluent.