Presence des résidus de médicaments dans les eaux usees du Centre Hospitalier et Universitaire de Yaounde

Pharmacotoxicology and pharmacokinetic, Yaounde I
June, 2015


Human pharmaceutical residues are fast becoming an environmental concern. Their occurrence has been reported in many countries especially in Europe and America. They have been reported to have eco-, geno- and human toxic effects and thus their importance as micro pollutants cannot be ignored. However, African countries are still lagging behind in research concerning these micro pollutants. In view of this fact, the present study objective was to investigate the presence of pharmaceutical residue in University Hospital Centre of Yaoundé.
We realized an analytical transversal and experimental study for six months. Three months were for a survey within hospital services in order to list drugs found in medical file of patients hospitalized during 2014. We then established a list of drugs consumed and their estimated quantities. Based on that, we selected the most representative ones dealing with the fact that they are the ones supposed to be found in the waste water. At the end we collected 1L sample of CHUY waste water in order to screen the pharmaceuticals based on the list of the most consumed drugs and the standards available. The screening was done through 2 methods: high performance liquid chromatography coupled to a triple quadrupole analyser (LC/QQQ) and high performance coupled to a mass spectrometer with a time of flight analyser (LC/Q-TOF).
The survey permitted to list 176 molecules classified into 23 therapeutics classes. The most represented were antibiotics (37.293 %), antiparasitics (31.315 %), antihypertensive (10.473 %), antacids (9.377 %) and analgesics (7.851 %). Artemether (17.262 %) and artesunate (11.225 %) were the most consumed pharmaceuticals; following by omeprazole (9.230 %), amoxicillin (8,675 %), paracetamol (6.832 %), furosemid (6.205 %), pyrazinamid (4.923 %), levofloxacine (4.039 %), clavulanic acid (3.529 %), ethambutol (3.384 %), sulfamethoxazole (3.170 %), labetolol (2.461 %) and nicardipine (1.567 %). These 13 compounds were the first part of our selected pharmaceuticals. We also include compounds that were already in data basis of the laboratory .
The analysis of sample through liquid chromatography coupled to a mass spectrometer with a triple quadripole analyser (LC/QQQ) which targeted 20 pharmaceuticals permit to identify and quantify 10 pharmaceuticals: paracetamol (211926 ng/L), sucralose (13073 ng/L), caffeine (5800 ng/L), carbamazepine (940 ng/L), atenolol (427 ng/L), diphenhydramine (377 ng/L), trimethoprim (265 ng/L), sulfamethoxazole (162 ng/L) and clarithromycine (88 ng/L). The analysis of sample through LC/Q-TOF in full scan mode permit to identify 9 more pharmaceuticals: metformin (154000 g/L), ibuprofen (141000 ng/L), tramadol O-demethyl (141000 ng/L), tramadol (76000 ng/L), cimetidine (34000 ng/L), ciprofloxacine (24000 ng/L), erytromycine anhydrate (7000 ng/L), omeprazole hydroxyl (5000 ng/L), and azithromycine (390 ng/L); arthemether and artesunate were not detected.
This study is an initiation of data for the occurrence of pharmaceuticals residues in hospital waste water of Cameroon using 2 methods: LC/QQQ and LC/Q-TOF. It is has shown that CHUY waste water constitutes a source of pollution for the environment. The compounds detected and quantified are part of the most used therapeutics classes and so far little study has been done on their occurrence and fate in the environment.
We recommend therefore to put in place a purifying waste water station at CHUY and for all the reference hospitals in Cameroon. Pharmaceutical waste management should be integrated into the strategic development plan of the Ministry of Public Health.