Class of 2013 Abstract / Specific Aims: The purpose of this study was to retrospectively evaluate sulfamethoxazole concentrations obtained in adult patients with varying degrees of renal function. The first study aim was to identify sulfamethoxazole serum concentrations obtained from patients who received high-dose trimethoprim/sulfamethoxazole. The second aim is to examine the relationship between sulfamethoxazole concentrations, trimethoprim/sulfamethoxazole doses prescribed, and subjects' estimated renal function. Methods: This institutional review board approved study examined sulfamethoxazole serum concentrations in adult patients with varying renal function. Subjects selected had recorded sulfamethoxazole blood concentrations while receiving high-dose sulfamethoxazole/trimethoprim between June 2006 and May 2012 while admitted to an academic medical center. For the first study aim, patients were grouped by renal function with estimated creatinine clearance exceeding 30 ml/min, creatinine clearance of 15 to 30 ml/min, and creatinine clearance of less than 15 ml/min. For the last group, dosing practices were described since few recommendations for this degree of renal function exist. For the first two groups, adherence to literature recommendations was evaluated. The second aim was addressed with a population pharmacokinetic analysis. A one compartment model was used with first-order elimination. Oral dosing was incorporate a separate administration compartment with first order transfer to compartment 1. Intravenous dosing was handled as a rate input into compartment 1. For patients with estimated creatinine clearance greater than 60 ml/min, all doses within the prior 48 hours were entered while those with estimated creatinine clearance less than 60 ml/min only the prior 96 hours of doses before a concentration were entered. Sulfamethoxazole concentrations were assessed in context of trimethoprim/sulfamethoxazole dose and renal function. Main Results: A total of 77 subjects who had a total of 206 sulfamethoxazole concentration(s) obtained while receiving high-dose sulfamethoxazole/trimethoprim. The sulfamethoxazole concentrations ranged from undetectable to 316.8 mcg/mL with a median value of 79.6 mcg/mL. The number of sulfamethoxazole concentrations obtained per subject ranged from 1 to 8 concentrations. The pharmacokinetic analysis of these sulfamethoxazole concentrations based on subjects’ estimated renal function and doses prescribed is in progress. Conclusion: To be determined.

Many studies have demonstrated that sewage treatment plants do not efficiently degrade pharmaceuticals such as antibiotics, hormones, and analgesics. Ozonation has been identified as a promising technique to degrade those compounds. A series of experiments was used to evaluate the impact of three parameters on the efficiency and kinetics of degradation of sulfamethoxazole, an antibiotic, by ozonation. An ozone reactor was designed to perform experiments. Analytical techniques, based on liquid and gas chromatography and mass spectrometry, were developed to measure concentrations of sulfamethoxazole and identify degradation products. / It was shown that the rate constant and the degradation efficiency are greater when the initial concentration of sulfamethoxazole is lower; the presence of other contaminants in solution decreases the percentage of degradation observed, and the concentration of hydrogen peroxide, used as catalyst, must be well adjusted since an inappropriate concentration hinders the reaction. Finally, the analysis of ozonated samples allowed the identification of degradation products and resulted in a proposed degradation mechanism.

No description available.

Utilizing the in vitro human placental model, we studied the placental transfer of trimethoprim and sulfamethoxazole. At trimethoprim concentrations of 7.2 μg/ml, only 1.4 μg/ml was transported across the placenta after 1 h, and at concentrations of 1.0 μg/ml, one half the usual serum level, only 0.08 μg/ml was transported across the placenta. Maternal concentrations of sulfamethoxazole of 29.6 and 127.7 μg/ml resulted in concentrations of 5.1 and 14.8 pg/ml on the fetal side, respectively. Thus, it would appear that trimethoprim is slowly transported across the placenta and in low concentrations whereas sulfamethoxazole readily crosses the placenta. The combination of these drugs is useful for treatment of bacteriuria. It may also prove to be especially useful for Pneumocystis carinii infections in pregnant women with AIDS. With a half-life of 13 h for trimethoprim and 6 h for sulfamethoxazole, the drugs are not likely to achieve toxic levels in the fetal compartment. Thus, it would appear that trimethoprim and sulfamethoxazole may be both efficacious and safe for the treatment of both these infections during pregnancy.

Thesis (M.S.)--University of Florida, 2004. / Typescript. Title from title page of source document. Document formatted into pages; contains 186 pages. Includes Vita. Includes bibliographical references.

De nos jours, l'émergence de produits pharmaceutiques dans l'environnement aquatique et terrestre a été une préoccupation majeure. Ils ont été détectés dans les stations d'épuration, les sédiments et les sols ainsi qu'à la surface et dans l'eau potable. Jusqu'à présent, il y a peu d'informations dans la littérature sur le devenir de ces composés lorsqu'ils sont exposés à la lumière solaire dans les différents compartiments environnementaux. Dans le cadre de ce travail, notre objectif est l’étude de comportement des antibiotiques de la famille des Sulfonamides : Sulfaméthoxazole (STZ), Sulfathiazole (STL), Sulfamethazine (STN) et Hydrochlorothiazide (HCD) dans des solutions aqueuses lorsqu'ils sont exposés à la lumière solaire. Nous nous sommes principalement intéressés à l’étude cinétique en évaluant le rendement quantique de dégradation ainsi que l'effet de divers paramètres tels que la concentration en oxygène, le pH et la présence d'ions inorganiques. Nous nous sommes également intéressés à l'élucidation des principaux sous-produits intermédiaires. De nombreuses informations sont disponibles sur la stabilité et le devenir des composés d'origine et beaucoup moins sur leurs produits de transformation. Ces derniers peuvent présenter un niveau de toxicité plus élevé que le substrat précurseur et doivent ainsi être identifiés et analysés. L'élucidation de la structure a été obtenue en utilisant les techniques HPLC / ESI / MS et HPLC / ESI / MS2 en modes négatif et positif et par l'étude complète des différentes voies de fragmentation. Les principaux processus photochimiques impliqués sont : i) la scission du pont par photohydrolyse, ii) l'hydroxylation sélective de la partie aromatique iii) le processus de désulfonation et iiii) dans le cas de HCD une réaction de déchloration. Un mécanisme photochimique a été proposé sur la base des études cinétiques et analytiques. / Nowaday the emergence of pharmaceuticals in the aquatic and terrestrial environment have been a major concern. They have been detected in sewage-treatment plants, sediments, and soils as well as at surface and drinking water. So far, there is limited information in the literature on the fate of these compounds once they are exposed to solar light in the various environmental compartments. In the present work we have been interested in studying the behavior of antibiotics from Sulfonamide family: Sulfamethoxazole (STZ), Sulfathiazole (STL), Sulfamethazine (STN) and Hydrochlorothiazide (HCD) in aqueous solutions upon exposure to simulated solar light. We mainly concentrate our effort on the kinetic studies by evaluating the degradation quantum yield as well as the effect of various parameters such as oxygen concentration, pH and the presence of inorganic ions. The main effect was observed by molecular oxygen parameter. We also make an important effort in the elucidation of the main intermediate and stable by-products. A lot of information is available on the stability and fate of parent compounds and not so many on their transformation products. These may present a toxicity level higher than the precursor substrate and should be identified and analysed. The chemical structure elucidation was obtained by using the HPLC/ESI/MS and HPLC/ESI/MS2 techniques in negative as well as positive modes and through the complete study of the various fragmentation pathways. The main involved photochemical processes were identified as i) the scission of the bridge through a photohydrolysis process, ii) selective hydroxylation of the aromatic moiety iii) Desulfonation process and iiii) in the case of HCD to dechloration reaction. A mechanism was then proposed in the light of the kinetics and analytical studies.

The drug-drug interaction involving zidovudine and sulfamethoxazole-trimethoprim was investigated using an in vitro culture system, an in vivo mouse model, and a clinical trial in HIV-infected patients. We hypothesized that combination exposure causes immune cell populations in the bone marrow to undergo apoptotic cell death, and that the toxicity would affect the host response to an infectious stimulus. Mice were dosed with zidovudine, sulfamethoxazole-trimethoprim, the combination of both drugs, or vehicle only control via oral gavage. Focusing on B-lineage cells in the bone marrow, we determined that cells of the rapidly cycling, early pre-B cell subset are targeted, as well as pro-B cells earlier in development. This toxicity was found to be cell cycle dependent, with an increase in percentage of cells in the S/G2/M phases of the cycle. In vitro experiments using the drugs in a bone marrow culture system demonstrated that the effect of cytotoxicity with combination exposure is synergistic and concentration-dependent. The mechanism of apoptosis that is induced appears to be caspase-independent. To measure host response in mice, animals treated with zidovudine plus sulfamethoxazole-trimethoprim were infected with Pneumocystis murina pneumonia, and the group that received the combination of agents had a blunted antigen-specific IgG response, possibly due to a decreased number of B cells and activated B cells in the draining lymph nodes of the lungs. A clinical trial was conducted in HIV-infected patients, dividing subjects into groups receiving zidovudine, sulfamethoxazole-trimethoprim, the combination of both, or neither agent. Upon vaccination with the influenza vaccine, the combination treatment group had a blunted humoral response, with reduced antigen-specific serum IgG titers as compared to the control group. We conclude that the drug-drug interaction involving zidovudine and sulfamethoxazole-trimethoprim is clinically-significant, and clinicians must consider this toxicity when treating patients with these agents concurrently.

The wide use and the incomplete metabolism of antibiotics, along with the poor removal efficiency of current treatment systems, results in the introduction of large quantities of antibiotics to the environment through the discharge of treated and untreated wastewater. If not treated or attenuated near the source of discharge, the antibiotics can be distributed widely in the environment. In this research, sulfamethoxazole (SMX), a common sulfonamide antibiotic, was selected as a model compound due to its presence in the environment and its resistance to remediation and natural attenuation. Among the various entry routes, discharges from on-site disposal systems are of particular interest due to the wide use of these systems. The complex nature of subsurface transport downstream of these systems adds difficulties to the removal of SMX from subsurface discharges. For this research, two processes that impact SMX removal, biodegradation and sorption, were examined to determine the primary factors governing the elimination of SMX from septic effluent discharges in the subsurface. To characterize the biodegradation of SMX, batch experiments were conducted with SMX in the presence of septic effluent and soil for both aerobic and anoxic conditions. Results showed that SMX removal was limited in the septic effluent but increased in the presence of soil, demonstrating the important role of the soil in SMX removal in both aerobic and anoxic conditions. Addition of external nutrients (ammonium and sulfate) had small effects on SMX removal, although SMX removal was enhanced under aerobic condition with increased dissolved organic carbon. To overcome the limited sorption of SMX on soil, soil amendments were developed and evaluated using biochar, a green and cost-effective adsorbent. Biochars produced from different types of feedstock were characterized for different pyrolysis temperatures, and their adsorption behaviors were examined and compared with commercial biochar and activated carbon (AC). Adsorption isotherms were developed and adsorption kinetics of soil, biochar and AC were studied. Results showed that adsorption on soil, biochar and AC followed three different kinetics models and their equilibrium isotherms followed the Freunlich model. Higher adsorption rates were achieved with biochars prepared at the higher temperature. A lab-engineered biochar with pine sawdust at 500 °C achieved comparable sorption capacity to AC. SMX transport in subsurface was also explored with saturated soil columns filled with soil that was mixed with biochar at different percentages. Significant SMX removal (including complete elimination at a low flowrate and over 90 % elimination at a high flowrate) for all cases was primarily attributed to biodegradation. These results provide insight into the transport and transformations affecting SMX, and then provide a basis for developing low-cost approaches for the mitigation of SMX.

A ocorrência de produtos farmacêuticos e de cuidados pessoais no meio ambiente tem levado a preocupações sobre seu impacto ambiental e à saúde pública. O sulfametoxazol (SMX) é um fármaco que tem sido encontrado amplamente no ambiente. Neste estudo foi verificada a eficácia de vários processos, a saber eletroquímico, eletroquímico foto assistido, fotoquímico, Fenton e foto-Fenton, para a degradação de SMX em solução aquosa. A degradação eletroquímica e eletroquímica foto assistida foram realizadas em uma célula de fluxo do tipo filtro-prensa, usando um ânodo dimensionalmente estável comercial com composição nominal Ti/Ru0,3Ti0,7O2. Durante ambos os processos, efeitos de diferentes parâmetros foram analisados, como a natureza do eletrólito, a concentração de eletrólito suporte (NaCl) e a densidade de corrente aplicada. Os experimentos fotoquímicos, Fenton e foto-Fenton foram realizados em um reator de vidro cilíndrico de compartimento único. O efeito das concentrações inicias de Fe2+ e de H2O2 foram estudados para os processos Fenton e foto-Fenton. Similarmente, o efeito do pH inicial, a concentração inicial do SMX e a temperatura foram investigados para todos os processos. A variação da concentração de SMX foi determinada por cromatografia líquida de alta eficiência (CLAE) e a quantidade de matéria orgânica foi monitorada por análise de carbono orgânico total (COT). Os resultados obtidos indicaram que o SMX foi completamente degradado, porém, o COT foi apenas parcialmente removido em todos os processos. No período de tempo de ensaio estabelecido o aumento da densidade de corrente e da concentração de NaCl mais eficiente para a degradação e remoção de COT nos processos eletroquímicos. A quantidade de Fe2+ e H2O2 aumenta a eficiência do processo Fenton e foto-Fenton, e meio ácido foi favorável para todos os processos. O consumo de energia elétrica, baseado no parâmetro EEO (energia por ordem) mostrou que os processos eletroquímicos são energeticamente mais eficientes do que os fotoquímicos. As degradações acompanhadas por CLAE acoplado à espectrometria de massas, permitiu que vários intermediários fossem identificados, sendo então proposta uma sequência reacional para a degradação do SMX. O radical hidroxila e o cloro ativo atacam os anéis benzílico e isoxazólico, tendo sido demonstrado que os compostos iniciais formados foram os compostos hidrolisados e clorados. Os íons inorgânicos, tais como: NO3-, NH4+ e SO42-, também foram identificados durante os processos de degradação. / The occurrence of pharmaceuticals and personal care products in the environment has raised concerns about their impact upon environmental and public health. Sulfamethoxazole (SMX) is a pharmaceutical that has been found widely in the environment. This study investigated the effectiveness of various processes such as electrochemical, photo assisted electrochemical, photochemical, Fenton photo-Fenton to SMX degradation in aqueous solution. The electrochemical and photo-assisted electrochemical degradations were performed in a filter press type flow cell using a dimensionally stable anode with nominal composition of Ti/Ru0.3Ti0.7O2. During both these processes the effects of different parameters were analyzed, such as, nature of the electrolyte concentration of the supporting electrolyte (NaCl) and the applied current density. The photochemical, Fenton and photo - Fenton experiments were carried out in a single compartment cylindrical glass reactor. The effects initial iron concentrations and H2O2 were studied for Fenton and photo-Fenton processes. Similarly the effect of initial pH, initial concentration of SMX and temperature were investigated for all processes. The variation of SMX concentration was determined by high performance liquid chromatography (HPLC) and the amount of organic matter was monitored by analysis of total organic carbon (TOC). The results indicated that SMX was completely degraded, but TOC was partially removed in all processes studied, during experimental period the increase of the current density and NaCl concentration enhanced the degradation and TOC removal in the electrochemical processes. The amount of iron and H2O2 increases the efficiency of Fenton and photo-Fenton processes and acidic media was favorable for all processes. The electrical energy consumption parameter based on EEO (energy per order) was also evaluated and it was observed that the electrochemical processes are more energetically efficient than the photochemical. The degradations followed by HPLC coupled with mass spectrometry, in which several intermediates were identified and proposed a reaction sequence for the degradation of SMX. The hydroxyl radical and active chlorine attack benzene and isoxazólico rings, and has been demonstrated that the initial compounds formed were hydrolyzed and chlorinated compounds. Inorganic ions such NO3-, NH4+ and SO42- were also identified during degradation processes.

Η μελέτη της τάσης να παραμένουν αναλλοίωτες και της επίδρασης των φαρμακευτικών ουσιών στο περιβάλλον παρουσιάζει τα τελευταία έτη αυξανόμενο ενδιαφέρον. Οι φαρμακευτικές ουσίες που χρησιμοποιούνται από τον άνθρωπο καθώς και οι μεταβολίτες τους, καταλήγουν στις μονάδες βιολογικού καθαρισμού μέσω των λυμάτων των μονάδων παραγωγής τους, των νοσοκομείων, καθώς και των αστικών λυμάτων. Η πιθανή κατάληξη των ουσιών αυτών, εφόσον τα λύματα τυγχάνουν βιολογικής επεξεργασίας, όπως συμβαίνει άλλωστε με όλες τις ξενοβιοτικές ουσίες, μπορεί να εμπίπτει σε μια από τις ακόλουθες περιπτώσεις: • Οι φαρμακευτικές ουσίες ή μεταβολίτες τους βιοαποδομούνται. • Οι φαρμακευτικές ουσίες ή οι μεταβολίτες τους είναι ανθεκτικές ενώσεις στη βιοπαδόμηση και ανάλογα με την υδροφοβικότητά τους, προσροφούνται στην ιλύ ή παραμένουν στην υδατική φάση. Οι ουσίες που δεν προσροφούνται στην ιλύ διέρχονται ανέπαφες μέσα από τις μονάδες βιολογικού καθαρισμού και καταλήγουν στα υδάτινα συστήματα. • Οι φαρμακευτικές ουσίες στην περίπτωση που παραμένουν προσροφημένες στην ιλύ, εάν η ιλύς χρησιμοποιηθεί ως εδαφοβελτιωτικό, μπορούν να διασκορπιστούν στους αγρούς κατά την εφαρμογή της ιλύος και να ρυπαίνουν το έδαφος. Οι ουσίες δε που εμφανίζουν κινητικότητα μπορεί να καταλήξουν στα υπόγεια νερά ή στα επιφανειακά ύδατα. Οι λοιπές δεσμεύονται στο έδαφος. Τα περισσότερα φάρμακα σχεδιάζονται να είναι ανθεκτικά ώστε, αφ’ ενός μεν να διατηρούν τη χημική τους ακεραιότητα προκειμένου να επιτελέσουν το θεραπευτικό τους σκοπό, αφ’ ετέρου δε να έχουν βιολογική δράση. Με δεδομένη την ανθεκτικότητά τους, η συνεχής εκπομπή τους στο περιβάλλον έχει ως αποτέλεσμα την παρουσία τους για σημαντικό χρονικό διάστημα, προξενώντας πιθανότατα σοβαρές αρνητικές επιπτώσεις τόσο στα υδάτινα όσο και εδαφικά οικοσυστήματα. Η άμεση ή έμμεση επαναχρησιμοποίηση των υδάτων έχει ως αποτέλεσμα τη συσσώρευση των ανθεκτικών αυτών ουσιών σε μεγαλύτερες ακόμη συγκεντρώσεις. Στην παρούσα εργασία εξετάζονται έξι φαρμακευτικές ουσίες (προπρανολόλη, διχλωφενακικό νάτριο, σουλφαμεθοξαζόλη, χλωφιβρικό οξύ, καρμπαμαζεπίνη, οφλοξακίνη), οι οποίες έχουν βρεθεί στις εκροές των μονάδων βιολογικού καθαρισμού (Γαλλία, Ελλάδα, Ιταλία, Σουηδία κ.α.) σε συγκεντρώσεις της τάξεως των μικρογραμμαρίων ανά λίτρο. Ερευνήθηκε η τύχη τους σε όλες τις πιθανές διαδρομές που μπορεί να ακολουθήσουν μετά την διάθεσή τους στο αποχετευτικό σύστημα: σύστημα ενεργού ιλύος, θάλασσα, νερό πηγής και έδαφος. Μελετήθηκε δηλαδή η βιοαποδοσιμότητα τους κατά την διεργασία της ενεργού ιλύος και κατά την παρουσία τους σε υδάτινους αποδέκτες. Επίσης, εξετάστηκε η ικανότητά προσρόφησής τους και η κινητικότητα τους σε δύο διαφορετικούς τύπους εδάφους καθώς επίσης και στην αερόβια και αναερόβια ιλύ. Οι φαρμακευτικές ουσίες, με εξαίρεση την σουλφαμεθοξαζόλη, βρέθηκαν να είναι ιδιαίτερα ανθεκτικές στα υδάτινα συστήματα κατά την επεξεργασία τους με διεργασία ενεργού ιλύος. Η αποδόμηση της σουλφαμεθοξαζόλης επιτεύχθηκε κάτω από αερόβιες συνθήκες με τη βοήθεια μιας μεικτής εγκλιματισμένης καλλιέργειας μικροοργανισμών, η οποία και αποτελούσε πηγή άνθρακα ή/και πηγή αζώτου. Κάτι τέτοιο συμβαίνει όταν υπάρχει έλλειψη εναλλακτικής πηγής άνθρακα ή αζώτου. Όσον αφορά στην προσρόφηση των ουσιών στο έδαφος και στην ιλύ, οι συντελεστές προσρόφησης που προσδιορίστηκαν ποικίλουν ανάλογα με τη φύση της ουσίας και του στερεού υλικού (υποστρώματος). Η οφλοξακίνη ήταν ισχυρά προσροφούμενο (με εξαίρεση την περίπτωση της αναερόβιας λάσπης), ενώ το χλωφιβρικό οξύ βρέθηκε ότι είναι το ασθενέστερα προσροφούμενο και ότι εμφανίζει ιδιαίτερη κινητικότητα. Επίσης, η προσρόφηση των ουσιών αποδείχτηκε ότι εξαρτάται σημαντικά από το pH του συστήματος και από την ιοντική ισχύ. Τέλος, η τύχη των φαρμακευτικών ουσιών στο έδαφος προσδιορίστηκε με τη βοήθεια λυσιμέτρων. Οι παράμετροι που εξετάστηκαν ήταν: α) ο ρυθμός φόρτισης των φαρμακευτικών ουσιών β) υδραυλική φόρτιση και γ) η επίδραση της «βροχής». Σημαντικές διαφορές παρατηρήθηκαν στην κινητικότητα των έξι φαρμακευτικών ουσιών, που σχετίζονταν με την ικανότητα προσρόφησης/εκρόφησης των ουσιών, την ποσότητα της ουσίας που εφαρμοζόταν, τη ροή και την ένταση των γεγονότων της «βροχής». / The study of the effect of pharmaceutical substances, as well as their persistence in the environment, has received an increasing interest in the recent years. Pharmaceutical substances used by humans, as well as their metabolites, enter the Sewage Treatment Plants (STP’s) through discharges from production facilities, hospitals and private household effluents. The most likely fate of these substances, provided that the sewages undergo (like all xenobiotic substances) biological treatment, may be one of the following: • The pharmaceutical substances or their metabolites are mineralized by microorganisms to carbon dioxide and water. • The pharmaceutical substances or their metabolites are more or less persistent in the STP, which implies that depending on their lipophilicity, the substances will be partly retained in the sludge or they will remain dissolved in the aquatic phase. The substances that will neither be retained, nor degraded in the STP, easily reach the aquatic systems. • The pharmaceutical substances, in case they are adsorbed on the sludge, if the sludge is used as a soil amendment, may be dispersed on agricultural land. The substances that are mobile in the soil may reach the ground water or leach to a nearby stream. The rest will be retained by soil. Most drugs are designed to be resistant and to maintain their chemical structure, as well as their biological activity, so that they can perform their therapeutic task. All of these factors, together with their continuous discharge, cause them to remain in the environment for significantly extended times, with adverse effects on the aquatic and terrestrial ecosystems. Direct or indirect water reuse leads to accumulation of pharmaceuticals to concentrations much higher than those of the original discharge. In the present work six pharmaceutical substances (propranolol, diclofenac, sulfamethoxazole, clofibric acid, carbamazepine, ofloxacin), which have been found in the effluents of STP’s (France, Greece, Italy, Sweden) in concentrations of the order of micrograms per litter, were examined. Their fate, in all the likely paths that can follow during their disposal in the drainage, such as the process of activated sludge, seawater, fresh water and soil, was studied. The biodegradation of the aforementioned substances was studied during the process of activated sludge as well as when discharged in aquatic (sea and brackish water) receivers. The adsorption capacity and the mobility in two different types of soil, and in the aerobic and anaerobic sludge of the subject substances was investigated. The subject pharmaceutical substances with the sole exception of sulfamethoxazole, were found to be particularly persistent both in the aquatic systems and during their treatment with activated sludge. The biodegradation of sulfamethoxazole was achieved under aerobic conditions in which the substance served both as carbon and nitrogen source for the enriched consortium (i.e. whenever there was a shortage of a carbon or a nitrogen source). As far as the adsorption of the subject substances on soil and on sludge is concerned, the distribution coefficients measured varied depending on the nature of substance and solid material. Ofloxacin was particularly strongly adsorbed (except for the case of using anaerobic biomass for the solid matrix), while clofibric acid was found to be weakly adsorbed. The adsorption of subject substances proved to depend considerably on the pH of system and on the ionic strength. Finally, the fate of pharmaceuticals in soil was also assessed using lysimeter studies. Important parameters investigated included: the pharmaceutical loading rate and the hydraulic loading rate for adsorption and the rate and duration of a “rain” event for desorption. Significant differences in the mobility of the six pharmaceuticals were found and they were correlated with the adsorption/desorption properties of the compounds, the amount of drug applied, the intensity of the “rain” events and the type of the soil.