Pharmacokinetics of the Recalcitrant Drug Lamotrigine: Identification and Distribution of Metabolites in Cucumber Plants

Treated wastewater is an important source of water for irrigation. As a result, irrigated crops are chronically exposed to wastewater-derived pharmaceuticals, such as the anticonvulsant drug lamotrigine. Lamotrigine is known to be taken up by plants, but its plant-derived metabolites and their distribution in different plant organs are unknown. This study aimed to detect and identify metabolites of lamotrigine in cucumber plants grown for 35 days in a hydroponic solution by using LC-MS/MS (Orbitrap) analysis. Our data showed that 96% of the lamotrigine taken up was metabolized. Sixteen metabolites possessing a lamotrigine core structure were detected. Reference standards confirmed two; five were tentatively identified, and nine molecular formulas were assigned. The data suggest that lamotrigine is metabolized via N-carbamylation, N-glucosidation, N-alkylation, N-formylation, N-oxidation, and amidine hydrolysis. The metabolites LTG-N2-oxide, M284, M312, and M370 were most likely produced in the roots and were translocated to the leaves. Metabolites M272, M312, M314, M354, M368, M370, and M418 were dominant in leaves. Only a few metabolites were detected in the fruits. With an increasing exposure time, lamotrigine leaf concentrations decreased because of continuous metabolism. Our data showed that the metabolism of lamotrigine in a plant is fast and that a majority of metabolites are concentrated in the roots and leaves.

Wastewater-derived organic contaminants in fresh produce: Dietary exposure and human health concerns

Irrigation with reclaimed wastewater is a growing practice aimed at conserving freshwater sources, especially in arid and semiarid regions. Despite the apparent advantages to water management, the practice of irrigation with reclaimed wastewater exposes the agroenvironment to contaminants of emerging concern (CECs). In this report, we estimated the unintentional dietary exposure of the Israeli population (2808 participants) to CECs from consumption of produce irrigated with reclaimed wastewater using detailed dietary data obtained from a National Health and Nutrition Survey (Rav Mabat adults; 2014-2016). Human health risk analyses were conducted based on acceptable daily intake (ADI) and threshold of toxicological concern (TTC) approaches. The highest unintentional exposure to wastewater-borne CECs was found to occur through the consumption of leafy vegetables. All analyzed CECs exhibited hazard quotients <1 for the mean- and high-exposure scenarios, indicating no human health concerns. However, for the extreme exposure scenario, the anticonvulsant agents lamotrigine and carbamazepine, and the carbamazepine metabolite epoxide-carbamazepine exhibited the highest exposure levels of 29,100, 27,200, and 19,500 ng/person (70 kg) per day, respectively. These exposure levels exceeded the TTC of lamotrigine and the metabolite epoxide-carbamazepine, and the ADI of carbamazepine, resulting in hazard quotients of 2.8, 1.1, and 1.9, respectively. According to the extreme estimated scenario, consumption of produce irrigated with reclaimed wastewater (leafy vegetables in particular) may pose a threat to human health. Minimizing irrigation of leafy vegetables using reclaimed wastewater and/or improving the quality of the reclaimed wastewater using an advanced treatment would significantly reduce human dietary exposure to CECs.

Effects of membrane transport activity and cell metabolism on the unbound drug concentrations in the skeletal muscle and liver of drugs: A microdialysis study in rats

The unbound concentrations of 14 commercial drugs, including five non-efflux/uptake transporter substrates-Class I, five efflux transporter substrates-class II and four influx transporter substrates-Class III, were simultaneously measured in rat liver, muscle, and blood via microanalysis. Kpuu,liver and Kpuu,muscle were calculated to evaluate the membrane transport activity and cell metabolism on the unbound drug concentrations in the skeletal muscle and liver. For Class I compounds, represented by antipyrine, unbound concentrations among liver, muscle and blood are symmetrically distributed when compound hepatic clearance is low. And when compound hepatic clearance is high, unbound concentrations among liver, muscle and blood are asymmetrically distributed, such as Propranolol. For Class II and III compounds, overall, the unbound concentrations among liver, muscle, and blood are asymmetrically distributed due to a combination of hepatic metabolism and efflux and/or influx transporter activity.

Pharmacotherapy for depression and bipolar disorder during lactation: A framework to aid decision making

OBJECTIVE

Breastmilk is recommended as the exclusive source of nutrition for infants younger than 6 months due to the numerous health benefits for both infants and mothers. Although many women are prescribed medications during pregnancy and postpartum, limited data are available to assist women in weighing the benefits compared to the risks of peripartum medication use. The goals of this paper are to discuss the importance of breastmilk for the health of both the mother and infant, evaluate the impact of medication use on women's infant feeding choice, describe the transfer of drugs to breastmilk and infants, and provide a framework for clinicians to support evidence-based counseling for women treated for mood disorders.

RECOMMENDATIONS

We recommend early pregnancy counseling to discuss the benefits and risks of medications during breastfeeding. The Surgeon General's Call to Action (2011) highlights the short and long-term negative health effects of not providing breastmilk. Integrating recommendations from the pediatric and obstetric teams allows patients to make decisions based on evidence and reach their infant feeding goals. Databases containing summaries of research findings and pharmacologic properties of the drug of interest are an essential resource for clinicians.

Evaluation of solubility and dissolution of lamotrigine using lipid based microparticulate carriers: An in-vitro analysis

The present study was designed to develop novel lipid microparticles in order to improve solubility, dissolution and bioavailability of a lipophilic drug of BCS class II, lamotrigine. For that purpose, increase in solubility of the model drug was investigated using different lipids and the promising lipids were further used for the fabrication of microparticles. Solid lipid (GMS) and liquid lipid (olive oil) were used along with an emulsifier (Tween 80) and a stabilizer (Poloxamer 188) to prepare mircoparticles by melt emulsification method. Prepared formulations were characterized for physicochemical properties such as solubility, particle size, zeta potential, polydispersity index and entrapment efficiency. In vitro dissolution studies were carried out in 0.01 N HCl for 24 h. The findings provided that the solubility of lamotrigine was reasonably increased in GMS, olive oil, Tween 80 and poloxamer 180. The lamotrigine solubility was increased 4.92 fold with G4 microparticles formulation. Size analysis revealed that the microparticles were in range of 11.1 to 178.8 μm and the zeta potential values were from -13 to -20 mV. Microparticles prepared with solid and liquid lipids exhibited satisfactory entrapment efficiency ranging from 59 to 87%. Conclusively, the outcomes of the studies suggest the appropriateness of selected ingredients for improving solubility as well as loading of lamotrigine in microparticles for its sustained and effective delivery.

Transformation of lamotrigine by white-rot fungus Pleurotus ostreatus

One of the most persistent pharmaceutical compounds commonly found in treated wastewater is lamotrigine (LTG). It has also been detected in soils and crops irrigated with treated wastewater. Here we focused on the ability of the white-rot edible mushroom Pleurotus ostreatus to remove and transform LTG in liquid cultures. At concentrations of environmental relevance (1 and 10 μg L^-1) LTG was almost completely removed from the culture medium within 20 days. To elucidate the mechanism of LTG removal and transformation, we applied a physiological-based approach using inhibitors and a competing agent. These experiments were conducted at a higher concentration for metabolites detection. Based on identification of sulfur-containing metabolites and LTG N2-oxide and the effect of specific inhibitors, cytochrome P450 oxidation is suggested as one of the reaction mechanisms leading to LTG transformation. The variety and number of transformation products (i.e., conjugates) found in the current study were larger than reported in mammals. Moreover, known conjugates with glucuronide, glutathione, or cysteine/glycine, were not found in our system. Since the majority of the identified transformation products were conjugates of LTG, this study highlights the persistence of LTG as an organic pollutant in ecosystems exposed to wastewater.