Analytical, toxicological and kinetic investigation of decomposition of the drug diclofenac in waters and wastes using gamma radiation

Degradation of Selected Antidepressants Sertraline and Citalopram in Ultrapure Water and Surface Water Using Gamma Radiation

Gamma radiation was applied to degradation selected antidepressants in ultrapure water and surface water. Additionally, the influence of typical radical scavengers like carbonate, nitrate and humic acid was determined. The cytotoxicity towards liver cells HepG2 and colon cells Caco2 were measured during the radiation process. It was found that radiation technology, specifically ionizing radiation, can achieve satisfactory degradation efficiency with both SER and CIT. It was shown that the process of decomposition of the tested antidepressants with the highest efficiency occurs in the reaction with the hydroxyl radical.

Atorvastatin-Eluting Contact Lenses: Effects of Molecular Imprinting and Sterilization on Drug Loading and Release

Statins are receiving increasing attention in the ophthalmic field. Their activity as 3-hydroxy-3-methylglutaryl–CoA (HMG–CoA) reductase inhibitors is clinically used to regulate cholesterol levels and leads to pleiotropic effects, which may help in the management of diabetes-related ocular pathologies. This work aims to design bioinspired contact lenses (CLs) with an affinity for atorvastatin by mimicking the active site of HMG–CoA reductase. Sets of imprinted and nonimprinted 2-hydroxyethyl methacrylate (HEMA) hydrogels were synthesized, varying the contents in functional monomers that bear chemical groups that resemble those present in HMG–CoA reductase, namely, ethylene glycol phenyl ether methacrylate (EGPEM), 2-aminoethyl methacrylate hydrochloride (AEMA), and N-(3-aminopropyl) methacrylamide hydrochloride (APMA). The hydrogels were characterized in terms of suitability as CLs (solvent uptake, light transmission, mechanical properties, and biocompatibility) and capability to load and release atorvastatin. Three sterilization protocols (steam heat, gamma radiation, and high hydrostatic pressure) were implemented and their effects on hydrogel properties were evaluated. Copolymerization of AEMA and, particularly, APMA endowed the hydrogels with a high affinity for atorvastatin (up to 11 mg/g; K_N/W > 200). Only high hydrostatic pressure sterilization preserved atorvastatin stability and hydrogel performance. Permeability studies through the porcine cornea and sclera tissues revealed that the amount of atorvastatin accumulated in the cornea and sclera could be effective to treat ocular surface diseases.

Repurposing sodium diclofenac as a radiation countermeasure agent: A cytogenetic study in human peripheral blood lymphocytes

We assessed the radioprotective and mitigative actions of sodium diclofenac, a non-steroidal anti-inflammatory drug using cultured human peripheral blood as a model. Both pre- and post-irradiation treatments with the drug reduced gamma radiation-induced formation of dicentric chromosome, cytochalasin-blocked micronuclei and γ-H2AX foci in human peripheral blood lymphocytes. This work supports the concept that sodium diclofenac may be a useful radiation countermeasure agent.

Photocatalytic Degradation of Diclofenac Using Al2O3-Nd2O3 Binary Oxides Prepared by the Sol-Gel Method

This paper reports the sol-gel synthesis of Al2O3-Nd2O3 (Al-Nd-x; x = 5%, 10%, 15% and 25% of Nd2O3) binary oxides and the photodegradation of diclofenac activated by UV light. Al-Nd-based catalysts were analyzed by N2 physisorption, XRD, TEM, SEM, UV-Vis and PL spectroscopies. The inclusion of Nd2O3 in the aluminum oxide matrix in the 10-25% range reduced the band gap energies from 3.35 eV for the γ-Al2O3 to values as low as 3.13-3.20 eV, which are typical of semiconductor materials absorbing in the UV region. γ-Al2O3 and Al-Nd-x binary oxides reached more than 92.0% of photoconverted diclofenac after 40 min of reaction. However, the photocatalytic activity in the diclofenac degradation using Al-Nd-x with Nd2O3 contents in the range 10-25% was improved with respect to that of γ-Al2O3 at short reaction times. The diclofenac photoconversion using γ-Al2O3 was 63.0% at 10 min of UV light exposure, whereas Al-Nd-15 binary oxide reached 82.0% at this reaction time. The rate constants determined from the kinetic experiments revealed that the highest activities in the aqueous medium were reached with the catalysts with 15% and 25% of Nd2O3, and these compounds presented the lowest band gap energies. The experimental results also demonstrated that Nd2O3 acts as a separator of charges favoring the decrease in the recombination rate of electron-hole pairs.

Contaminants of Emerging Concern Removal by High-Energy Oxidation-Reduction Processes: State of the Art

The presence of ‘emerging contaminants’, i.e., chemicals yet without a regulatory status and poorly understood impact on human health and environment, in wastewater and aquatic environments is widely reported. No established technology, to date, can simultaneously and completely remove all these contaminants, even though some Advanced Oxidation Processes (AOPs,) have demonstrated capacity for some degradation of these compounds. High-energy, radiolytic processing of water matrices using various sources: electron beam (EB), ɣ-rays or non-thermal plasma (NTP) have shown excellent results in many applications, although these remain at the moment isolated examples and scarcely known. High-energy irradiation constitutes an additive-free process that uses short-lived, highly reactive radicals (both oxidating and reducing) generated by water radiolysis, which can instantaneously decompose organic pollutants. Several studies have demonstrated its effectiveness, as a stand-alone process or combined with others, in the rapid decomposition (up to complete mineralization) of organic compounds in pure and complex solutions, and in the removal or inactivation of microorganisms and parasites, without production of leftover residual compounds in solution. High-energy oxidation processes (a.k.a. Advanced Oxidation & Reduction Processes—AORPs) could have a primary role in future strategies addressing emerging contaminants.

Photocatalytic degradation of trace carbamazepine in river water under solar irradiation

An interesting ZnIn₂S₄/TiO₂ composite catalyst was prepared by a hydrothermal method and thoroughly characterized. The photocatalytic degradation of trace carbamazepine (CBZ) in two river waters was primarily investigated through a batch experiment under solar irradiation, and the effects of dissolved organic matter (DOM), inorganic salt (IS), suspended solids (SS) and ultraviolet (UV) on CBZ degradation were researched. The influential degree was DOM ≈ IS » SS and CBZ with an initial concentration of 100 μg/L in the Bahe River water was completely degraded under a catalyst dosage of 75 mg/L and solar irradiation of 240 min. Compared with direct photolysis, the reaction rate constant enhanced 45 times and the half-life reduced to 1/82 in photocatalysis after the removal of all SS, IS and DOM. A certain adsorption capacity of composite catalyst with a specific surface area of 91.9 m²/g and a strong interaction between TiO₂ and ZnIn₂S₄ effectively improved the photocatalytic degradation of CBZ. The increase of light intensity was confirmed to be of benefit to CBZ photocatalysis. Most of CBZ was degraded by visible light and UV effect was negligible. Although photo-etching and acidic corrosion by course products had negative effect on ZnIn₂S₄/TiO₂, the removal of CBZ was mainly kept at 86% after five times usage of the catalyst.

Direct and indirect electrochemical oxidation of amine-containing pharmaceuticals using graphite electrodes

This study investigated the direct and indirect electro-oxidation of amine-containing pharmaceuticals (acetaminophen (ACT), diclofenac (DIC), and sulfamethoxazole (SMX)) by using graphite electrodes, and to compare the influence by using different electrolytes (Na₂SO₄ and NaCl). Under the optimum conditions of current (I) at 0.5 A, in direct system, 74.3%, 90.0%, 81.6% of ACT, DIC, and SMX were respectively removed after 60 min (k = 0.023, 0.037, 0.027 min^-1), 48.9%, 85.9%, 68.2% of TOC respectively removed after reaction time. In contrast, at the same current intensity, in indirect system, ACT, DIC, and SMX were eliminated within 30 min (k = 0.117, 0.307, 0.170 min^-1), 89.6%, 92.6%, 99.6% of TOC respectively removed after reaction time. The results indicated that the dissociated compounds were attracted to the anode due to electrostatic forces and had higher mass transformation rates in the direct electro-oxidation process. According to the cyclic voltammogram, indirect oxidation occurred when active chlorine species were generated from chloride ions anodically to destroy pollutants. Based on intermediates detected during electro-oxidation treatment by ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS), only oxidized intermediates were found in the direct oxidation system, while both oxidized and chlorinated intermediates were found in the indirect oxidation system.

Comparison of different advanced degradation processes for the removal of the pharmaceutical compounds diclofenac and carbamazepine from liquid solutions

Carbamazepine and diclofenac are two examples of drugs with widespread geographical and environmental media proliferation that are poorly removed by traditional wastewater treatment processes. Advanced oxidation processes (AOPs) have been proposed as alternative methods to remove these compounds in solution. AOPs are based on a wide class of powerful technologies, including UV radiation, ozone, hydrogen peroxide, Fenton process, catalytic wet peroxide oxidation, heterogeneous photocatalysis, electrochemical oxidation and their combinations, sonolysis, and microwaves applicable to both water and wastewater. Moreover, processes rely on the production of oxidizing radicals (•OH and others) in a solution to decompose present pollutants. Water radiolysis-based processes, which are an alternative to the former, involve the use of concentrated energy (beams of accelerated electrons or γ-rays) to split water molecules, generating strong oxidants and reductants (radicals) at the same time. In this paper, the degradation of carbamazepine and diclofenac by means of all these processes is discussed and compared. Energy and byproduct generation issues are also addressed.

Can radiation chemistry supply a highly efficient AO(R)P process for organics removal from drinking and waste water? A review

The increasing role of chemistry in industrial production and its direct and indirect impacts in everyday life create the need for continuous search and efficiency improvement of new methods for decomposition/removal of different classes of waterborne anthropogenic pollutants. This review paper addresses a highly promising class of water treatment solutions, aimed at tackling the pressing problem of emerging contaminants in natural and drinking waters and wastewater discharges. Radiation processing, a technology originating from radiation chemistry studies, has shown encouraging results in the treatment of (mainly) organic water pollution. Radiation ("high energy") processing is an additive-free technology using short-lived reactive species formed by the radiolysis of water, both oxidative and reducing, to carry out decomposition of organic pollutants. The paper illustrates the basic principles of radiolytic treatment of organic pollutants in water and wastewaters and specifically of one of its most practical implementations (electron beam processing). Application examples, highlighting the technology's strong points and operational conditions are described, and a discussion on the possible future of this technology follows.