Ciprofloxacin Solution Research Articles

Sunlight-driven charge separation for a heterojunction of nano-pyramidal CuWO4-MOF modified TiO2 nanoflakes for photocatalytic degradation of ciprofloxacin

The study presents a breakthrough of a balanced charge separation for heterojunction CuWO4-TiO2 cocatalyst to efficiently enhance visible light photocatalytic degradation of ciprofloxacin (CIP). A solvothermal-synthesized nanopyramid-like CuWO4 semiconductor was assembled before sol–gel treatment with TiO2 precursors to generate CuWO4-TiO2 nanocomposites. The optical, structural, and morphological properties of CuWO4-TiO2 were elucidated using UV–Vis DRS, XRD, FTIR, Raman spectroscopy, and TEM/SEM techniques. The UV–Vis DRS spectroscopy of as-synthesized CuWO4-TiO2 cocatalyst demonstrated enhanced visible light absorbance. The XRD patterns of CuWO4-TiO2 revealed a triclinic phase nanocrystal. The O-Ti–O functionality was confirmed by FTIR spectroscopy. The photoactive bands corresponding to anatase redshift were observed from Raman spectroscopy of CuWO4-TiO2 nanocomposite. The PL studies attributed this redshift to the elevated extra energy bands that aid electron/hole pair charge separation in a co-catalyst heterojunction CuWO4-TiO2 nanocomposite afforded by embedding CuWO4-MOF within TiO2 crystalline. The TEM showed that un-sintered CuWO4.MOF mimicked a pyramidal shape and converted to nanoflakes upon sintering, while TiO2 and CuWO4-TiO2 retained a tetragonal shape. The photocatalytic activity of CuWO4-TiO2 cocatalyst was studied using CIP, as a model pollutant. The innovative design of 5CuWO4-TiO2 charge separation nanocomposite completely degraded 10 mg L−1 CIP solution at pH = 6.31 (natural pH) and 9 under 120 min of sunlight irradiation.

Determination of quinolone antibiotics in surface water by MnFe2O4@TiO2 magnetic solid phase extraction-high performance liquid chromatography

The magnetic solid phase extraction material (MnFe2O4@TiO2) was prepared by coating TiO2 on MnFe2O4 through an in-situ formation method. The structure and properties of MnFe2O4@TiO2 were characterized by X-ray diffractometer (XRD), scanning electron microscope (SEM), nitrogen adsorption–desorption experiment, and vibrating sample magnetometer (VSM). The conditions for magnetic solid phase extraction (MSPE) of quinolone antibiotics were optimized, and an MSPE-HPLC method was established to determine quinolone antibiotics in water samples. The optimal conditions for MSPE are MnFe2O4@TiO2 amount of 15 mg, extraction time of 15 min, 5 mL of methanol solution with 20 % ammonia as eluent, and elution time of 1 min. Under the optimal conditions, 50 mL 0.1 mg/L mixed standard solutions of fleroxacin, ofloxacin, norfloxacin, ciprofloxacin, and enrofloxacin have achieved enrichment multiples of 67.8, 72.1, 59.6, 55.8, and 60.7, respectively. The linear range of five antibiotics determined by MSPE-HPLC is 0.004–1 mg/L with the relative standard deviations (RSDs) of 2.1 %–4.9 % and the limits of detection (LODs) of 0.0006–0.0020 mg/L. The method is applied to the determination of the five antibiotics in rice paddy water and fish pond water; the recoveries range from 78.9 to 105.8 %, and the RSDs (n = 5) are 3.6 %–8.7 %.

Application of a pm-rf-APGD-type plasma brush for deactivation of antibiotics from liquid solutions leads to impaired development of drug resistance by bacterial pathogens

The presence of antibiotics residuals in the natural environment contributes to development and spread of drug resistance determinants among bacteria, often including clinically significant human pathogens. To tackle with this threat, we constructed a plasma brush, generating pulse-modulated radio-frequency atmospheric pressure glow discharge (pm-rf-APGD), named pm-rf-APGD-type plasma brush, intended for degradation of biologically active pharmaceuticals from both single- and five-component solutions of ciprofloxacin (CFX), enrofloxacin (EFX), ofloxacin (OFX), doxycycline (DXC), and trimethoprim (TMP). The mean antibiotics removal efficiency, achieved mainly due to the action of reactive oxygen species (ROS), was 93.3 %. This removal efficiency corresponded to a mean 62.7% decrease in the antibacterial activities. We revealed the transformation products resulting from an oxygen attack and/or internal fragmentation of the treated pharmaceuticals. Based on a laboratory evolution study, bacterial exposure to the pm-rf-APGD-treated drug lead to significantly lower rates of antibiotic resistance development in juxtaposition with a long-term exposure to the sublethal dose of the active molecules. Thus, we anticipate a great potential of high-throughput, continuous flow, eco-friendly pm-rf-APGD-type plasma brush for routine decontamination processes in the future disposal pipelines of pharmaceuticals-containing wastewaters.

Preferential degradation of ofloxacin on all-organic molecularly imprinted PDI/g-C3N4 photocatalyst via specific molecular recognition

Preferential degradation are urgently needed for detoxification of organic pollutants. Herein, a novel all-organic molecularly imprinted photocatalyst was first constructed by grafting molecularly imprinted perylenediimide (PDI) on graphite-phase carbon nitride (MIP-PDI/g-C3N4) using ofloxacin as template molecule. MIP-PDI/g-C3N4 exhibits higher adsorption capacity for ofloxacin than the non-imprinted counterpart (NIP-PDI/g-C3N4), and shows superior molecular recognition in the mixed solution of ofloxacin and ciprofloxacin. The partition coefficient of MIP-PDI/g-C3N4 for ofloxacin is 3.19 times that for ciprofloxacin, and selection factor of MIP-PDI/g-C3N4 is 1.84 times of NIP-PDI/g-C3N4, suggesting good molecular recognition of MIP-PDI/g-C3N4. The excellent molecular recognition endowed MIP-PDI/g-C3N4 with preferential degradation performance, leading to effective mineralization and detoxification of ofloxacin solution. Most importantly, the preferential degradation mechanism based on molecular recognition was proposed.

Removal of ciprofloxacin by biosulfurized nano zero-valent iron (BP–S-nZVI) activated peroxomonosulfate: Influencing factors and degradation mechanism

Agglomeration and passivation restrict the using zero-valent iron nanoparticles (nZVI). Enhancing the reactivity of nZVI is often accomplished by sulfurization. In this work, nZVI was sulfurized using SRB to produce biosulfurized nano zero-valent iron (BP–S-nZVI), which was then utilized as a catalyst to investigating its performance in an advanced oxidation process based on activated peroxomonosulfate (PMS). When the S/Fe was 0.05, 0.4 g/L of catalyst and 0.5 mM PMS were added to a 20 mg/L ciprofloxacin solution. In 120 min, a 90.4% clearance rate was reached. When the initial pH of the solution was within the range of 3–11, all exhibited acceptable degradation performance and were minimally affected by co-existing anions. In this activation system, hydroxyl, superoxide and sulfate radicals (•OH, O2•− and SO4•−, respectively) have been proven to be the main active species. Seven intermediates in the degradation process of CIP were identified by LC-MS analysis and two possible degradation pathways were proposed. In addition, the degradation rate of CIP was still able to reach 87.0% after five cycles, and the removal rate remained unchanged in the CIP solution with actual water samples as background. This study demonstrated that BP-S-nZVI as a catalyst for the activation of PMS for CIP degradation can still show good reactivity, which provides more possibilities for the practical application of BP-S-nZVI in the degradation of pollutants.

The removal of ciprofloxacin from water by Alue Naga and Leungah beach sand

Abstract Ciprofloxacin is one of the antibiotics used in various fields such as medical, pharmaceutical, and aquaculture. Excessive use and waste treatment that is not in accordance with procedures cause antibiotic pollution which is very dangerous for living things. This study aims to determine the ability of Alue Naga and Leungah beach sand to overcome the problem of ciprofloxacin pollution from water. Both beach sand was characterized using Fourier Transform Infra-Red (FTIR). Before the adsorption test, a stability test of ciprofloxacin solution was conducted for 6 days of testing with two different temperatures (11°C and 30°C). From the test, it was found that ciprofloxacin tends to remain stable at temperatures ranging from 11°C to 30°C. The adsorption capacity of Alue Naga and Leungah sand was 0.56 mg/g and 0.68 mg/g at 30 mg/L concentration after 3 hours of contact time. Meanwhile, in the adsorption process combined with Fenton-like, the percentage of ciprofloxacin removal in Alue Naga beach sand was 31.78% and Leungah beach sand was 44.3%. From this test, it is concluded that the combination of adsorption and Fenton-like methods enhances the capability of adsorbents to effectively remove contaminated ciprofloxacin antibiotics from water.

Recommendations for topical antimicrobial therapy of inflammatory diseases of the middle ear based on the results of evidence-based clinical study

Introduction. In conditions of widespread resistance of pathogens to traditional antimicrobial drugs, active attention is paid to the development of topical antimicrobial drugs for the effective treatment of inflammatory pathology of the middle ear.Aim. To study the efficacy and safety of a new dosage form of the drug Dioxydin® (2.5 mg/ml ear drops) in the treatment of patients with acute purulent otitis media and exacerbation of chronic purulent otitis media in comparison with ear drops containing 0.3% ciprofloxacin solution.Materials and methods. A multicenter randomized comparative clinical trial included adults with acute purulent otitis media or exacerbation of chronic purulent otitis media and during 6 face-to-face visits (days 1st, 3rd, 6th, 9th, as well as a therapy completion visit and a follow-up visit), the effect of drugs was evaluated according to examination, otoscopy, microbiological and audiometric examinations. Safety was assessed by the frequency of adverse events and the results of blood, urine tests and vital signs.Results. The achievement of the primary criteria was evaluated among 164 participants randomized into 2 groups: the proportion of patients with no indications for systemic antibacterial therapy at Visit 2 and with no ear pain at Visit 4, Dioxydin® ear drops had no less effectiveness than the comparison drug (64.6 and 89.9% versus 68.3 and 87.3%, respectively). In terms of the frequency of elimination of the pathogen and improvement of air conduction, the compared drugs also had no statistically significant differences, and according to some secondary criteria, Dioxydin® significantly exceeded 0.3% ciprofloxacin solution (the proportion of patients with a pronounced decrease in pain and congestion in the ear, as well as hyperemia of the eardrum). According to the safety criteria, the compared drugs had no significant differences.Conclusions. The results of the study confirmed the high efficacy and safety of Dioxydin® ear drops in the treatment of otitis media in adults.

Direct Z-scheme system of UiO-66 cubes wrapped with Zn0.5Cd0.5S nanoparticles for photocatalytic hydrogen generation synchronized with organic pollutant degradation

Optimized fabrication of Z-scheme photocatalyst based on MOF materials offers sustainable energy generation and environmental improvement due to their attractive properties. The Z-scheme heterojunctions consisting of UiO-66 cubes covered with Zn0.5Cd0.5S nanoparticles were fabricated by a facile solvothermal method. Thanks to the Z-scheme carrier transport under simulated sunlight irradiation, UiO-66@Zn0.5Cd0.5S exhibited enhanced photocatalytic performance of H2 generation synchronized with organic pollutant degradation in fluoroquinolone antibiotic wastewater. Synergistically, the highest comprehensive performance was obtained in ciprofloxacin solution. The H2 yield reached 224 μmol∙ g−1∙ h−1 and simultaneously the removal efficiency was up to 83.6 %. The degradation pathways revealed that the process of piperazine ring cleavage and decarboxylation also generates H protons, further promoting the production of H2. Therefore, the effective spatial separation and transfer of the photoinduced carriers are attributed to the good band structure, large specific surface area, and cooperative reduction and oxidation reactions of UiO-66@Zn0.5Cd0.5S, resulting in significant photocatalytic activity. The toxicity assessment of antibiotics and intermediate products during the photocatalytic reaction also verifies the reduction of environmental risk. This study highlights a promising way to expand the application of the MOFs-based photocatalyst in clean energy conversion coupling with water remediation.

High potential of the vacuum UV-activated peracetic acid (VUV/PAA) process in eliminating recalcitrant contaminants and waterborne pathogens: Assessing the efficacy of annular and helical reactor configurations

The effectiveness of VUV/PAA in degrading Ciprofloxacin (CIP) and inactivating E. coli was studied. VUV was more efficient than UVC in activating PAA. The VUV/PAA process degraded CIP twice as fast as the VUV process under similar conditions and was more effective in acidic or neutral solutions than in alkaline solutions. The hydroxyl radicals formed were key to the degradation, whereas the R-C species played a lesser role. Furthermore, the VUV/PAA process achieved a satisfactory CIP degradation rate in spiked tap water. Operating the reactors in batch mode, completely degraded CIP in 30 min, and 86.5 % TOC removal was achieved in 120 min of a 40 mg/L CIP solution. In addition, VUV/PAA inactivated a 6.5-log of 1.2 × 109 CFU/mL of E. coli in only 5 min. Moreover, the VUV/PAA process was compared in a helical (HPR) and annular photoreactor (APR); the HPR led to approx. x3 higher ▪OH generation and superior CIP degradation rate. The VUV/PAA process improved CIP degradation in both the APR and HPR with longer hydraulic residence times, where the HPR outperformed the APR in degrading CIP. Overall, the VUV/PAA@HPR system is an effective method for enhancing the degradation of recalcitrant organics and waterborne pathogens in contaminated water, including in the flow-through mode, making it a promising process for water treatment.

The Z-Scheme MIL-88B(Fe)/BiOBr Heterojunction Promotes Fe(III)/Fe(II) Cycling and Photocatalytic-Fenton-Like Synergistically Enhances the Degradation of Ciprofloxacin.

The Z-scheme MIL-88B/BiOBr (referred to as MxBy, whereas x and y are the mass of MIL-88B(Fe) and BiOBr) heterojunction photocatalysts are successfully prepared by a facile ball milling method. By adding low concentration H2O2 under visible light irradiation, the Z-scheme heterojunction and photocatalytic-Fenton-like reaction synergistically enhance the degradation and mineralization of ciprofloxacin (CIP). Among them, M50B150 showed efficient photodegradation efficiency and excellent cycling stability, with 94.6% removal of CIP (10mgL-1) by M50B150 (0.2gL-1) under 90min of visible light. In the MxBy heterojunctions, the rapid transfer of photo-generated electrons not only directly decomposed H2O2 to generate ·OH, but also improved the cycle of Fe3+/Fe2+ pairs, which facilitated the reaction with H2O2 to generate ·OH and ·O2 - radicals. In addition, the effects of photocatalyst dosages, pH of CIP solution, and coexisting substances on CIP removal are systematically investigated. It is found that the photocatalytic- Fenton-like reaction can be carried out at a pH close to neutral conditions. Finally, the charge transfer mechanism of the Z-scheme is verified by electron spin resonance (ESR) signals. The ecotoxicity of CIP degradation products is estimated by the T.E.S.T tool, indicating that the constructed photocatalysis-Fenton-like system is a green wastewater treatment technology.

Superior adsorptive removal of ciprofloxacin by graphene oxide modified Ni-Al layered double hydroxide composites

Pharmaceutical drug removal from industrial wastewater has become a major challenge in recent years. To address this concern, an eco-friendly, non-toxic, renewable, low-cost, and simple-to-synthesize catalyst called Ni-Al LDH (Layered Double Hydroxide) was synthesized using the co-precipitation method. LDH was further constructed with GO (Graphene Oxide) using the electro-self-assembly method for its effective performance in the removal of ciprofloxacin from wastewater. XRD, FESEM, EDX, Raman, FTIR, UV-Vis DRS, and BET analysis were used to characterize the as-prepared Ni-Al LDH and composites of GO@LDH. Using bare LDH and its composite with GO, several parameters such as adsorbent dosage, contact time, adsorbate concentration, and pH were optimized. GO(5)@LDH shows complete adsorption of 87.4% in 180 min for ciprofloxacin solution. The SBET for Ni-Al LDH, GO(1)@LDH, and GO(5)@LDH was determined to be in the order 3.5456 m2/g, 19.575 m2/g, and 22.5591 m2/g, suggesting that the surface area of the LDH increases upon GO loading. According to the calculation based on Langmuir isotherm, GO(5)@LDH (1968.5 mg/g) has a greater maximum adsorption capacity than Ni-Al LDH (332.2 mg/g). The kinetic analysis reveals that it adheres to a pseudo-second-order kinetic model. The catalyst was effectively employed for four repeating cycles with only a 10% decrease in removal rate, demonstrating that it can be easily regenerated. The morphology of the catalyst GO(5)@LDH remained the same before and after use, as seen by the XRD spectra, indicating the stability of the catalyst. As a result, LDH-GO composites are ideal catalysts for the treatment of ciprofloxacin wastes in the environment.

Highly efficient activation of peroxymonosulfate by ZIF-67 anchored cotton derived for ciprofloxacin degradation

Metal–organic framework (MOF) and MOF-derived materials have attracted extensive research interest as environmental catalysts. In this study, a composite material (ZIF-67/CCot-8) was successfully prepared using cotton fiber as a substrate and growing ZIF-67 in situ. This material exhibited excellent catalytic performance and significantly improved the efficiency of antibiotics degradation. ZIF-67/CCot-8 at a concentration of 0.05 g/L, combined with 0.2 mM peroxymonosulfate (PMS), removed approximately 97% of ciprofloxacin (CIP) and 99% of tetracycline and sulfamethoxazole within 15 min. The high catalytic efficiency of this catalyst is mainly attributed to the uniform distribution of ZIF-67-derived nanoparticles on the surface of the cotton fibers, providing abundant active sites and thereby significantly enhancing the efficiency of antibiotics degradation. Radical quenching experiments and electron paramagnetic resonance (EPR) analyses revealed that sulfate radicals (SO4•-) and singlet oxygen (1O2) were the main active species. Mass spectrometry (MS) was used to elucidate the CIP degradation pathway. The growth of the roots and stems of soybean sprouts in different water environments (tap water, treated water, and untreated water) was also observed. The results demonstrated a significant improvement in the inhibition of plant growth in the post-degradation CIP solution, indicating a substantial reduction in the toxicity of the degraded aqueous solution. To validate the practicality of the ZIF-67/CCot-8/PMS system, a continuous-flow water-treatment device was designed. This system removed 98% of the CIP solution within 180 min, demonstrating its excellent durability. This study presents a potential pathway for effective antibiotics removal using MOF-derived materials.

Selective and efficient removal of ciprofloxacin from water by bimetallic MOF beads: Mechanism quantitative analysis and dynamic adsorption

MOFs play an important role in the adsorption of antibiotics, but the drawbacks of MOF powders limit their practical applications. Moreover, the dominant adsorption mechanism and the quantitative assessment of MOF powders are less studied. Herein, bimetallic ZIF particles were embedded in chitosan beads via an in-situ growth process (ZnCo-ZIF@CS beads), which could selectively remove ciprofloxacin (CIP) from a complex environment. The maximum adsorption capacity was 348.90 mg/g, superior to that of other advanced adsorbents. ZnCo-ZIF@CS performed efficiently in various actual water samples and showed excellent anti-interference and recycling abilities (only a decrease of 12.74 % after 9 cycles). CIP adsorption could still reach 85.30 % after continuous flow treatment for 600 min. Interestingly, ZnCo-ZIF@CS had a good protective effect on rice seedling growth and alleviated CIP stress in rice seedlings due to the low metal leaching at pH 4.0–11.0. Macroscopic experiments, XPS, 2D-FTIR-COS and DFT results revealed that hydrogen bonding (HB), complexation (CB), electrostatic attraction (EA) and π-π interactions were involved in CIP adsorption. Different interactions dominated CIP adsorption in different pH regions. At pH < 5.0, EA and CB were the main driving forces, accounting for 42–52 % and 27–57 % of the total adsorption; at 5.0 < pH < 9.0, the contribution of EA decreased to < 15 % while CB was still dominant, accounting for ∼ 50 % of the total adsorption, and other effects (HB and π-π) increased to approximately 29–39 %; at pH > 9.0, EA, CB, HB together with π-π caused 1–27 %, 9–31 % and 66–72 % of the total adsorption, respectively. The reaction sequence of functional groups in different CIP solutions and at various pH values was also probed by 2D-FTIR-COS. This study further provides clear evidence for developing robust MOF-based adsorbents and for the mechanism quantitative analysis of pollutant adsorption by MOFs.

Green synthesis of gold-titania nanoparticles for sustainable ciprofloxacin removal and phytotoxicity evaluation on aquatic plant growth

This study presents an eco-friendly method of synthesis plasmonic gold-titanium (TiO2@Au) nanoparticles, which exhibit enhanced photocatalytic degradation of ciprofloxacin under visible light. The treated effluent was then used to cultivate aquatic plants such as Pistia stratiotes, commonly referred to as water lettuce. In order to verify the success of the synthesis of the green plasmonic gold-titania nanoparticles, various spectroscopic techniques were utilized, including UV–Visible, Raman, Fourier Transform Infrared (FTIR), Powder X-ray Diffraction (XRD), Energy Dispersive X-ray (XPS), and microscopic Transmission Electron Microscopy (TEM) analysis. It is apparent from these images that these nanoparticles, with a diameter of about 10 ± 5 nm, are uniformly distributed on the surface of the TiO2 Anatase nanoparticles. Under visible light conditions, the nanocomposite removes 95 % of a high concentrated solution of ciprofloxacin, as demonstrated the UV–Vis spectrum. The phytotoxicity for one (01) week of the treated effluents demonstrated that the effluent is not harmful for the aquatic plant growth in comparison to the 50 ppm ciprofloxacin solution which exhibits abnormal plant growth. Based on literature reports and observed phenomena, the study also presents a plausible mechanism for the phenomenon.

Cube-shaped Cobalt-doped zinc oxide nanoparticles with increased visible-light-driven photocatalytic activity achieved by green co-precipitation synthesis

From the perspective of environmental protection, the highly efficient degradation of antibiotics and organic dyes in wastewater needs to be tackled as soon as possible. In this study, an ecofriendly and green cube-shaped cobalt-doped zinc oxide nanoparticles (Co–ZnO NPs) photocatalyst using Pterocladia Capillacea (P. Capillacea) water extract loaded with 5, 10, and 15% cobalt ions were formed via co-precipitation process to degrade antibiotics. The prepared Co–ZnO NPs were tested as a photocatalyst for the photodegradation of ciprofloxacin (CIPF) in the presence of a visible LED-light source. Co–ZnO NPs have been obtained through the co-precipitation method in the presence of P. Capillacea extract as a green capping agent and reducing agent, for the first time. Several characterization techniques including FTIR, XRD, BET, XPS, TEM, EDX, SEM, TGA and DRS UV–Vis spectroscopy were applied to study the prepared Co–ZnO NPs. XRD results suggested that the average size of these NPs ranged between 42.82 and 46.02 nm with a hexagonal wurtzite structure. Tauc plot shows that the optical energy bandgap of ZnO NPs (3.19 eV) gradually decreases to 2.92 eV by Co doping. Examinations showed that 5% Co–ZnO NPs was the highest efficient catalyst for the CIPF photodegradation when compared with ZnO NPs and other 10 and 15% Co–ZnO NPs. A 10 mg/L solution of CIPF was photo-degraded (100%) within the first 15 min irradiation. The kinetics showed that the first-order model is suitable for displaying the rate of reaction and amount of CIPF elimination with R2 = 0.952. Moreover, central composite design optimization of the 5% Co-doped ZnO NPs was also investigated.

Nanotubes/nanorods-like structures of La-doped ZnO for degradation of Methylene Blue and Ciprofloxacin

In this study, nanotubes/nanorods-like structures of Zn0.97La0.03O compound were synthesized at different pH values (pH = 8, 9, 10, 11, and 12), and the photocatalytic response for Methylene Blue (MB) dye and Ciprofloxacin (CIP) drug were investigated. It was verified that the pH variation directly impacts the ZnO crystal structure, morphology, optical and photocatalytic properties. The basic and alkaline pH values cause a decrease in the crystallite size and these differences may have contributed to the band gap energy values variations. Oxygen vacancy defects (VO, VO+, and VO++) were abundant in the La-doped ZnO samples, which also demonstrated to be formed from mesopores, as seen in N2 adsorption/desorption results. The photocatalytic response of the materials was verified in MB and CIP solutions under UV irradiation conditions. The sample synthesized at pH 9 (ZL9) demonstrated greater capacity to remove MB (91.45 %) and CIP (87.6 %) in typical pseudo-first-order kinetics. Using different inhibitors, it was observed that the •OH radicals were the species involved in the photocatalysis of pollutants for the ZL9 sample. In addition, this material demonstrated a satisfactory ability to remove pollutants even after three consecutive uses. This study demonstrates that pH is an important parameter to consider in the synthesis process of ZnO nanostructures, directly influencing the structural, optical, and morphological properties and the degradation of highly dangerous dyes and drugs.

A novel approach in the synthesis of CdS/titania nanotubes array nanocomposites to obtain better photocatalyst performance

Studies that seek to improve the performance of photocatalyst continue to develop. Several observations have been made on the effect of using ultrasonic waves during the synthesis process of CdS/Titania Nanotubes Array (CdS/TiNTA) nanocomposites on an ability to degrade ciprofloxacin solution (CIP) and produce hydrogen. Therefore, the nanocomposite synthesis process uses the Successive Ionic Layer Adsorption and Reaction (SILAR) method, with (CH3COO)2Cd and Na2S as the precursors. During the SILAR process, sonication was applied for 60 minutes and carried out in the amorphous phase of TiO2 to increase the effectiveness of contact between the two semiconductors. The synthesis results were confirmed in term of their crystallinity, morphology, the presence of components on the surface, and the shift of bandgap by means of XRD, FESEM, FTIR, and UV-Vis DRS characterization, respectively. Photocatalytic activities of the nanocomposites were evaluated in a system containing 10 ppm CIP solution, on the purpose of observing their ability to degrade CIP and produce hydrogen. Our findings revealed an improvement in crystallinity, successful semiconductor coupling, and a band gap narrowing in the synthesized nanocomposites. Furthermore, the photocatalysts synthesized in the amorphous TiO2 and by sonication during SILAR offered doubled production capacity of hydrogen (0.191 mmol/m2) as compared to photocatalysts synthesized without sonication (0.092 mmol/m2). Compared to similar photocatalysts synthesized using the SILAR method in the crystalline phase, photocatalysts synthesized in the amorphous phase exhibited four-fold higher hydrogen production (0.044 to 0.191 mmol/m2). This prominent ability of the nanocomposites is related to the success of CdS adhering well to TiO2 surface to form nanocomposites, so that the bandgap energy position of CdS that is strong in the reduction reaction greatly contributes to improve the performance of the resulting photocatalyst, which is very advantageous in terms of its ability in water-splitting reactions.

Simultaneous assessment of ciprofloxacin and dexamethasone in ocular tear fluid by LC-MS/MS: Application to a pharmacokinetic study in rabbits

• Robust and fast method for estimation of CFX and DEX in rabbit tears, aqueous humor, and corneal biofluids using LC-MS/MS were established. • The developed method was successfully validated as per USFDA guidelines. • Simple precipitation technique used for extraction. • The method was applied for the pharmacokinetic study of marketed CFX and DEX eye drop solution in NZ Albino Rabbits. • PK/PD indices and simulation were estimated. A simple and fast LC-MS/MS method was developed and validated for simultaneous quantitation of ciprofloxacin (CIP) and dexamethasone (DEX) in tear fluid and partially validated for aqueous humor and cornea. Samples were cleaned- up by single-step precipitation using methanol as an anti-solvent. Agilent SB C 18 column with a total run time of 4.5 min was used for chromatographic separation utilizing isocratic mode. MS detection was carried out by a triple quadrupole tandem mass spectrometer (TQMS) in the multiple reaction monitoring (MRM) modes utilizing a positive electrospray ionization (+ESI). The developed method showed a wide analytical range (CIP: 0.7812 – 200 ng/mL and DEX: 1.875- 240 ng/mL) with good linearity (r 2 > 0.998) and acceptable accuracy and precision. It also showed excellent recoveries (> 85% for all analytes) and a negligible matrix effect. Finally, this method was successfully applied to the pharmacokinetic (PK) profile of clinically used eye drop solution of CIP and DEX (CiploxD) in preclinical rabbit tears, suggesting its suitability for PK profiling and PK-based dosage regimen design against various pathogens.

Self‐Targeted Co‐Delivery of an Antibiotic and a Cancer‐Chemotherapeutic from Synthetic Liposomes for the Treatment of Infected Tumors

AbstractIntra‐tumor bacteria promote tumor growth and inactivate cancer‐chemotherapeutics, causing poor treatment prognoses. Combined administration of cancer‐chemotherapeutics and antibiotics may disturb the oral and intestinal microflora in critically‐ill patients. To establish intra‐tumor co‐delivery of cancer‐chemotherapeutics and antibiotics, gemcitabine and ciprofloxacin are loaded in so‐called “self‐targeting”, highly blood‐compatible, synthetic DCPA‐H2O liposomes equipped with complexed water for pH‐responsiveness. Liposomal pH‐responsiveness can be maintained by in‐shell loading of gemcitabine and in‐core loading of ciprofloxacin. These dual‐loaded liposomes are stealthily transported in the blood circulation to accumulate in the acidic environment of an infected tumor. Upon tumor self‐targeting, liposomes are fused with tumor cells and infecting bacteria and are disassembled to simultaneously release gemcitabine and ciprofloxacin. Treatment of mice with these self‐targeting liposomes yields significantly higher responses of Escherichia coli infected tumors with respect to both infection and tumor volume than gemcitabine and ciprofloxacin co‐delivered from non‐self‐targeting liposomes or free gemcitabine with or without ciprofloxacin in solution.

Structural Integrity of Absorbable Gelatin Sponges for Middle Ear Packing in Otologic Surgery

This study investigates the physical properties upon immersion of two gelatin sponges commonly used in otologic surgery. Absorbable gelatin sponges are often used in middle ear surgery to achieve hemostasis and, perhaps more importantly, to provide a "scaffolding" to support ossicular chain and/or tympanic membrane reconstructions. Their rate of dissolution may therefore affect the success of tympanic membrane closure. An in vitro study was conducted to quantify the material changes of two absorbable gelatin sponges, a standard-density sponge and one with fewer collagen cross-linkages (low-density sponge). Volume loss (%) in 0.9% saline, 0.3% ciprofloxacin, and/or 0.1% dexamethasone as single-agent otic drops in a combination formulation was measured at 15-minute intervals for the first hour and at days 1, 3, and 5 postimmersion. Secondary end points included compressibility, porosity under microscopy, and infrared spectroscopy analysis. The low-density sponge immersed in any of the three otic solutions showed a statistically significant greater volume loss at all time points when compared with the standard-density sponge (27.2% ± 5.4% vs. 15.4% ± 6.0% at 15 minutes and 44.8% ± 5.1% vs. 34.6% ± 2.9% at 5 days, p < 0.001). Interestingly, both sponges immersed in normal saline had lost almost half of their original volume after 15 minutes when compared with samples immersed in an otic solution (48.3% ± 4.6% vs. 21.3% ± 8.3%, respectively, p < 0.001). The standard-density sponge immersed in an otic solution of ciprofloxacin, dexamethasone, or a combination formulation best maintained its structural integrity. Ancillary in vivo studies are required to assess the hemostatic properties, surgical outcomes, and middle ear synechiae of the above study conditions. Foundational evidence.