“…By contrast, π-π EDA and hydrophobic interaction still worked 36 . Thus, the adsorption of CIP was continuous, even though these processes were slow.…”
Section: Discussionmentioning
confidence: 92%
“…The 1653 cm −1 vibration of pepsin was attributed to amine I 18 . The broad band at 1040 cm −1 was attributed to Si–O stretch of di and trioctahedral smectites 36 . Meanwhile, the band at 1709 cm −1 obviously disappeared for GO, rGO, and Mont and their mixtures loaded with CIP, indicating that COOH was involved in the interactions.Figure 5FTIR spectra of GO, rGO and Mont under the varying interaction systems after adsorption at the range of 800 to1800 cm −1 at pH 2.
…”
This study investigated the interaction processes of ciprofloxacin (CIP) with graphene oxide (GO) and reduced GO (rGO) in presence of montmorillonite (Mont) in simulated gastrointestinal fluids. The order of CIP adsorption affinity was rGO+Mont > GO+Mont > rGO+Mont+pepsin > rGO > GO+Mont+pepsin > Mont > Mont+pepsin > GO > rGO+pepsin > GO+pepsin in simulated gastric fluid. Mont enhanced the adsorption of CIP on GO and rGO due to hydrated Si species coating on GO and rGO in the simulated gastric fluid. Meanwhile, π–π interaction between CIP and graphene caused the great shift of two cyclopropyl CH2 and one cyclopropyl in CIP molecules. And GO, rGO, and Mont interacted mainly with CIP by COOH groups. CIP and pepsin molecules could intercalate and increase the basal spacing of Mont as well. After the various interaction systems of adsorbent-adsorbate transferring to the simulated intestinal fluid, CIP was continuously adsorbed by GO and rGO. In addition, adsorbed CIP was released from Mont into the solution through electrostatic repulsion. The decrease ratio of CIP was the lowest in the GO/rGO+Mont+pepsin systems. Therefore, the mixture of Mont and GO/rGO decreased the CIP concentration in gastrointestinal fluid to weaken further antibiotic activity of CIP.
“…By contrast, π-π EDA and hydrophobic interaction still worked 36 . Thus, the adsorption of CIP was continuous, even though these processes were slow.…”
Section: Discussionmentioning
confidence: 92%
“…The 1653 cm −1 vibration of pepsin was attributed to amine I 18 . The broad band at 1040 cm −1 was attributed to Si–O stretch of di and trioctahedral smectites 36 . Meanwhile, the band at 1709 cm −1 obviously disappeared for GO, rGO, and Mont and their mixtures loaded with CIP, indicating that COOH was involved in the interactions.Figure 5FTIR spectra of GO, rGO and Mont under the varying interaction systems after adsorption at the range of 800 to1800 cm −1 at pH 2.
…”
This study investigated the interaction processes of ciprofloxacin (CIP) with graphene oxide (GO) and reduced GO (rGO) in presence of montmorillonite (Mont) in simulated gastrointestinal fluids. The order of CIP adsorption affinity was rGO+Mont > GO+Mont > rGO+Mont+pepsin > rGO > GO+Mont+pepsin > Mont > Mont+pepsin > GO > rGO+pepsin > GO+pepsin in simulated gastric fluid. Mont enhanced the adsorption of CIP on GO and rGO due to hydrated Si species coating on GO and rGO in the simulated gastric fluid. Meanwhile, π–π interaction between CIP and graphene caused the great shift of two cyclopropyl CH2 and one cyclopropyl in CIP molecules. And GO, rGO, and Mont interacted mainly with CIP by COOH groups. CIP and pepsin molecules could intercalate and increase the basal spacing of Mont as well. After the various interaction systems of adsorbent-adsorbate transferring to the simulated intestinal fluid, CIP was continuously adsorbed by GO and rGO. In addition, adsorbed CIP was released from Mont into the solution through electrostatic repulsion. The decrease ratio of CIP was the lowest in the GO/rGO+Mont+pepsin systems. Therefore, the mixture of Mont and GO/rGO decreased the CIP concentration in gastrointestinal fluid to weaken further antibiotic activity of CIP.
“…Similar findings reported on the best fit model for the adsorption process based on pseudo-second order kinetic model equation including adsorption of CIP onto montmorillonite, ordered mesoporous carbon (OMC) and bamboo-based carbon (BC), and enrofloxacin and ofloxacin onto bamboo biochar. 15,21,22…”
Section: Pseudo-second Order Kinetic Modelmentioning
In this work, the feasibility of using guava leaves powder (GLP) as an adsorbent to remove ciprofloxacin (CIP) from aqueous solution was investigated. The effectiveness of GLP to remove CIP was studied under different experimental conditions. The optimum pH for the adsorption of CIP was found to be pH 4. The adsorption trend was rapid at the initial stage and equilibrium was achieved in 60 min. The percentage uptake of CIP decreased with increasing initial CIP concentration. The adsorption kinetics was found to conform well to the pseudo-second order kinetic model. Characterisation of GLP was carried out by using field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM) and Fourier-transform infrared (FTIR) spectrophotometry. Both Langmuir and Freundlich isotherm models were applied to describe the equilibrium adsorption data of CIP onto GLP. The maximum adsorption capacity (q m) was found to be 232.56 mg g-1. By applying Plackett-Burman design, contact time and pH were found to be the influential parameters in affecting the uptake of CIP onto GLP.
“…Effect of pH on CIP aqueous solubility calculated using the following equation: S = S 0 1 + 10 (pka 1 −pH) + 10 (pH−pka 2 ) , with pka 1 = 6.2, pka 2 = 8.6[20,75]. Individual values are from Yu et al[76] (empty triangles); McShane et al[20] (plain dot); Blokhina et al[77] (empty diamond; Roca Jalil et al[78] (square). Values were measured between 25 and 30 • C.…”
Pulmonary drug delivery is a promising strategy to treat lung infectious disease as it allows for a high local drug concentration and low systemic side effects. This is particularly true for low-permeability drugs, such as tobramycin or colistin, that penetrate the lung at a low rate after systemic administration and greatly benefit from lung administration in terms of the local drug concentration. However, for relatively high-permeable drugs, such as fluoroquinolones (FQs), the rate of absorption is so high that the pulmonary administration has no therapeutic advantage compared to systemic or oral administration. Formulation strategies have thus been developed to decrease the absorption rate and increase FQs’ residence time in the lung after inhalation. In the present review, some of these strategies, which generally consist of either decreasing the lung epithelium permeability or decreasing the release rate of FQs into the epithelial lining fluid after lung deposition, are presented in regards to their clinical aspects.
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