Pharmacokinetic Behavior and Pharmacokinetic/Pharmacodynamic Integration of Danofloxacin Following Single or Co-Administration with Meloxicam in Healthy Lambs and Lambs with Respiratory Infections

The aim of this study was to determine the pharmacokinetics and pharmacodynamics of danofloxacin (DAN; 6 mg/kg) following subcutaneous administration alone or co-administration with meloxicam (MLX; 1 mg/kg) in healthy lambs and lambs with respiratory infections. The study was carried out using a total of four groups: HD (healthy; n = 6) and ID (infected; n = 7) groups who were administered DAN only, and HDM (healthy; n = 6) and IDM (infected; n = 7) groups who were administered DAN and MLX simultaneously. The plasma concentrations of DAN were determined using high-performance liquid chromatography–UV and analyzed by the non-compartmental method. DAN exhibited a similar elimination half-life in all groups, including both the healthy and infected lambs. The total clearance in the HDM, ID and IDM groups and volume of distribution in the HDM and IDM groups were significantly reduced. MLX in the IDM group significantly increased the area under the curve (AUC) and peak concentration (Cmax) of DAN compared to the HD group. The Mannheimia haemolytica, Escherichia coli, and Streptococcus spp. strains were isolated from bronchoalveolar lavage fluid samples of the infected lambs. When co-administration with meloxicam, DAN at a 6 mg/kg dose can provide optimum values of ƒAUC0–24/MIC (>56 h) and ƒCmax/MIC (>8) for susceptible M. haemolytica isolates with an MIC90 value of 0.25 µg/mL and susceptible E. coli isolates with an MIC value of ≤0.125 µg/mL.

Quantitation of vistusertib by UHPLC-MS/MS in rat plasma and its application to a pharmacokinetic study

Aim: The present study aimed to develop a UHPLC-MS/MS method for determination of vistusertib in biological matrix, and to describe the pharmacokinetic behavior of vistusertib in SD rats. Methodology & results: After protein precipitation with acetone and acetonitrile (1:1), the chromatographic separation was achieved on an Agilent Poroshell 120 EC-C18 column and detected with a SCIEX QTRAP 4500 mass spectrometer under positive ionization mode. The developed UHPLC-MS/MS method showed an excellent linearity within the range of 1.0–3000 ng/ml with good accuracy and precision. Vistusertib showed a rapid absorption and reached the maximum concentration of 3532.2 ± 678.0 ng/ml 20–30 min after oral administration in Sprague-Dawley rats. Conclusion: The established analytical method was fast, sensitive and robust, and successfully applied to describe the pharmacokinetic behavior of vistusertib following an oral administration in rats.

Biopharmaceutical Study on Nobiletin-Loaded Amorphous Solid Dispersion with Improved Hypouricemic Effect

The present study aimed to develop an amorphous solid dispersion of nobiletin (ASD/NOB) using hydroxypropyl cellulose-SSL (HPC-SSL) to improve the pharmacokinetic properties and hypouricemic effect of NOB. ASD/NOB was prepared by the freeze-drying method (ASD/NOB). ASD/NOB was characterized with a focus on crystallinity, dissolution, pharmacokinetic behavior, and hypouricemic action in a rat model of hyperuricemia. ASD/NOB showed significant improvement in dissolution behavior, as evidenced by a 4.4-fold higher dissolved NOB concentration than crystalline NOB at 2 h in distilled water. After the oral administration of ASD/NOB (50 mg NOB/kg) in rats, higher systemic exposure to NOB was observed with an 18-fold enhancement in oral bioavailability, and the Tmax value of orally administered ASD/NOB was 60% shorter than that of orally administered crystalline NOB. In a rat model of hyperuricemia, orally dosed ASD/NOB showed an improved hypouricemic effect by a 16% reduction in the plasma uric acid level compared with orally administered crystalline NOB. Based on these findings, ASD/NOB may be an efficacious dosage option to improve the nutraceutical potential of NOB for the treatment of hyperuricemia.

Pharmacokinetic Study of Anti-osteoarthritic Compounds of a Standardized Fraction from Sphaeralcea Angustifolia

Sphaeralcea angustifolia has been widely used in inflammatory conditions such as blows, bruises, fractures, and wounds. The compounds identified as active in plants and suspension cell culture of S. angustifolia were tomentin, scopoletin, and sphaeralcic acid. To consolidate the integral use of knowledge about the S. angunstifolia and strengthen its pharmacological use in patients with knee osteoarthritis, the pharmacokinetic behavior of the active compounds was characterized. The SaTSS (S. angustifoloia standardized in Tomentin, Scopoletin, and Sphaeralcic acid) anti-ostearthritic fraction was obtained from cell suspension. The analytical method of High-Performance Liquid Chromatography (HPLC) for tomentin, scopoletin, and sphaeralcic acid were validated determining the accuracy, precision linearity, sensibility, specificity, detection limits, and quantification time-range parameters, as well as extraction efficiency and stability of compounds. The pharmacokinetic assay was performed with ICR mice strain, in which the mice were administrated with a single oral or intravenous dose (400 mg/kg with 7.1 mg/kg of scopoletin and tomentin in mixture and 34.6 mg/kg of sphaeralcic acid) of the SaTSS standardized active fraction. The results of the validated analytical methods allowed establishing, in a validated manner, that a coumarin mixture and sphaeralcic acid present in the SaTES fraction were detected in plasma. According to the values of Akaike Information Criteria (AIC), Sum of Squares (SS), Schwarz Criteria (SC), and by the determination coefficient (R2), the compounds follow a two-compartment model.

Harnessing PET to track micro- and nanoplastics in vivo

The proliferation of plastics in the environment continues at an alarming rate. Plastic particles have been found to be persistent and ubiquitous pollutants in a variety of environments, including sea water, fresh water, soil, and air. In light of this phenomenon, the scientific and medical communities have become increasingly wary of the dangers posed to human health by chronic exposure to microplastics (< 5 mm diameter) and nanoplastics (< 100 nm diameter). A critical component of the study of the health effects of these pollutants is the accurate determination of their pharmacokinetic behavior in vivo. Herein, we report the first use of molecular imaging to track polystyrene (PS) micro- and nanoplastic particles in mammals. To this end, we have modified PS particles of several sizes—diameters of 20 nm, 220 nm, 1 µm, and 6 µm—with the chelator desferrioxamine (DFO) and radiolabeled these DFO-bearing particles with the positron-emitting radiometal zirconium-89 (89Zr; t1/2 ~ 3.3 d). Subsequently, positron emission tomography (PET) was used to visualize the biodistribution of these radioplastics in C57BL/6J mice at 6, 12, 24, and 48 h after ingestion. The imaging data reveal that the majority of the radioplastics remain in the gastrointestinal tract and are eliminated through the feces by 48 h post-ingestion, a result reinforced by acute biodistribution studies. Ultimately, this work suggests that nuclear imaging—and PET in particular—can be a sensitive and effective tool in the urgent and rapidly growing effort to study the in vivo behavior and potential toxicity of micro- and nanoplastics.

Investigating the Potential of Transdermal Delivery of Avanafil Using Vitamin E-TPGS Based Mixed Micelles Loaded Films

To avoid the first-pass metabolism of avanafil (AVA) and its altered absorption in the presence of food after oral administration, this study aimed to investigate the potential of TPGS-based mixed micelle (MM)-loaded film for transdermal delivery and the enhancement of bioavailability. A Box–Behnken design was employed to optimize the permeation behavior of AVA from the transdermal film across the skin. The variables were the hydrophile-lipophile balance (HLB) of the surfactant (X1), the concentration of mixed micelles (MMs) in the film (X2), and the concentration of the permeation enhancer (X3). The initial permeation of AVA after 1 h (Y1), and the cumulative permeation of AVA after 24 h (Y2) were the dependent variables. Ex vivo studies were carried out on freshly isolated rat skin to investigate the drug’s permeation potential and results were visualized using a fluorescence laser microscope. Moreover, the pharmacokinetic behavior after a single application on male Wistar rats, in comparison with films loaded with raw AVA, was evaluated. The results showed that the optimum factor levels were 9.4% for the HLB of the surfactant used, and 5.12% MMs and 2.99% penetration enhancer in the film. Imaging with a fluorescence laser microscope indicated the ability of the optimized film to deliver the payload to deeper skin layers. Furthermore, optimized AVA-loaded TPGS-micelles film showed a significant increase (p < 0.05) in the Cmax of AVA and the area under the AVA plasma curve (approximately three-fold). The optimized AVA-loaded TPGS-MM film thus represents a successful delivery system for enhancing the bioavailability of AVA.