Removal of Remdesivir's Metabolite GS-441524 by Hemodialysis in a Double Lung Transplant Recipient with COVID-19.

Remdesivir has reported efficacy against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in vitro and in vivo Drug-drug interactions limit therapeutic options in transplant patients. Remdesivir and its metabolite GS-441524 are excreted principally in urine. In intensive care unit (ICU) settings, in which multiple-organ dysfunctions can occur rapidly, hemodialysis may be a viable option for maintaining remdesivir treatment, while improving tolerance, by removing both remdesivir's metabolite (GS-441524) and sulfobutylether ß-cyclodextrin sodium (SEBCD). Additional studies may prove informative, particularly in the evaluations of therapeutic options for coronavirus disease 2019 (COVID-19).

Supramolecular Complexation in Biological Media: NMR Study on Inclusion of an Anionic Tetraarylporphyrin into a Per-O-Methylated ß-Cyclodextrin Cavity in Serum, Blood, and Urine.

The supramolecular complexation of 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (TPPS) with heptakis(2,3,6-tri-O-methyl)-ß-cyclodextrin (TMCD) has been known to be highly specific in aqueous media. In this study, we have used NMR spectroscopy to reveal that this supramolecular system also works even in biologically crowded media such as serum, blood, and urine. A 13 C-labeled heptakis(2,3,6-tri-O-methyl-13 C)-ß-cyclodextrin (13 C-TMCD) was synthesized and studied using one-dimensional (1D) HMQC spectroscopy in serum and blood. The 1D HMQC spectrum of 13 C-TMCD showed clear signals due to the 2-, 3-, and 6-O13 CH3 groups, whose chemical shifts changed upon addition of TPPS due to quantitative formation of the 13 C-TMCD/TPPS=2/1 inclusion complex in such biological media. The 1 H NMR signals of non-isotope-labeled TPPS included by 13 C-TMCD were detected using the 13 C-filtered ROESY technique. A pharmacokinetic study of 13 C-TMCD and its complex with TPPS was carried out in mice using the 1D HMQC method. The results indicated that (1) 1D HMQC is an effective technique for monitoring the inclusion phenomena of 13 C-labeled cyclodextrin in biological media and (2) the intermolecular interaction between 13 C-TMCD and TPPS is highly selective even in contaminated media like blood, serum, and urine.

Clinical Pharmacokinetics of Sulfobutylether-ß-Cyclodextrin in Patients With Varying Degrees of Renal Impairment.

Delafloxacin, a fluoroquinolone, has activity against Gram-positive organisms including methicillin-resistant S aureus and fluoroquinolone-susceptible and -resistant Gram-negative organisms. The intravenous formulation of delafloxacin contains the excipient sulfobutylether-ß-cyclodextrin (SBECD), which is eliminated by renal filtration. This study examined the pharmacokinetics and safety of SBECD after single intravenous (IV) infusions in subjects with renal impairment. The study was an open-label, parallel-group, crossover study in subjects with normal renal function or mild, moderate, or severe renal impairment, and those with end-stage renal disease undergoing hemodialysis. Subjects received 300 mg delafloxacin IV or placebo IV, containing 2400 mg SBECD, in 2 periods separated by ≥14-day washouts. SBECD total clearance decreased with decreasing renal function, with a corresponding increase in area under the concentration-time curve (AUC0-∞ ). After IV delafloxacin 300 mg administration, SBECD mean total clearance was 6.28 and 1.24 L/h, mean AUC0-∞ was 387 and 2130 h·µg/mL, and mean renal clearance was 5.36 and 1.14 L/h in normal and severe renal subjects, respectively. Similar values were obtained after IV placebo administration. In subjects with end-stage renal disease, delafloxacin 300 mg IV produced mean SBECD AUC0-48 values of 2715 and 7861 h·µg/mL when dosed before and after hemodialysis, respectively. Total SBECD clearance exhibited linear relationships to estimated glomerular filtration rate and creatinine clearance. Single doses of IV delafloxacin 300 mg and IV placebo were well tolerated in all groups. In conclusion, decreasing renal function causes reduced SBECD clearance and increased exposures, but SBECD continues to exhibit a good safety and tolerability profile in IV formulations.

Comparison in toxicity and solubilizing capacity of hydroxypropyl-ß-cyclodextrin with different degree of substitution.

Hydroxypropyl-ß-cyclodextrin (HP-ß-CD) has been widely used as an effective solubilizing agent in pharmaceutical industry for many years. However, the effect of degree of substitution (D.S.) of HP-ß-CD on solubilizing capacity and toxicity has not been concerned. In this study, solubilizing capacity of HP-ß-CDs with three different D.S. (4.55, 6.16 and 7.76) for 16 drugs were measured and their toxicities were compared by a 7-day i.v. administration (q.d.) study in rats. Generally, HP-ß-CD with high D.S. (7.76) showed weaker solubilizing capacity for steroids and BCS class II drugs, but lower hemolytic activity, compared with that of HP-ß-CD with low (4.55) or medium (6.16) D.S. HP-ß-CD with low D.S. resulted in more changes in hematological and biochemical parameters, but the effects were reversible after a 7-day recovery. Moreover, HP-ß-CD with medium D.S. may have slightly greater nephrotoxicity than the other two HP-ß-CDs. HP-ß-CDs with different D.S. had similar urine excretion percentage after i.v. administration and none of them was found to affect glomerular filtration function of rats. The results suggest that HP-ß-CD with low D.S. would be a better choice considering both the solubilizing capacity and toxicity. However, comparison in toxicity of HP-ß-CDs with different D.S. should be carried out in human in view of its species-dependence property.

Evaluation of the impact of sulfobutylether7 -ß-cyclodextrin on the liquid chromatography-mass spectrometry analysis of biological samples arising from in vivo pharmacokinetic studies.

The utility of cyclodextrin (CD) complexation in improving apparent solubility of drugs in parenteral formulations is well established. Administration of these formulations delivers CD directly into the systemic circulation, and it may be necessary to demonstrate unaltered in vivo disposition of a drug coadministered with a CD. Crucial to the undertaking of such a study is the need for bioanalytical assays in which CD presence does not impact drug quantitation. This is of particular importance when assessing the potential impact of in vivo CD complexation on the urinary excretion of a drug, as CDs are predominantly eliminated via glomerular filtration, and hence are present in urine at significantly higher concentration than would be present in blood and plasma. Of 23 publications (in the past 30 years) describing preclinical and clinical assessment of drug pharmacokinetics after i.v. administration of CD-enabled formulations, only two reports clearly stated that the presence of CD had no impact on assay performance. In this work, we describe the simple process involved in (1) predicting the maximum concentrations of a modified CD, sulfobutylether7 -ß-CD (SBE7 -ß-CD), in plasma and urine samples from preclinical studies, and (2) evaluating the impact of SBE7 -ß-CD on the quantitative liquid chromatography-mass spectrometry analysis of rimantadine.

Inclusion complex-based solid-phase extraction of steroidal compounds with entrapped beta-cyclodextrin polymer.

Although the hydrophobic interaction-based solid-phase extraction (SPE) has been widely used, the extraction yields of steroids including androgens, estrogens, and corticoids were slightly different along with the physical and chemical properties of each molecule. A new SPE technique based on the formation of an inclusion complex with beta-cyclodextrin (betaCD) has been achieved for comprehensive sample purification in mass spectrometric analysis of 45 endogenous or synthetic androgens, 11 endogenous estrogens, and 21 corticoids. A copolymer of betaCD with epichlorohydrin was prepared by a cross-linking reaction followed by entrapment with 0.3M CaCl(2) to yield an improved SPE sorbent and the hydrolyzed urine samples were applied for purification. Steroidal compounds tested on the entrapped betaCD polymer were extracted with tetrahydrofuran and the overall recoveries ranged from 82% to 112% for 77 steroids in urine. Especially, the hydroxylated estrogens showed an excellent binding capacity (96-116% recovery) to betaCD through hydrogen bonding between their phenolic hydroxyl and exterior hydroxyl groups. A comparison between SPE methods with betaCD and Oasis HLB as a conventional cartridge showed that the extraction efficiency of polar steroids was significantly increased in the betaCD experiment, which has no connection with different polarity of steroid molecules. Due to its multi-functional mechanism derived from molecular inclusion and chemical interactions, this new SPE sorbent resulted in better selectivity and extraction efficiency than that obtained using the conventionally used hydrophobicity-based SPE method.

Metabonomics study on the effects of the ginsenoside Rg3 in a beta-cyclodextrin-based formulation on tumor-bearing rats by a fully automatic hydrophilic interaction/reversed-phase column-switching HPLC-ESI-MS approach.

The goal of this study was the application of a novel, fully automatic column-switching approach in a metabonomics study combining the orthogonal selectivities of hydrophilic interaction chromatography (HILIC) and reversed-phase chromatography. The temporal, pharmacodynamic effects of the ginsenoside Rg3 on the metabonome in urine of healthy and liver-tumor-bearing rats have been investigated. Within a total analysis time of 52 min we detected 5686 polar, and on the second column an additional 1808 apolar, urinary metabolite ions. The administration of a single, high dose of Rg3 in a beta-cyclodextrin-based formulation led to a considerable change of the metabolic pattern in cancer rats during 3 days studied. Seventeen biomarker candidates including three apolar metabolites, which were not retained on the HILIC column, were detected. Overall, the results suggest that the developed liquid chromatography-mass spectrometry strategy is a promising tool in metabonomics studies for global analysis of highly complex biosamples. It may not only increase the number of discovered biomarkers but consequently improve the comprehensive information on metabolic changes in a fully automatic manner.

Selective and sensitive hydroxypropyl-beta-cyclodextrin based sensor for simple monitoring of (+)-catechin in some commercial drinks and biological fluids.

(+)-Catechin (CAT) was considered as a polyphenolic compound abundantly contained in plants. It exerts protective effect against cancer, inflammatory and cardiovascular diseases. These protective effects are mainly attributed to its antioxidative activity by scavenging free radicals. Therefore, the need of simple, selective and sensitive monitoring of (+)-catechin in commercial drinks and biological fluids is crucial. A new selective and sensitive voltammetric quantification of (+)-catechin was investigated at low cost hydroxypropyl-beta-cyclodextrin modified carbon paste sensor in acidic solutions. The constructed sensor was treated in simple and fast manner to increase its stability for catechin determination. The effect of solution and instrumental parameters was investigated by using osteryoung square-wave anodic voltammetry (OSWAV) at pH 2.20 and differential pulse cathodic voltammetry (DPCV) at pH 4.40 in 0.10 M Britton-Robinson buffer. Acidic solutions were chosen to increase the stability of (+)-catechin, reduce its adsorption on the sensor surface and increase the selectivity of proposed method. Cyclic voltammetry (CV) was used to elucidate the electrochemical mechanism of catechin at the modified electrochemical sensor. A linear range up to 7.20 and 4.20 microg mL(-1) of catechin was achieved in anodic and cathodic voltammetry, respectively. The method gave reproducible and reliable results with 1.50 g mL(-1) catechin (S.D. 0.062). Limit of detection of 0.12 and 0.30 ng mL(-1) and limit of quantification (LOQ) of 1.10 and 2.80 ng mL(-1) were easily achieved using anodic and cathodic voltammetry, respectively. Selectivity of the proposed procedure was estimated by testing recovery and adding the most interfering metal ions and/or organic compounds. The proposed method was applied successfully to selective determination of catechin in some commercial drinks like tea, cocoa and coffee with acceptable recovery range (98-102%). The extraction of catechin was rather simple, making it suitable for studies with a large number of commercial samples. Furthermore, the application to urine samples without pretreatment was achieved and statistically confirmed at 95% confidence level. It was easy to analyze catechin in urine down to 0.55 ng mL(-1).