Safety and Pharmacokinetics in Human Volunteers of Taniborbactam (VNRX-5133), a Novel Intravenous β-Lactamase Inhibitor

Taniborbactam (formerly VNRX-5133), an investigational β-lactamase inhibitor active against both serine- and metallo-β-lactamases, is being developed in combination with cefepime to treat serious infections caused by multidrug-resistant gram-negative bacteria. This first-in-human study evaluated the safety and pharmacokinetics of single and multiple doses of taniborbactam in healthy adult subjects. Single doses of 62.5 to 1500 mg taniborbactam and multiple doses of 250 to 750 mg taniborbactam every 8 hours (q8h) for 10 days were examined; all taniborbactam doses were administered as a 2-hour intravenous infusion. No subjects experienced serious adverse events or discontinued treatment due to adverse events. The most common adverse event in both placebo and taniborbactam treated subjects was headache. The pharmacokinetics of taniborbactam were similar to the pharmacokinetics reported for cefepime. Taniborbactam demonstrated dose-proportional pharmacokinetics with low intersubject variability. Following single doses and with extended sampling, the mean terminal elimination half-life ranged from 3.4 to 5.8 hours, however the majority of exposure was characterized by an earlier phase with a half-life of about 2 hours. Following multiple dosing there was minimal accumulation of taniborbactam in plasma. At steady-state, approximately 90% of the administered dose of taniborbactam was recovered in urine as intact drug. There was no appreciable metabolism observed in either plasma or urine samples. (This study is registered at clinicaltrials.gov as NCT02955459.)

Bioanalysis in the Age of New Drug Modalities

In the absence of regulatory guidelines for the bioanalysis of new drug modalities, many of which contain multiple functional domains, bioanalytical strategies have been carefully designed to characterize the intact drug and each functional domain in terms of quantity, functionality, biotransformation, and immunogenicity. The present review focuses on the bioanalytical challenges and considerations for RNA-based drugs, bispecific antibodies and multi-domain protein therapeutics, prodrugs, gene and cell therapies, and fusion proteins. Methods ranging from the conventional ligand binding assays and liquid chromatography-mass spectrometry assays to quantitative polymerase chain reaction or flow cytometry often used for oligonucleotides and cell and gene therapies are discussed. Best practices for method selection and validation are proposed as well as a future perspective to address the bioanalytical needs of complex modalities.

Stability-indicating UHPLC and TLC-densitometric Methods for the Determination of Tiamulin Fumarate

Two novel stability-indicating methods were developed for the determination of tiamulin fumarate. in the presence of its degradation products. The first was UHPLC-UV method. Efficient separation was achieved by isocratic elution with a mobile phase of 0.1% aqueous ortho-phosphoric acid (pH 3.5 ± 0.5) and methanol (20:80, v/v) with UV detection at 210 nm. Linearity was obtained in the range of 0.5-10.0 µg mL-1 with mean accuracy of 100.40 ± 0.71. The second method was a TLC-densitometric evaluation of a thin-layer chromatogram of the intact drug using a mobile phase of methanol: pentanol: ethyl acetate: 16.5% ammonia (5:4:2:4, by volume). The TLC-plates were scanned densitometrically at 220 nm where Rf values were 0.58, 0.48 and 0.74 for tiamulin F, its acidic and oxidative degradants, respectively. Moreover, the plates were sprayed with 16% sulfuric acid, heated at 105°C for 10 min. where a yellow-coloured band appeared corresponding to the intact drug was scanned densitometrically at 450 nm. While the bands of the two degradants were no longer observed anymore. Tiamulin F was determined in the range of 1.0-10.0 μg/band with mean accuracy of 100.27% ± 1.47 at 220 nm and 99.93% ± 1.38 at 450 nm. The proposed methods were successfully applied for the determination of drug in marketed oral solution. The obtained results were statistically analyzed and found to be in accordance with those obtained by a reported method.

Chemical Degradation of Intravenous Chemotherapy Agents and Opioids by a Novel Instrument

Purpose: To assess chemical degradation of various liquid chemotherapy and opioid drugs in the novel RxDestruct™ instrument. Methods: Intravenous (IV) drug solutions for chemotherapy and pain management were prepared using 0.9% normal saline in Excel® bags to a final volume of 500 mL. We investigated duplicate IV solutions of methotrexate (0.1 mg/mL), etoposide (0.4 mg/mL), doxorubicin (0.25 mg/mL), cladribine (12.4 µg/mL), fentanyl (1.0 µg/mL), and hydromorphone (12.0 µg/mL) in this study. Solutions were poured into an automated instrument to undergo pulsatile chemical treatment (Fenton reactions) for 20 minutes, and then discharged from the instrument through a waste outlet. Extent of intact drug degradation was determined by measuring concentrations of drugs before entry into the instrument and after chemical treatment in the filtrate using high-performance liquid-chromatography with ultraviolet detection (HPLC-UV). Results: Following chemical reactions (Fenton processes) in the automated instrument, infusion solutions containing methotrexate, etoposide, doxorubicin, and cladribine had levels below the HPLC-UV limit of quantification (LOQ), indicating <50 ppb of each. This equated to >99.5%, 99.99%, 99.9%, and 99.8% intact drug loss, respectively. Likewise, processed samples of fentanyl and hydromorphone contained levels below the LOQ (78 and 98 ng/mL, respectively), indicating extensive degradation (>92.2% and 99.2% intact drug loss, respectively). Conclusion: The novel instrument was capable of degrading intact chemotherapy and opioid drugs prepared in infusion solutions to undetectable quantities by HPLC-UV. RxDestruct™ is a possible alternative for disposal of aqueous medication waste.

Stability-Indicating Chromatographic Methods for the Investigation of Ritodrine Hydrochloride Stability and Characterization of the Oxidative Degradation Product

Two simple and sensitive chromatographic methods were developed and validated for quantitative determination of ritodrine hydrochloride in presence of its oxidative degradation product. The first method depends on densitomeric determination of thin-layer chromatograms of the intact drug in presence of its oxidative degradate. Excellent separation was achieved at 220 nm using a mobile phase of dichloromethane–methanol–glacial acetic acid (15 : 5 : 0.25, v/v/v). The second was an HPLC method, in which efficient separation was carried out on C18 column (150 × 4.6 × 5 μm) using a mobile phase consisting of water: acetonitrile (70,30, v/v) at a flow rate of 1 mL min−1 and UV detection at 220 nm. Beer’s law was obeyed in the range of 0.025–0.3 μg/spot and 5–40 μg mL−1 of the intact drug using the two methods, respectively. The proposed methods were validated according to International Conference on Harmonization guidelines and successfully applied for the determination of ritodrine hydrochloride in bulk powder, laboratory prepared mixtures and pharmaceutical dosage form with good accuracy and precision. The results obtained were compared with those of the reported method and were found to be in good agreement.

STABILITY-INDICATING METHODS FOR THE DERTERMINATION OF GEMIFLOXACIN IN PRESENCE OF ITS ACID DEGRADATION PRODUCT(S)

Brilliant, valid and simple five UV spectrophotometric stability indicating techniques are adopted for the determination of Gemifloxacin (GEM) in presence of its acid degradation products over a concentration range of 2-12 μg mL-1. The first method is an application of the first derivative (1D) spectrophotometry, that allows the determination of GEM without interference of its acid degradation products at zero crossing wavelength (254.6 nm). The second method depends on the first-derivative of the ratio spectra spectrophotometry (1DD) for determination of GEM in presence of its acid degradation products at a maximum of 273.0 nm and a minimum of 284.0 nm, While the third dual wavelength method offers a superior stability indicating procedures for the determination of GEM in the zero order spectra at the wavelength pair of 271.8 nm and 325.0 nm. The fourth method is the ratio difference one, with the advantages of minimal data processing and wide range of application. It is applied for the analysis of intact drug in presence of its acid degradation products by measuring the difference in the peak amplitude at the ratio spectra at 355.0 nm and 270.0 nm. The last method is based on the quantification of GEM through the bivariate calibration at 255.0 nm and 277.0 nm by adopting simple mathematic algorithm that provides simplicity and rapidity.

Microsized Graphite Sensors for Potentiometric Determination of Cyclobenzaprine Hydrochloride in Pure Powder, Tablets, and Plasma

Two cyclobenzaprine hydrochloride (CZ) microsized graphite selective sensors were investigated with dibutylsebacate as a plasticizer in a polymeric matrix of carboxylated polyvinyl chloride (PVC-COOH) in the case of sensor 1, based on the interaction between the drug and the dissociated COOH groups in the PVC-COOH. Sensor 2 was based on the interaction between the drug and ammonium reineckate, which acted as anionic electroactive material in the presence of polyvinyl chloride matrix. The two sensors were constructed by using 2-hydroxy propyl β-cyclodextrin as an ionophore, which has a significant influence on increasing the membrane sensitivity and selectivity of both sensors. Fast and stable Nernstian responses of 1 × 10–5–1 × 10–2 and 1 × 10m–4–1 × 10–2 M for the two sensors, respectively, with slopes of 58.6 and 55.5 mV/decade, respectively, over the pH range 2–4 were obtained. The proposed method displayed useful analytical characteristics for determination of CZ in its pure powder form with average recoveries 99.95 ± 0.23 and 99.61 ± 0.34% for sensors 1 and 2, respectively, and in plasma with good recoveries. The sensors were also used to determine the intact drug in the presence of its degradate and, thus, could be used as stability-indicating methods. The obtained results by the proposed methods were statistically analyzed and compared with those obtained by the U.S. Pharmacopeia method; no significant difference for either accuracy or precision was observed. Results obtained with the two electrodes revealed their performance characteristics, which were evaluated according to International Union of Pure and Applied Chemistry recommendations.

Membrane Electrodes for the Determination of Pyridostigmine Bromide

Two pyridostigmine bromide (PB) selective electrodes were investigated with 2-nitrophenyl octyl ether as a plasticizer in a polymeric matrix of carboxylated polyvinyl chloride (PVC-COOH), based on the interaction between the drug solution and the dissociated COOH groups in the PVC-COOH. One of the sensors was fabricated by using PVC-COOH only as anionic site without incorporation of an ionophore (sensor 1). The second sensor was constructed by using 2-hydroxy propyl -cyclodextrin as an ionophore (sensor 2). Linear responses of PB within a concentration range of 103102 and 105102 M, with slopes of 51.9 0.31 and 56.7 0.40 mV/decade over pH range of 510 were obtained using sensors 2 and 1, respectively. The proposed method displayed useful analytical characteristics for determination of PB in tablets with average recoveries of 100.22 0.62, and 100.15 0.72, and in plasma with average recoveries of 99.14 1.19 and 99.79 0.72, for sensors 2 and 1, respectively. The utility of 2-hydroxy propyl -cyclodextrin as an ionophore has a significant influence on increasing both membrane sensitivity and selectivity of sensor 2 in comparison with sensor 1. The methods were also used to determine the intact drug in the presence of its degradate, and thus could be used as stability-indicating methods. The results obtained by the proposed procedures were statistically analyzed and compared with those obtained by the U.S. Pharmacopeia method. No significant difference for either accuracy or precision was observed.