Development and validation of samples stabilization strategy and LC-MS/MS method for simultaneous determination of clevidipine and its primary metabolite in human plasma: Application to clinical pharmacokinetic study in Chinese healthy volunteers

LC-MS/MS method for dual-ligand peptide-drug CBP-1018 and its deconjugated payload MMAE including sample stabilization strategy for its MC-Val-Cit-PABC linker

Recently, peptide-drug conjugate (PDC) has become the most promising conjugated drug for tumor therapy after antibody-drug conjugate due to stronger tumor penetration capacity and lower immunogenicity. CBP-1018 was a PDC with dual-ligand conjugated to MMAE via a cleavable linker (MC-Val-Cit-PABC) that can be lysed by cathepsins B. In this study, two specific LC-MS/MS methods were developed and validated for the determination of CBP-1018 and its metabolite MMAE in human plasma. To prevent the cleavable MC-Val-Cit-PABC linker from degradation, a protease inhibitor (cOmplete solution) was added to the pre-cooled vacuum tubes and the separated plasma samples. The assays involved the pretreatment of CBP-1018 by protein precipitation with H2O-ACN (1:9, v/v) and the extraction of MMAE by liquid-liquid extraction with ethyl acetate under alkaline condition to eliminate the interference of CBP-1018 on MMAE. The two analytes showed good linearities over the calibration ranges (R2 ≥ 9980). Both accuracy and precision met the acceptance criteria. The validated methods were successfully applied to the phase I dose-escalation study of CBP-1018 injection in Chinese patients with solid tumors to evaluate the pharmacokinetic properties of CBP-1018 and MMAE. The results showed that CBP-1018 was eliminated immediately after injection and MMAE reached the maximum exposure at approximately 2 h after infusion. The maximum concentration of MMAE did not exceed 20.0 ng/mL, suggesting that the off-target toxicity of CBP-1018 injection was controllable.

Pharmacokinetic study of Tdp1 inhibitor resulted in a significant increase in antitumor effect in the treatment of Lewis lung carcinoma in mice by its combination with topotecan

We have previously shown that the Tdp1 inhibitor, enamine derivative of usnic acid, the agent OL9-116, enhances the antitumor activity of topotecan. In the present study, we developed and validated LC-MS/MS method for the quantification of OL9-116 in mouse whole blood and studied pharmacokinetics of the agent. The substance OL9-116 was shown to be stable in the whole blood in vitro. Sample preparation included two steps: mixing 10 µL of a blood sample with 10 µL of 0.2 M ZnSO4 aqueous solution, followed by protein precipitation with 100 µL of acetonitrile containing internal standard. Quantification of the compound was performed using SCIEX 6500 QTRAP mass spectrometer in MRM mode following chromatographic separation on a C8 reversed-phase column. The method was validated in terms of selectivity, linearity, accuracy, precision, recovery, and stability of the prepared sample. When the agent OL9-116 was administered intragastrically at a dose of 150 mg/kg, the maximum concentration in the blood (about 5000 ng/mL) was reached after 2-4 h followed by the distribution and elimination of the compound. A study of the antitumor activity of a combination of OL9-116 and topotecan against Lewis lung carcinoma revealed that administration of topotecan 3 h after OL9-116 resulted in the most pronounced antitumor effect compared to simultaneous or individual administration of both compounds.

Synthesis of N-heterocyclic amides based on (+)-camphoric acid and study of their antiviral activity and pharmacokinetics

Efficient conditions for the synthesis of nitrogen-containing heterocyclic derivatives of (1R,3S)(+)-camphoric acid were selected. A series of heterocyclic compounds based on (+)-camphoric acid bearing pharmacophoric fragments was synthesized using the developed methodology. The compounds were tested for their antiviral activity against SARS-CoV-2 and H1N1 influenza viruses, and efficient inhibitors were identified that are of significant interest for further studies. The stability of the compounds and pharmaco-kinetics of the leader compound were studied when administered intragastrically and intramuscularly to mice at a dose of 200 mg kg^-1 using the HPLC-MS/MS method.

Simultaneous Quantitation of Clevidipine and Its Active Metabolite H152/81 in Human Whole Blood by LC-MS/MS: Application to Bioequivalence Study

Clevidipine is an ultrashort-acting dihydropyridine calcium antagonist, which can control blood pressure accurately. It is necessary to develop a liquid chromatography–tandem mass spectrometry (LC-MS/MS) method to quantitate clevidipine and its active metabolite H152/81 for clinical pharmacokinetic study and therapeutic drug monitoring. Liquid–liquid extraction was used for sample preparation, and clevidipine-d7 and H152/81-13C-d3 were chosen as the isotope internal standard. The chromatographic separation was performed on an ACE Excel 2 Phenyl column (50 × 2.1 mm). Mass quantification was carried out on the multiple reaction monitoring of the transitions of m/z 473.1→338.1, 480.1→338.1, 356.0→324.0, and 362.2→326.2 for clevidipine, clevidipine-d7, H152/81, and H152/81-13C-d3. The validated method gave an excellent linearity over a concentration range of 0.1–30 ng/ml for clevidipine and 2–600 ng/ml for H152/81. Other fully validated content such as accuracy, precision, extraction recovery, matrix effect, and stability were also investigated and showed satisfactory results. It was strongly recommended that whole blood is the first choice for clinical bioanalysis. Using whole blood for sample analysis can reduce the whole blood collection volume (1 ml vs. 4 ml) and shorten the time from sample collection to storage to 5 min, and there is no centrifugation process and precooling in the ice water bath, which can further reduce the instability caused by exposure. The method was successfully applied to a bioequivalence study of clevidipine butyrate-injectable emulsion.

The Current Role of Clevidipine in the Management of Hypertension

Acute hypertension, which may damage blood vessels, causes irreversible organ damage to the vasculature, central nervous system, kidney, and heart. Clevidipine, the first third-generation calcium channel antagonist approved by the Food and Drug Administration (FDA) in the past 20 years, is an ultra-short-acting calcium channel blocker that inhibits L-type calcium channels with high clearance and low distribution, can be rapidly metabolized into the corresponding inactive acid, and is rapidly hydrolyzed into inactive metabolites by esterase in arterial blood. Clevidipine is the same as nicardipine in that the main physiological effect is vasodilation and the main target is the arterial system, which has a limited effect on capacitor vessels. Unlike nitroglycerin, clevidipine has a limited effect on preload. In contrast to other direct-acting vasodilators, clevidipine has an ultra-short half-life due to metabolism by nonspecific blood and tissue esterases. Clevidipine trials conducted in adult populations have proven that it can rapidly control blood pressure in cardiac surgery situations and that adverse reactions to clevidipine are similar to those with other antihypertensive agents. In recent years, clinical trials have shown that clevidipine has excellent blood pressure-lowering capability in patients with acute neurological injury (hemorrhage, stroke, and subarachnoid and acute intracerebral hemorrhage), those  undergoing coronary artery bypass graft or spinal surgery, and in those with cerebral aneurysm/pheochromocytoma, acute heart failure, acute aortic syndromes, or renal insufficiency with severe hypertension, and it is equivalent to commonly used blood pressure-lowering medicines such as nicardipine or nitroglycerin. However, there is a lack of large-scale clinical trial data on the efficacy and safety of clevidipine in children during the perioperative period.

Enantiomeric Separation of Dioxopromethazine and its Stereoselective Pharmacokinetics in Rats by HPLC-MS/MS

Dioxopromethazine (DPZ) is a popular phenothiazine antihistamine that is widely used as a racemic drug in clinical to cure respiratory illness. In our work, a reliable, specific, and rapid enantioselective HPLC-MS/MS method has been established and fully validated for the quantification of R- and S-DPZ in rat plasma. After plasma alkalization (with 1 M Na₂CO₃), DPZ enantiomers and diphenhydramine (IS) were extracted using ethyl acetate. Completely separation of R- and S-DPZ (Rs = 2.8) within 12 min was implemented on Chiralpak AGP column (100 × 4.0 mm i.d., 5 μm) employing ammonium acetate (10 mM; pH 4.5) - methanol (90:10, v/v) as mobile phase. Themultiple reaction monitoring (MRM) mode was used for the detection of DPZ enantiomers and IS. The transitions of m/z 317.2 → 86.1 and 256.2 → 167.1 werechosen for monitoring DPZ enantiomers and IS, respectively. Good linearity (r² > 0.995) was achieved for each DPZ enantiomer over the linear ranges of 1.00 - 80.00 ng/mL, with the lower limit of quantitation (LLOQ) of 1.00 ng/mL. The intra-day and inter-day precisions (RSDs,%) were below 12.3%, and accuracies (REs,%) were in the scope of-10.5% to 6.6%, which were within the admissible criteria. The validated bioanalytical approach was applied to the stereoselective pharmacokinetic (PK) research of DPZ in rat plasma for the first time. It was found that significant differences (p < 0.05) exist between the main PK parameters of R- and S-DPZ, indicating the pharmacokinetic behaviors of DPZ enantiomers in rats were stereoselective. The chiral inversion of the enantiomers did not occur during the assay.

Biostability study, quantitation method and preliminary pharmacokinetics of a new antifilovirus agent based on borneol and 3-(piperidin-1-yl)propanoic acid

The stability of the new antifiloviral agent AS-358, which is a derivative of borneol and 3-(piperidin-1-yl)propanoic acid, was studied in the blood and blood plasma of rats in vitro. It was found that both in the blood and in the plasma stabilized by EDTA or heparin, the compound is rapidly hydrolyzed at the ester bond. When sodium fluoride was added to the whole blood, the decomposition of the compound was significantly slowed down, which made it possible to develop and validate a method for the quantitative determination of the agent in this matrix. The method was validated in terms of selectivity, calibration dependence, LLOQ, accuracy and precision, stability in an autosampler, recovery, and carry-over. A 8:2 v/v mixture of methanol containing 2-adamantylamine hydrochloride (internal standard, IS) with 0.2 M aqueous zinc sulfate was used for blood sample treatment and protein precipitation. Analysis was performed by HPLC-MS/MS using reversed phase chromatography. MS/MS detection was performed on a triple quadrupole mass spectrometer 6500 QTRAP (SCIEX) in multiple reaction monitoring (MRM) mode. The transitions 294.5→158.2/98.1 and 152.2→107.2/93.1 were monitored for AS-358 and the IS, respectively. The calibration curve was built in the concentration range of 1-500 ng/mL, the intra-day and inter-day accuracy and precision, carry-over and recovery were within the acceptable limits. The developed method was used for a preliminary study of the pharmacokinetics of the agent AS-358 after its oral administration to rats. It was shown that when the substance was administered at a dose of 200 mg/kg, its concentration in the blood of animals reached 550 ng/mL after 1 h, despite its instability in blood.