A novel LC-MS/MS approach to the pharmacokinetic study of free and bound aflibercept simultaneously

Comprehensive characterization of Epimedium-Rhizoma drynariae herb pair in rat plasma, urine, and feces metabolic profiles by UHPLC-Q-Orbitrap HRMS combined with diagnostic extraction strategy and multicomponent pharmacokinetic study by UHPLC-MS/MS

Epimedium-Rhizoma drynariae (EP-RD) was a well-known herb commonly used to treat bone diseases in traditional Chinese medicine. Nevertheless, there was incomplete pharmacokinetic behavior, metabolic conversion and chemical characterization of EP-RD in vivo. Therefore, this study aimed to establish metabolic profiles combined with multicomponent pharmacokinetics to reveal the in vivo behavior of EP-RD. Firstly, the diagnostic product ions (DPIs) and neutral losses (NLs) filtering strategy combined with UHPLC-Q-Orbitrap HRMS for the in vitro chemical composition of EP-RD and metabolic profiles of plasma, urine, and feces after oral administration of EP-RD to rats were proposed to comprehensively characterize the 47 chemical compounds and the 97 exogenous in vivo (35 prototypes and 62 metabolites), and possible biotransformation pathways of EP-RD were proposed, which included phase I reactions such as hydrolysis, hydrogenation, dehydrogenation, hydroxylation, dehydroxylation, isomerization, and demethylation and phase II reactions such as glucuronidation, acetylation, methylation, and sulfation. Moreover, a UHPLC-MS/MS quantitative approach was established for the pharmacokinetic analysis of seven active components: magnoflorine, epimedin A, epimedin B, epimedin C, icariin, baohuoside II, and icariin II. Results indicated that the established method was reliably used for the quantitative study of plasma active ingredients after oral administration of EP-RD in rats. Compared to oral EP alone, the increase in area under curves and maximum plasma drug concentration (P < 0.05). This study increased the understanding of the material basis and biotransformation profiles of EP-RD in vivo, which was of great significance in exploring the pharmacological effects of EP-RD.

Study on the Effects of Different anti-VEGF drugs on Fibrovascular Membranes of Proliferative Diabetic Retinopathy

PURPOSE

To investigate the effects of different anti-VEGF drugs on fibrovascular membranes (FVM) in proliferative diabetic retinopathy (PDR). In addition, in vitro model was used to simulate the intraocular fibroblasts barrier to explore the penetration of different anti-VEGF drugs.

METHODS

24 eyes from 24 PDR patients with FVM were recruited for this prospective observational study. The patients were randomized to receive one of three anti-VEGF drugs (Ranibizumab, Conbercept, or Aflibercept). Then neovascular structures were assessed by optical coherence tomography angiography (OCTA) before intravitreal injection (pre-IVT) and 1, 2, and 3 days after intravitreal injection (post-IVT). The changes in vessels area (VSA), vessels percentage area (VPA), junction density (JD), and average lacunarity (AL) were analyzed by using the image processing software Angiotool. In vitro penetrating model with fibroblasts barrier was used to compare the effects of the three drugs on human retinal vascular endothelial cells (HRVECs) over 3 days by Cell proliferation measurement. Moreover, the drug concentrations in the penetrating model were detected by liquid chromatography-mass spectrometry (LC-MS).

RESULTS

The VSA, VPA, and JD all decreased, while the AL increased in Ranibizumab group(n=8), Conbercept group (n=8), and Aflibercept group (n=8) within 3 days (P<0.05). Meanwhile, under the condition of the same amount of substance, the inhibition effect of Ranibizumab on HRVEC was the strongest in the penetrating model evaluated by CCK8 absorbance experiments of HRVECs (F_CCK8=6.493, P_CCK8= 0.0051), and the number of transmembrane molecules in the Ranibizumab group was also the largest within 3 days (F=8.209, P=0.0006) among the three groups.

CONCLUSION

Angiotool is feasible to reconstruct the neovascular structure on the FVM in OCTA images. The three different anti-VEGF drugs can significantly reduce the vascular area and density on the proliferating membranes, and there is no significant difference in the anti-neovascularization among the three drugs clinically. However, small molecule drug is more penetrating and move faster across membranes in vitro cell model.

CLINICAL TRIAL REGISTRATION

This trial is registered with the Chinese Clinical Trial Registry (http://www.chictr.org.cn, registration number ChiCTR2300067476).

Microvolume Analysis of Aflibercept in Aqueous Humor Using Mass Spectrometry

Purpose

To develop a microvolume analytical method for measurement of the aflibercept concentration in human intraocular fluid and plasma.

Methods

We analyzed trace amounts of aflibercept in human aqueous humor using Fab-selective proteolysis and nano-surface and molecular-orientation limited (nSMOL) proteolysis, coupled with liquid chromatography–tandem mass spectrometry (LC-MS/MS). Patients with age-related macular degeneration or diabetic macular edema were recruited. Just after an injection of 50 µL of aflibercept, regurgitate from needle holes was collected with a micropipette pressed to the side of the injection hole within 10 seconds. The median amount of regurgitate was 4 µL (range, 1–18 µL).

Results

In human plasma, the aflibercept concentration ranged between 0.195 and 50 µg/mL when using the quantitative signature peptide IIWDSR (aa. 56–61) present on the vascular endothelial growth factor receptor 1 domain of aflibercept. The method was validated by evaluating its linearity, carryover, selectivity, accuracy and precision, dilution effect, and sample/processing stability. As only a minimal amount of regurgitate through needle holes can be sampled, we performed and verified the aflibercept assay using patient samples after 1:10 dilution with control human plasma, a recognized diluent. The median concentration of aflibercept in the regurgitate was 240 µg/mL (range, 13–4300 µg/mL).

Conclusions

Our findings indicate that the aflibercept assay using human intraocular fluid can be reliably performed using nSMOL coupled with LC-MS/MS.

Translational Relevance

This technique for quantifying aflibercept in the regurgitate suggests that the amount of drug lost post-injection can be ignored, even in patients with a relatively large leak after vitreous injection. This new methodology suggests possible therapeutic responses and may be employed as a general analytical method for trapping many biologics, such as vascular endothelial growth factor, in various types of clinical samples, unaffected by proteinaceous or small organic pharmaceuticals.

A rapid and universal liquid chromatograph-mass spectrometry-based platform, refmAb-Q nSMOL, for monitoring monoclonal antibody therapeutics

Accurate multiplexed quantitation of unique signature peptides derived from monoclonal antibody therapeutics with a universal reference antibody refmAb-Q using Fab-selective proteolysis nSMOL coupled with LC-MS/MS.