Recent advances in the bioanalytical methods of polyethylene glycols and PEGylated pharmaceuticals

Novel strategy for multi-critical quality attributes analysis of pharmaceutical excipient polyethylene glycol by UHPLC-Q-TOF/MS

Polyethylene glycol (PEG) is one kind of polymeric pharmaceutical excipient widely used in pharmaceutics. The critical quality attributes (CQAs) are essential to their physicochemical properties and functions. However, there is no effective strategy to rapidly and simply analyze PEG multi-CQAs. Herein, a novel strategy was developed to simultaneously evaluate four PEG CQAs including average degree of polymerization, average molecular weight, weight-average molecular weight and polydispersity based on comprehensive identification and mathematical models of PEG components. In this strategy, an ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF/MS) method was established and different types and concentrations of mobile phase additives were optimized to overcome the mass discrimination effect of PEG components. MS data was deconvoluted by molecular feature extraction to identify PEG components with multi-charged quasimolecular ions. A total of 168 PEG components were identified in PEG mixture samples. Mathematical models were established based on the logarithmic relation between the degree of polymerization and retention time and a theoretical database including 220 detected and predicted PEG components was constructed to rapidly recognize and identify PEG components in PEG excipients and preparations samples. The calculation formulae for multi-CQAs using UHPLC-Q-TOF/MS analysis results were created, then the strategy workflow to evaluate multi-CQAs was established and validated by PEG standards, showing high efficiency for quality control of PEG excipients and their preparations.

Study on Internal Standards Applicable to the Detection of Recombinant Erythropoietin

With the discovery of the variant c.577del in the EPO gene, the procedure for detecting the presence of recombinant erythropoietin (rEPO) has become complicated and time-consuming. To address this situation, an rEPO confirmation method that uses reverse-normal immunopurification coupled with western blotting (WB) and sodium N-lauroylsarcosinate polyacrylamide gel electrophoresis (SAR-PAGE), which can detect the EPO variant (VAR-EPO) and rEPO with anti-VAR-EPO and anti-EPO antibodies, has been developed. Therefore, it is necessary to develop an internal standard (IS) that can be recognized by an anti-VAR-EPO antibody to monitor reverse immunopurification, ensuring the reliability and accuracy of the analysis. In this study, we constructed an IS based on VAR-EPO modified with polyethylene glycol (PEG) and then assessed its reliability and applicability in doping analysis. The data provided here show that the obtained PEGylated VAR-EPO can be used as an IS to monitor the detection of not only rEPO and VAR-EPO but also EPO receptor agonists in urine samples.

Comparative Validation of Scintillator Materials for X-Ray-Mediated Neuronal Control in the Deep Brain

When exposed to X-rays, scintillators emit visible luminescence. X-ray-mediated optogenetics employs scintillators for remotely activating light-sensitive proteins in biological tissue through X-ray irradiation. This approach offers advantages over traditional optogenetics, allowing for deeper tissue penetration and wireless control. Here, we assessed the short-term safety and efficacy of candidate scintillator materials for neuronal control. Our analyses revealed that lead-free halide scintillators, such as Cs3Cu2I5, exhibited significant cytotoxicity within 24 h and induced neuroinflammatory effects when injected into the mouse brain. In contrast, cerium-doped gadolinium aluminum gallium garnet (Ce:GAGG) nanoparticles showed no detectable cytotoxicity within the same period, and injection into the mouse brain did not lead to observable neuroinflammation over four weeks. Electrophysiological recordings in the cerebral cortex of awake mice showed that X-ray-induced radioluminescence from Ce:GAGG nanoparticles reliably activated 45% of the neuronal population surrounding the implanted particles, a significantly higher activation rate than europium-doped GAGG (Eu:GAGG) microparticles, which activated only 10% of neurons. Furthermore, we established the cell-type specificity of this technique by using Ce:GAGG nanoparticles to selectively stimulate midbrain dopamine neurons. This technique was applied to freely behaving mice, allowing for wireless modulation of place preference behavior mediated by midbrain dopamine neurons. These findings highlight the unique suitability of Ce:GAGG nanoparticles for X-ray-mediated optogenetics. The deep tissue penetration, short-term safety, wireless neuronal control, and cell-type specificity of this system offer exciting possibilities for diverse neuroscience applications and therapeutic interventions.

Hydrodynamic and thermodynamic analysis of PEGylated human serum albumin

Covalent labeling of therapeutic drugs and proteins with polyethylene glycol (PEGylation) is an important modification for improving stability, solubility, and half-life. PEGylation alters protein solution behavior through its impact on thermodynamic nonideality by increasing the excluded volume, and on hydrodynamic nonideality by increasing the frictional drag. To understand PEGylation's impact, we investigated the thermodynamic and hydrodynamic properties of a model system consisting of PEGylated human serum albumin derivatives using analytical ultracentrifugation (AUC) and dynamic light scattering (DLS). We constructed PEGylated human serum albumin derivatives of single, linear 5K, 10K, 20K, and 40K PEG chains and a single branched-chain PEG of 40K (2 × 20K). Sedimentation velocity (SV) experiments were analyzed using SEDANAL direct boundary fitting to extract ideal sedimentation coefficients so, hydrodynamic nonideality ks, and thermodynamic nonideality 2BM1SV terms. These quantities allow the determination of the Stokes radius Rs, the frictional ratio f/fo, and the swollen or entrained volume Vs/v, which measure size, shape, and solvent interaction. We performed sedimentation equilibrium experiments to obtain independent measurements of thermodynamic nonideality 2BM1SE. From DLS measurements, we determined the interaction parameter, kD, the concentration dependence of the apparent diffusion coefficient, D, and from extrapolation of D to c = 0 a second estimate of Rs. Rs values derived from SV and DLS measurements and ensemble model calculations (see complementary study) are then used to show that ks + kD = theoretical 2B22M1. In contrast, experimental BM1 values from SV and sedimentation equilibrium data collectively allow for similar analysis for protein-PEG conjugates and show that ks + kD = 1.02-1.07∗BM1, rather than the widely used ks + kD = 2BM1 developed for hard spheres. The random coil behavior of PEG dominates the colloidal properties of PEG-protein conjugates and exceeds the sum of a random coil and hard-sphere volume due to excess entrained water.

Research progress of prodrugs for the treatment of cerebral ischemia

It is well-known that pharmacotherapy plays a pivotal role in the treatment and prevention of cerebral ischemia. Nevertheless, existing drugs, including numerous natural products, encounter various challenges when applied in cerebral ischemia treatment. These challenges comprise poor brain absorption due to low blood-brain barrier (BBB) permeability, limited water solubility, inadequate bioavailability, poor stability, and rapid metabolism. To address these issues, researchers have turned to prodrug strategies, aiming to mitigate or eliminate the adverse properties of parent drug molecules. In vivo metabolism or enzymatic reactions convert prodrugs into active parent drugs, thereby augmenting BBB permeability, improving bioavailability and stability, and reducing toxicity to normal tissues, ultimately aiming to enhance treatment efficacy and safety. This comprehensive review delves into multiple effective prodrug strategies, providing a detailed description of representative prodrugs developed over the past two decades. It underscores the potential of prodrug approaches to improve the therapeutic outcomes of currently available drugs for cerebral ischemia. The publication of this review serves to enrich current research progress on prodrug strategies for the treatment and prevention of cerebral ischemia. Furthermore, it seeks to offer valuable insights for pharmaceutical chemists in this field, offer guidance for the development of drugs for cerebral ischemia, and provide patients with safer and more effective drug treatment options.

Polyethylene glycol (PEG) as a broad applicability marker for LC-MS/MS-based biodistribution analysis of nanomedicines

Polyethylene glycol (PEG) conjugation (PEGylation) is a well-established strategy to improve the pharmacokinetic and biocompatibility properties of a wide variety of nanomedicines and therapeutic peptides and proteins. This broad use makes PEG an attractive 'allround' candidate marker for the biodistribution of such PEGylated compounds. This paper presents the development of a novel strategy for PEG quantification in biological matrices. The methodology is based on sample hydrolysis which both decomposes the sample matrix and degrades PEGylated analytes to specific molecular fragments more suitable for detection by LC-MS/MS. Method versatility was demonstrated by applying it to a wide variety of PEGylated compounds, including polymeric poly(ethylbutyl cyanoacrylate) (PEBCA) nanoparticles, lipidic nanoparticles (Doxil®, LipImage 815™ and lipid nanoparticles for nucleic acid delivery) and the antibody Cimzia®. Method applicability was assessed by analyzing plasma and tissue samples from a comprehensive drug biodistribution study in rats, of both PEBCA and LipImage 815™ nanoparticles. The results demonstrated the method's utility for biodistribution studies on PEG. Importantly, by using the method described herein in tandem with quantification of nanoparticle payloads, we showed that this approach can provide detailed understanding of various critical aspects of the in vivo behavior of PEGylated nanomedicines, such as drug release and particle stability. Together, the presented results demonstrate the novel method as a robust, versatile and generic approach for biodistribution analysis of PEGylated therapeutics.

A Trojan horse approach for efficient drug delivery in photodynamic therapy: focus on taxanes

Photodynamic therapy is an effective method for the treatment of several types of cancerous and noncancerous diseases. The key to the success of this treatment method is effective drug delivery to the site of action, for instance, a tumor. This ensures not only the high effectiveness of the therapy but also the suppression of side effects. But how to achieve effective targeted delivery? Lately, much attention has been paid to systems based on the so-called Trojan horse model, which is gaining increasing popularity. The principle of this model is that the effective drug is hidden in the internal structure of a nanoparticle, liposome, or nanoemulsion and is released only at the site of action. In this review article, we focus on drugs from the group of mitotic poisons, taxanes, and their use with photosensitizers in combined therapy. Here, we discuss the possibilities of how to improve the paclitaxel and docetaxel bioavailability, as well as their specific targeting for use in combined photo- and chemotherapy. Moreover, we also present the state of the art multifunctional drugs based on cabazitaxel which, owing to a suitable combination with photosensitizers, can be used besides photodynamic therapy and also in photoacoustic imaging or sonodynamic therapy.

Modified Bacteriophage for Tumor Detection and Targeted Therapy

Malignant tumor is one of the leading causes of death in human beings. In recent years, bacteriophages (phages), a natural bacterial virus, have been genetically engineered for use as a probe for the detection of antigens that are highly expressed in tumor cells and as an anti-tumor reagent. Furthermore, phages can also be chemically modified and assembled with a variety of nanoparticles to form a new organic/inorganic composite, thus extending the application of phages in biological detection and tumor therapeutic. This review summarizes the studies on genetically engineered and chemically modified phages in the diagnosis and targeting therapy of tumors in recent years. We discuss the advantages and limitations of modified phages in practical applications and propose suitable application scenarios based on these modified phages.

Simultaneous Determination of 32 Pyrrolizidine Alkaloids in Two Traditional Chinese Medicine Preparations by UPLC-MS/MS

Pyrrolizidine alkaloids (PAs) constitute a class of phytotoxin which demonstrates strong hepatotoxicity. In China, many plants containing PAs are used as traditional medicines or medicinal preparations, which could harm human health and safety. Xiaoyao Tablet (XYT) is an antidepressant drug registered in the European Union (EU), Compound Danshen Dropping Pills (CDDP) is a commonly used drug for coronary heart disease, and phase III clinical study is ongoing in the United States. The purpose of this study is to provide data to support the use of Chinese medicine preparations internationally and to establish analytical methods for 32 PAs in XYT and CDDP. The extraction parameters that were optimized include solid-phase extraction (SPE) cartridge, extraction method, and extraction solvent. Then ultra-performance liquid chromatography coupled with triple-quadrupole linear ion-traptandem mass spectrometry (UPLC-MS/MS) was developed to effectively and efficiently quantify the 32 PAs of the XYT and CDDP. The analytical methods for XYT and CDDP were verified respectively. For XYT, the analytical method for 32 PAs was linear, and the correlation coefficient r was greater than 0.994; the recovery (REC%) at 10-2000 μg/kg was 73.3%-118.5%, and the relative standard deviation (RSD%) was 2.1%-15.4%. The CDDP REC% was 71.8%-112.0%, and the RSD% was 2.0%-17.1%. This study provides technical and data support for the registration of Chinese patented medicines in the EU, controls quality and ensures safety, and is committed to the internationalization and standardization of Chinese patented medicines.

Current approaches of nanomedicines in the market and various stage of clinical translation

Compared with traditional drug therapy, nanomedicines exhibit intriguing biological features to increase therapeutic efficiency, reduce toxicity and achieve targeting delivery. This review provides a snapshot of nanomedicines that have been currently launched or in the clinical trials, which manifests a diversified trend in carrier types, applied indications and mechanisms of action. From the perspective of indications, this article presents an overview of the applications of nanomedicines involving the prevention, diagnosis and treatment of various diseases, which include cancer, infections, blood disorders, cardiovascular diseases, immuno-associated diseases and nervous system diseases, etc. Moreover, the review provides some considerations and perspectives in the research and development of nanomedicines to facilitate their translations in clinic.

Nanodrugs Targeting T Cells in Tumor Therapy

In contrast to conventional anti-tumor agents, nano-carriers allow co-delivery of distinct drugs in a cell type-specific manner. So far, many nanodrug-based immunotherapeutic approaches aim to target and kill tumor cells directly or to address antigen presenting cells (APC) like dendritic cells (DC) in order to elicit tumor antigen-specific T cell responses. Regulatory T cells (Treg) constitute a major obstacle in tumor therapy by inducing a pro-tolerogenic state in APC and inhibiting T cell activation and T effector cell activity. This review aims to summarize nanodrug-based strategies that aim to address and reprogram Treg to overcome their immunomodulatory activity and to revert the exhaustive state of T effector cells. Further, we will also discuss nano-carrier-based approaches to introduce tumor antigen-specific chimeric antigen receptors (CAR) into T cells for CAR-T cell therapy which constitutes a complementary approach to DC-focused vaccination.

Recent developments in capillary and microchip electroseparations of peptides (2019-mid 2021)

The review provides a comprehensive overview of developments and applications of high performance capillary and microchip electroseparation methods (zone electrophoresis, isotachophoresis, isoelectric focusing, affinity electrophoresis, electrokinetic chromatography, and electrochromatography) for analysis, microscale isolation, and physicochemical characterization of peptides from 2019 up to approximately the middle of 2021. Advances in the investigation of electromigration properties of peptides and in the methodology of their analysis, such as sample preparation, sorption suppression, EOF control, and detection, are presented. New developments in the individual CE and CEC methods are demonstrated and several types of their applications are shown. They include qualitative and quantitative analysis, determination in complex biomatrices, monitoring of chemical and enzymatic reactions and physicochemical changes, amino acid, sequence, and chiral analyses, and peptide mapping of proteins. In addition, micropreparative separations and determination of significant physicochemical parameters of peptides by CE and CEC methods are described.

Ultra-high-performance liquid chromatography coupled with quadrupole time of flight mass spectrometry method for quantifying polymer poloxamer 124 and its application to pharmacokinetic study

Poloxamer is a commonly used pharmaceutical excipient. It is a high molecular polymer formed using polypropylene oxide and polyethylene oxide units. Specifically, poloxamer 124 is one of the smaller molecular weight in the poloxamer series; however, its pharmacokinetic behaviors in vivo are still unclear. In this study, a method for quantifying poloxamer 124 in rat plasma through ultra-high-performance liquid chromatography coupled with quadrupole time of flight mass spectrometry was developed. The intravenous dosage of PL124 was 10 mg/kg. Plasma was collected at different times. The calibration curve was linear in the range of 0.1-5 μg/mL for the poloxamer 124 (r ≥ 0.9956) with the lower limit of quantitation of 0.1 μg/ml. The relative standard deviation of the intraday and interday precisions was below 8.0%, and the relative error of the accuracy was within ±12.0%. The extraction recovery, matrix effect, and stability were satisfactory in rat plasma. The validated method was successfully applied to a pharmacokinetic study of poloxamer 124 in rats. Results indicated that poloxamer 124 could be rapidly absorbed and eliminated through caudal vein injection. This study is helpful for the further study of poloxamer 124.

Mechanistic Understanding From Molecular Dynamics Simulation in Pharmaceutical Research 1: Drug Delivery

In this review, we outline the growing role that molecular dynamics simulation is able to play as a design tool in drug delivery. We cover both the pharmaceutical and computational backgrounds, in a pedagogical fashion, as this review is designed to be equally accessible to pharmaceutical researchers interested in what this new computational tool is capable of and experts in molecular modeling who wish to pursue pharmaceutical applications as a context for their research. The field has become too broad for us to concisely describe all work that has been carried out; many comprehensive reviews on subtopics of this area are cited. We discuss the insight molecular dynamics modeling has provided in dissolution and solubility, however, the majority of the discussion is focused on nanomedicine: the development of nanoscale drug delivery vehicles. Here we focus on three areas where molecular dynamics modeling has had a particularly strong impact: (1) behavior in the bloodstream and protective polymer corona, (2) Drug loading and controlled release, and (3) Nanoparticle interaction with both model and biological membranes. We conclude with some thoughts on the role that molecular dynamics simulation can grow to play in the development of new drug delivery systems.