Quantitative analysis of polypropylene glycol polymers by liquid chromatography tandem mass spectrometry based on collision induced dissociation technique

A strategy of accuracy quantification by extending the concentration monitoring coverage based on online double collision energy of ultra-high performance liquid chromatography tandem mass spectrometry: The pharmacokinetics of Toddalia asiatica as a case study

To facilitate the safety, efficacy and rationality of clinical application of traditional Chinese medicines (TCMs), pharmacokinetic research played an indispensable role. The key challenge during pharmacokinetic investigation lied at the substantial fluctuation of compound concentrations in the plasma over the course of absorption. Taking the pharmacokinetics of six compounds after administration of Toddalia asiatica (TA) as an example, an efficient strategy was established by introducing the online double collision energy (ODCE) into the quantification process applying ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). During the analytical program, double collision energy (DCE) was optimized to establish the dual calibration curve (DCC) with large concentration monitoring coverage (CMC) for meeting the wide content range of certain target compounds. Method validation test was performed in terms of linearity, precision, sensitivity, matrix effect, recovery, etc. The results displayed that the CMC of todarolactone with high exposure in plasma was extended from 1.25-2,500 ng/mL to 1.25-125,000 ng/mL. Furthermore, a rapid UHPLC-MS/MS method integrated with ODCE was successfully applied to the determination of six compounds in rat plasma, revealing an extremely high plasma concentration of todarolactone (16,662 ng/mL). This strategy could expand the range of quantification while retaining extraordinary sensitivity. Consequently, it could be a fit-for-purpose strategy to quantify compounds over a wide concentration range for in vivo process monitoring.

Ultra-high-performance liquid chromatography with tandem mass spectrometry method for cellular toxicity and pharmacokinetic study of PEG1K polymers

Polyethylene glycol (PEG) is one of the most commonly used polymers in drug delivery systems. The investigation of the pharmacokinetic behavior of PEG is important for revealing the toxicity and efficiency of PEG-related Nano-drug delivery systems. A high through-put and selective ultra-high-performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) method coupled with collision-induced dissociation (CID) in source technique was developed and validated to determine PEG1K polymers in cellular samples in this study. The countless precursor ions of PEG1K are dissociated in the source to generate numerous product ions which have different numbers of subunits. The transition of [M+H]+ precursor ions → product ions at m/z 177.1 (four subunits)→89.1 (two subunits) was selected to determine PEG1K due to its high sensitivity. The UHPLC-MS/MS method coupled with CID in the source showed good linearity over the range of 0.1-10 μg/mL. Intra-day and inter-day accuracies and precisions of the assay were all within ± 12.39%. The assay was successfully applied to a cellular pharmacokinetic study of PEG1K in human breast cancer cells. The cytotoxicity of PEG1K polymers was also studied and the results indicated that the cytotoxicity of PEG1K was not significant in the range of 5-1200 μg/mL.

Unraveling the in vivo biological fate of mPEG2000-PDLLA2500-COOH diblock copolymers by LC-MS/MS based on CID in source technique

Methoxy poly (ethylene glycol)-poly(D, L-lactic acid) (mPEG-PDLLA) is a biocompatible and amphiphilic diblock copolymer composed of a hydrophilic poly(ethylene glycol) block and a hydrophobic poly(D, L-lactic acid) block, which can self-assemble into micelles in aqueous solution. It is one of the most widely used diblock copolymers for drug delivery, drug solubilization and drug encapsulation. Fully characterizing the in vivo fate of mPEG-PDLLA diblock copolymers is important to promote the further development of polymer-based nanocarrier drug delivery systems. However, to date, a bioanalysis assay for simultaneous quantification of mPEG-PDLLA and mPEG has not been reported. In this study, we developed such a novel LC-MS/MS assay based on CID in source technique and used it to study the multiple-dose pharmacokinetic, tissue distribution and excretion of mPEG2000-PDLLA2500-COOH and mPEG2000 in rat after intravenous administration. The results indicate that mPEG2000-PDLLA2500-COOH and mPEG2000 are mainly distributed to the liver, lung, spleen and kidney after intravenous administration. mPEG2000-PDLLA2500-COOH is mostly excreted via the renal route in the form of mPEG2000. Overall, the results of this study provide a comprehensive and clear picture of the in vivo fate of mPEG2000-PDLLA2500-COOH which will be useful in evaluating the efficiency and safety of polymer-based nanocarrier drug delivery systems.

Cooking food in microwavable plastic containers: in situ formation of a new chemical substance and increased migration of polypropylene polymers

Microwavable plastic food containers can be a source of toxic substances. Plastic materials such as polypropylene polymers are typically employed as safe materials in food packaging, but recent research demonstrates the migration of plastic substances or their by-products to food simulants, to foodstuff, and, more recently, to the human body through food consumption. However, a thorough evaluation of foodstuff in food contact materials under cooking conditions has not yet been undertaken. Here we show for the first time that plastic migrants present in food contact materials can react with natural food components resulting in a compound that combines a UV-photoinitiator (2-hydroxy-2-methyl-1-phenylpropan-1-one) with maltose from potato starch; this has been identified after cooking potatoes in microwavable plastic food containers. Additionally, polypropylene glycol substances have been found to transfer into food through microwave cooking. Identifying these substances formed in situ requires state-of-the-art high-resolution mass spectrometry instrumentation and metabolomics-based strategies.