Development and validation of an improved liquid chromatography–mass spectrometry method for the determination of pemetrexed in human plasma

Eco-Friendly Stability-Indicating HPLC Method for Related Compounds in Pemetrexed Ditromethamine (Antineoplastic Agent) for Injection

BACKGROUND

An eco-friendly analytical technique was developed with the intention of preserving the environment by using green chemistry principles. Pemetrexed is a folate analogue indicated for the treatment of advanced lung cancer.

OBJECTIVE

Development of a green stability-indicating HPLC method for the quantification of pemetrexed ditromethamine (PDT) impurities in Active Pharmaceutical Ingredient (API) and parenteral dosage form.

METHODS

Chromatographic separation was achieved using a Zorbax SB C18 column (150 mm × 4.6 mm i.d., 3.5 µ particle size) with perchlorate buffer (pH 3.0 ± 0.1, 50 mM) as mobile phase A and acetonitrile-perchlorate (90 + 10, v/v) buffer as mobile phase B at a flow rate of 0.8 mL/min with a column temperature of 40°C ± 0.5°C. All analytes were well resolved by gradient elution with a total run time of 75 min. The UV detection wavelength was 230 nm.

RESULTS

The RP-HPLC method is capable of resolving all the degradation and process impurities for PDT API and parenteral dosage form. The related compounds method was validated in accordance with International conference on harmonization (ICH) Q2(R1) and United states of Pharmacopoeia (USP) <1225> guidelines, and found to be accurate, specific, precise, linear, robust and stability-indicating. The precision and intermediate results were <5% CV for all the impurities. The accuracy for all the impurities was found to be between 90 and 110%. The linearity of regression co-efficient values for all the impurities were found to be more than 0.999.

CONCLUSION

The proposed related compounds method is found suitable for the determination of process and degradation impurities of commercial formulations, stability samples in QC analysis for PDT API, and drug product.

HIGHLIGHTS

The developed liquid chromatographic method greenness and eco-friendliness were assessed using the green analytical procedure index (GAPI) and the analytical greenness (AGREE) tool, and found to be green. A PDT detoxification procedure was also developed to reduce environmental pollution.

A nanoscale electrochemical guanine DNA-biosensor based on a flower-like nanocomposite of Tb-doped ZnO for the sensitive determination of pemetrexed

Pemetrexed is an antineoplastic drug used in chemotherapeutic treatments, especially in malignant mesothelioma and non-small cell lung carcinoma, but can also cause a variety of complications, like stomach pain, nausea, burning, vomiting, numbness, and tingling, emphasizing the need for an approach to quantify the drug in biological matrices. Herein, a DNA-based biosensor was introduced for pemetrexed determination. A hydrothermal approach was used for synthesizing flower-like nanoparticles (NPs) of zinc oxide (ZnO) doped with Tb (FL-NP Tb3+/ZnO). Moreover, energy dispersive X-ray (EDX), field-emission scanning electron microscopy (FESEM), zeta potential, Brunauer-Emmett-Teller (BET), and X-ray diffraction (XRD) analyses were used for characterizing the as-prepared nanocomposite. According to the impedance analysis, FL-NP Tb3+/ZnO was accompanied by very good electrochemical functions for a simple transfer of electrons. In the case of the immobilization of double-stranded deoxyribonucleic acid (ds-DNA) on the FL-NP Tb3+/ZnO and polypyrrole (PP)-modified pencil graphite electrode (ds-DNA/PP/FL-NP Tb3+/ZnO/PGE), a considerable enhancement was found in the electrochemical oxidation of guanine in ds-DNA residue bases. Since there was an interaction between ds-DNA and pemetrexed, the voltammetric current of guanine over the ds-DNA/PP/FL-NP Tb3+/ZnO/PGE declined in the presence of pemetrexed in the electrolytic solution. Moreover, under optimum conditions (25 mg L-1 of ds-DNA and 10 min incubation time, in acetate buffer at 25 °C), a linear decrease in the guanine signal was observed on the ds-DNA/PP/FL-NP Tb3+/ZnO/PGE as the pemetrexed concentration increased in the range from 0.001 μM to 175.0 μM with a limit of detection of 0.17 nM. Finally, the new DNA-based biosensor was successfully used for determining pemetrexed in real samples, indicating its application potential.

A Drug Stability Study Using Surface-Enhanced Raman Scattering on Silver Nanoparticles

Pharmaceutical product quality is of vital importance for patient safety. Impurities and potential degradation products can cause changes in chemistry, pharmacological and toxicological properties by having a significant impact on product quality and safety. Stress-testing (forced degradation) studies of pharmaceutical preparations became necessary to assure degradation mechanisms and potential degradation products. Consequently, it is crucial to understand the nature of possible degradation products. Surface-enhanced Raman spectroscopy (SERS) is a powerful vibrational spectroscopic technique that can provide valuable information about changes in a molecular structure with its intrinsic finger-print property. In this study, a forced degradation study was conducted on pemetrexed (PMT), an antifolate chemotherapy drug, in order to identify its likely chemical degradation products. The degradation mechanism of PMT was investigated under various experimental conditions; basic (0.1 M NaOH), acidic (0.1 M HCl), and oxidative (3% H2O2v/v). We used silver nanoparticles (AgNPs) of average size 60 nm as SERS substrates. The study shows that SERS can be a fast and reliable technique to study the stability and possible degradation mechanisms of drugs under several different conditions.

A stability-indicating LC-MS/MS method optimization for Pemetrexed through design of experiments: Identification and characterization of major oxidative degradation product

A stability-indicating high-performance liquid chromatography method for Pemetrexed bulk was developed and validated as per the ICH guidelines by employing design of experiments methodology equipped with Box-Behnken design. The separation of Pemetrexed and its oxidative degradation product was achieved in isocratic elution mode with Zorbax C₁₈ column (150 mm x 4.6 mm x5 μm) using 10 mM ammonium acetate (pH 4.5 adjusted with acetic acid) and acetonitrile in the ratio of 50:50, v/v with a flow rate of 1.0 mL/min at detection wavelength of 223 nm. Tandem mass spectrometry method was adopted to identify and characterize the major oxidative degradation product. The results obtained indicate that the method is specific, linear, precise and accurate for the determination of Pemetrexed and characterization of degradation product.

Intestinal transport mechanism and in vivo anticancer efficacy of a solid oral formulation incorporating an ion-pairing complex of pemetrexed with deoxycholic acid derivative

Objective

The rational combination of immunotherapy with standard chemotherapy shows synergistic clinical activities in cancer treatment. In the present study, an oral powder formulation of pemetrexed (PMX) was developed to enhance intestinal membrane permeability and investigate its application in metronomic chemotherapy in combination with immunotherapy.

Methods

PMX was ionically complexed with a bile acid derivative (N^α-deoxycholyl-l-lysyl-methylester; DCK) as a permeation enhancer and mixed with dispersing agents, such as poloxamer 188 (P188) and Labrasol, to form an amorphous oral powder formulation of PMX/DCK (PMX/DCK-OP).

Results

The apparent permeability (P_app) of PMX/DCK-OP across a Caco-2 cell monolayer was 2.46- and 8.26-fold greater than that of PMX/DCK and free PMX, respectively, which may have been due to the specific interaction of DCK with bile acid transporters, as well as the alteration of membrane fluidity due to Labrasol and P188. Furthermore, inhibition of bile acid transporters by actinomycin D in Caco-2 cell monolayers decreased the P_app of PMX/DCK-OP by 75.4%, suggesting a predominant role of bile acid transporters in the intestinal absorption of PMX/DCK-OP. In addition, caveola/lipid raft-dependent endocytosis, macropinocytosis, passive diffusion, and paracellular transport mechanisms significantly influenced the permeation of PMX/DCK-OP through the intestinal membrane. Therefore, the oral bioavailability of PMX/DCK-OP in rats was 19.8%±6.93%, which was 294% higher than that of oral PMX. Moreover, an in vivo anticancer efficacy study in B16F10 cell-bearing mice treated with a combination of oral PMX/DCK-OP and intraperitoneal anti-PD1 exhibited significant suppression of tumor growth, and the tumor volume was maximally inhibited by 2.03- and 3.16-fold compared to the oral PMX/DCK-OP and control groups, respectively.

Conclusion

These findings indicated the therapeutic potential of a combination of low-dose oral chemotherapy and immunotherapy for synergistic anticancer efficacy.

Simple and Rapid Quantification of the Multi-Enzyme Targeting Antifolate Pemetrexed in Human Plasma

BACKGROUND

Pemetrexed is an antifolate cytostatic drug that targets multiple enzymes involved in folate biosynthesis and is indicated for treatment of non-small-cell lung cancer and malignant pleural mesothelioma. As evidence for an exposure-response/toxicity relationship is accumulating, dose individualization using therapeutic drug monitoring may be a feasible strategy to optimize treatment. The purpose of this study was to develop a simple, sensitive, high-performance liquid chromatography method with UV detection for quantification of pemetrexed levels in human plasma.

METHOD

The method involves a simple protein precipitation, followed by ultra-performance liquid chromatography with ultraviolet detection at a wavelength of 254 nm. Pemetrexed was separated using a mobile phase with a linear gradient and a run time of only 7 minutes.

RESULTS

The assay has been validated over the concentration range 0.25-500 mg/L of pemetrexed. Accuracy for this assay ranged from -4.50% to 1.78%, and the within- and between-run coefficients of variation were <3.57%. Pemetrexed in plasma was proven to be stable for 8 months at -40°C.

CONCLUSIONS

The bioanalytical method we developed proved to be simple, accurate, precise, and fast. This analytical method is successfully in use for therapeutic drug monitoring and will be used for pharmacokinetic studies.

Preparation, Characterization, and In Vivo Evaluation of an Oral Multiple Nanoemulsive System for Co-Delivery of Pemetrexed and Quercetin

Co-administration of conventional and natural chemotherapeutics offers synergistic anticancer efficacy while minimizing adverse effects. In this study, an oral co-delivery system for pemetrexed (PMX) and quercetin (QCN) was designed based on water-in-oil-in-water nanoemulsion (NE), which is highly absorbable because it enhances the intestinal membrane permeability of PMX and aqueous solubility of QCN. To create this system, an ion-pairing complex of PMX with N^α-deoxycholyl-l-lysyl-methylester (DCK) was formed and further incorporated with QCN into the NE, yielding PMX/DCK-QCN-NE. The results revealed synergistic inhibitory effects on human lung carcinoma (A549) cell proliferation and migration after combined treatment with PMX/DCK and QCN. The intestinal membrane permeability and cellular uptake of PMX/DCK and QCN from the NE were significantly improved via facilitated transport of PMX by the interaction of DCK with bile acid transporters, as well as NE formulation-mediated alterations in the membrane structure and fluidity, which resulted in 4.51- and 23.9-fold greater oral bioavailability of PMX and QCN, respectively, than each free drug. Tumor growth in A549 cell-bearing mice was also maximally suppressed by 62.7% after daily oral administration of PMX/DCK-QCN-NE compared with controls. Thus, PMX/DCK-QCN-NE is a promising oral nanocarrier of PMX and QCN for synergistic anticancer efficacy and long-term chemotherapy.

Antineoplastic drugs and their analysis: a state of the art review

We provide an overview of the analytical methods available for the quantification of antineoplastic drugs in pharmaceutical formulations, biological and environmental samples.

Electrochemical preparation of sodium dodecylsulfate doped over-oxidized polypyrrole/multi-walled carbon nanotube composite on glassy carbon electrode and its application on sensitive and selective determination of anticancer drug: pemetrexed

Electrochemical oxidation of pemetrexed (PMX) was studied on bare, carboxylic acid functionalized multi-walled carbon nanotubes and over-oxidized polypyrrole modified (oo-PPy/MWCNTs-COOH/GCE) glassy carbon electrodes by cyclic and adsorptive stripping differential pulse voltammetric techniques. The oo-PPy/MWCNTs-COOH/GCE is very sensitive to the oxidation of PMX. The results proved that the over-oxidation of the PPy film gave a negative charge density on porous layer that improved the adsorption for PMX. The effects of pH, concentrations of MWCNTs and monomer, the number of cycles for the electropolymerization and the scan rate for sensor preparation were optimized. The MWCNTs-COOH and oo-PPy based sensor showed an excellent recognition capacity toward PMX. The linear responses have been obtained in the range from 8.00 × 10(-7)M to 1.00 × 10(-4)M with 2.04 × 10(-7)M detection limit for the bare GCE and from 1.00 × 10(-8)M to 1.00 × 10(-7)M with 3.28 × 10(-9)M detection limit for the modified GCE. The oxidation of PMX was controlled by the adsorption process on both types of electrode surfaces. The proposed methods were compared with the literature on UV spectrophotometric assay, which was carried out at an absorption maximum of 225 nm. The proposed method and the designed sensors have been successfully applied for the determination of PMX in pharmaceuticals.

A phase 1 study of TRC102, an inhibitor of base excision repair, and pemetrexed in patients with advanced solid tumors

INTRODUCTION

TRC102 potentiates the activity of cancer therapies that induce base excision repair (BER) including antimetabolite and alkylating agents. TRC102 rapidly and covalently binds to apurinic/apyrimidinic (AP) sites generated during BER, and TRC102-bound DNA causes topoisomerase II-dependent irreversible strand breaks and apoptosis. This study assessed the safety, maximum-tolerated dose (MTD), pharmacokinetics and pharmacodynamics of TRC102 alone and in combination with pemetrexed.

PURPOSE

Patients with advanced solid tumors received oral TRC102 daily for 4 days. Two weeks later, patients began standard-dose pemetrexed on day 1 in combination with oral TRC102 on days 1 to 4. The pemetrexed-TRC102 combination was repeated every 3 weeks until disease progression.

METHODS

Twenty-eight patients were treated with TRC102 at 15, 30, 60 or 100 mg/m(2)/d. The MTD was exceeded at 100 mg/m(2)/d due to grade 3 anemia in 50 % of patients. TRC102 exposure increased in proportion to dose with a mean t1/2 of 28 h. A pharmacodynamic assay confirmed that TRC102 binds to pemetrexed-induced AP sites at all doses studied. Stable disease or better was achieved in 15 of 25 patients evaluable for response (60 %), including one patient with recurrent metastatic oropharyngeal carcinoma that expressed high levels of thymidylate synthase, who achieved a partial response and was progression free for 14 months.

CONCLUSIONS

When administered with pemetrexed, the maximum tolerated dose of oral TRC102 is 60 mg/m(2)/d for 4 days. Randomized controlled studies are planned to evaluate the clinical benefit of adding TRC102 to pemetrexed and other agents that induce BER.

Analysis of anticancer drugs: a review

In the last decades, the number of patients receiving chemotherapy has considerably increased. Given the toxicity of cytotoxic agents to humans (not only for patients but also for healthcare professionals), the development of reliable analytical methods to analyse these compounds became necessary. From the discovery of new substances to patient administration, all pharmaceutical fields are concerned with the analysis of cytotoxic drugs. In this review, the use of methods to analyse cytotoxic agents in various matrices, such as pharmaceutical formulations and biological and environmental samples, is discussed. Thus, an overview of reported analytical methods for the determination of the most commonly used anticancer drugs is given.

A novel fluorescence-based assay for the rapid detection and quantification of cellular deoxyribonucleoside triphosphates

Current methods for measuring deoxyribonucleoside triphosphates (dNTPs) employ reagent and labor-intensive assays utilizing radioisotopes in DNA polymerase-based assays and/or chromatography-based approaches. We have developed a rapid and sensitive 96-well fluorescence-based assay to quantify cellular dNTPs utilizing a standard real-time PCR thermocycler. This assay relies on the principle that incorporation of a limiting dNTP is required for primer-extension and Taq polymerase-mediated 5–3′ exonuclease hydrolysis of a dual-quenched fluorophore-labeled probe resulting in fluorescence. The concentration of limiting dNTP is directly proportional to the fluorescence generated. The assay demonstrated excellent linearity (R² > 0.99) and can be modified to detect between ∼0.5 and 100 pmol of dNTP. The limits of detection (LOD) and quantification (LOQ) for all dNTPs were defined as <0.77 and <1.3 pmol, respectively. The intra-assay and inter-assay variation coefficients were determined to be <4.6% and <10%, respectively with an accuracy of 100 ± 15% for all dNTPs. The assay quantified intracellular dNTPs with similar results obtained from a validated LC–MS/MS approach and successfully measured quantitative differences in dNTP pools in human cancer cells treated with inhibitors of thymidylate metabolism. This assay has important application in research that investigates the influence of pathological conditions or pharmacological agents on dNTP biosynthesis and regulation.

A new ultrafast and high-throughput mass spectrometric approach for the therapeutic drug monitoring of the multi-targeted anti-folate pemetrexed in plasma from lung cancer patients

An analytical assay has been developed and validated for ultrafast and high-throughput mass spectrometric determination of pemetrexed concentrations in plasma using matrix assisted laser desorption/ionization–triple quadrupole–tandem mass spectrometry. Patient plasma samples spiked with the internal standard methotrexate were measured by multiple reaction monitoring. The detection limit was 0.4 fmol/μL, lower limit of quantification was 0.9 fmol/μL, and upper limit of quantification was 60 fmol/μL, respectively. Overall observed pemetrexed concentrations in patient samples ranged between 8.7 (1.4) and 142.7 (20.3) pmol/μL (SD). The newly developed mass spectrometric assay is applicable for (routine) therapeutic drug monitoring of pemetrexed concentrations in plasma from non-small cell lung cancer patients.