Rapid and simple flow injection analysis tandem mass spectrometric method for the quantification of melphalan in a lipid‐based drug delivery system

Abstract

Rationale: The use of the anticancer drug melphalan is limited due to its poor water solubility.To address this limitation, it is incorporated within a novel delivery system using β-cyclodextringemini surfactants (18:1βCDg).Methods: Herein, two fast and simple flow injection analysis/tandem mass spectrometric (FIA-MS/MS) methods are developed for the quantification of melphalan (Mel) within the drug delivery system so that the solubilization efficiency of the system can be assessed. FIA-MS/MS methods are developed using a triple quadrupole linear ion trap mass spectrometer, equipped with electrospray ionization (ESI) in the positive ion mode. A deuterated form of melphalan (melphalan-d8) was used as an internal standard (IS). The methods were validated according to the FDA guidance.Results: A linearity in the range of 2-100 ng/mL and accuracy and precision below 15% were observed for all standard points and quality control samples. The intra-and inter-day variations and freeze-thaw stability were within the acceptable range according to the criteria set by regulatory guidelines. On the other hand, other stability measures, such as room temperature stability and long-term stability, did not meet the required guidelines in some cases, indicating the need for quick sample analysis upon preparation. Such a fact could have been overlooked if full method validation had not been performed. Conclusions:The developed methods were applied to determine the encapsulation/ solubilization of the [18:1βCDg/Mel] delivery system. 18:1βCDg enhances the aqueous solubility of melphalan without the need for co-solvent. The highest melphalan solubility was observed at a melphalan18:1βCDg/Mel complex molar ratio of 2:1. This study demonstrated that a fast analysis for the purpose of quantifying a chemically unstable drug, such as melphalan, is feasible and important for the development of commercial dosage forms.

Inclusion Complexes of Melphalan with Gemini-Conjugated β-Cyclodextrin: Physicochemical Properties and Chemotherapeutic Efficacy in In-Vitro Tumor Models

“…In the present study, the “cooperative interaction” only occurred when Mel was added to the 18:1βCDg. The foregoing solubility results inferred from the 2D NMR results agree with the CIS data herein (Table 1) and with solubility evaluation results reported previously using mass spectrometry [41]. The 1 H NMR CIS data in Table 1 provide evidence of destabilization of the carrier–drug inclusion complex due to hydrophobic effects and conformational motility of the 18:1βCDg at higher carrier loading, as indicated by the downfield shifts of the βCD extracavity (or framework) nuclei (i.e., H 1 , H 6 , and H 4 ).…”

“…The phase-solubility relationship describes only the solubilizing effect of the CD on the drug molecule but not the actual formation of inclusion complexes. Based on the phase-solubility diagram of Higuchi and Connors, the solubility evaluation results reported previously using flow-injection mass spectrometry of 18:1βCDg-Mel [41] and the NMR results discussed herein, we propose that the relationship between the solubility of Mel and the concentration of the host (18:1βCDg) follows either A N or A-B S -type model. A N -type model indicates the formation of a host–drug soluble complex with negatively deviating isotherms, whereas the A-B S -type indicates the formation of a complex with limited solubility [43].…”

“…The 1 H NMR CIS data in Table 1 provide evidence of destabilization of the carrier–drug inclusion complex due to hydrophobic effects and conformational motility of the 18:1βCDg at higher carrier loading, as indicated by the downfield shifts of the βCD extracavity (or framework) nuclei (i.e., H 1 , H 6 , and H 4 ). The efficiency of 18:1βCDg to increase the aqueous solubility of Mel was evaluated using mass spectrometry, where the highest aqueous solubility was determined at the 2:1 host–guest mole ratio [41]. Increasing the 18:1βCDg-Mel mole ratios to 3:1 and 5:1 caused significant reduction in Mel solubility, consistent with the attenuated βCD-Mel signals at the expense of the βCD-gemini surfactant signals for these systems (cf.…”

The development of simple flow injection analysis tandem mass spectrometric methods for the cutaneous determination of peptide-modified cationic gemini surfactants used as gene delivery vectors

“…loop injection) has emerged as an effective approach that offers a rapid sample possessing rate, low cost, and method simplicity [31]. It has been successfully applied in the quantitation of several analytes, including pharmaceuticals, environmental contaminants, and endogenous compounds [32,33]. Therefore, FIA-MS/MS methods were developed removing the need for chromatographic separation while relying on the MS separation capabilities.…”