Browsing by Author "Krol, Ed"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
Item Mass Spectrometric Detection and Characterization of Metabolites of Gemini Surfactants Used as Gene Delivery Vectors(2020) Jin, Wei; Purves, Randy; Krol, Ed; Badea, ildiko; El-Aneed, AnasGemini surfactants are a class of lipid molecules that have been successfully used in vitro and in vivo as non-viral gene delivery vectors. However, the biological fate of gemini surfactants has not been well investigated. In particular, the metabolism of gemini surfactants after they enter cells as gene delivery vehicles is unknown. In this work, we used a high-resolution quadrupole-Orbitrap mass spectrometry (Q-Exactive®) instrument to detect the metabolites of three model gemini surfactants, namely a) unsubstituted (16-3-16), b) with pyridinium head groups (16(Py)-S-2-S-16(Py)), and c) substituted with a glycyl-lysine di-peptide (16-7N(GK)-16). The metabolites were characterized, and structures proposed, based on accurate masses and characteristic product ions. The metabolism of the three gemini surfactants was very different as 16-3-16 was not metabolized in PAM212 cells, whereas 16(Py)-S-2-S-16(Py) was metabolized primarily via phase I reactions, including oxidation and de-alkylation, producing metabolites that could be linked to its observed high toxicity. The third gemini surfactant 16-7N(GK)-16 was metabolized mainly via phase II reactions, including methylation, acetylation, glucose conjugation, palmityl conjugation, and stearyl conjugation. The metabolism of gemini surfactants provides insight for future directions in the design and development of more effective gemini surfactants with lower toxicity. The reported approach can also be applied to study the metabolism of other structurally related gemini surfactants.Item Tandem mass spectrometric analysis of novel caffeine scaffold-based bifunctional compounds for Parkinson's disease(2019) Nwabufo, Chukwunonso; El-Aneed, Anas; Krol, EdRationale: Novel bifunctional compounds composed of a caffeine scaffold attached to nicotine (C8-6-N), 1-aminoindan (C8-6-I), or caffeine (C8-6-C8) were designed as therapeutics or diagnostics for Parkinson's disease (PD). In order to probe their pharmacological and toxicological profile, an appropriate analytical method is required. The goal of this study is to establish a tandem mass spectrometric fingerprint for the development of quantitative and qualitative methods that will aid future assessment of the in vitro and in vivo absorption, distribution, metabolism, excretion (ADME) and pharmacokinetic properties of these lead bifunctional compounds for PD. Methods: Accurate mass measurement was performed using a hybrid quadrupole orthogonal time-of-flight mass spectrometer while multistage MS/MS and MS3 analyses were conducted using a triple quadrupole linear ion trap mass spectrometer. Both instruments are equipped with an electrospray ionization (ESI) source and were operated in the positive ion mode. The source and compound parameters were optimized for all three tested bifunctional compounds. Results: The MS/MS analysis indicates that the fragmentation of C8-6-N and C8-6-I is driven by the dissociation of the nicotine and 1-aminoindan moieties, respectively, but not caffeine. A significant observation in the MS/MS fragmentation of C8-6-C8 suggests that a previously reported loss of acetaldehyde during caffeine dissociation is instead a loss of CO2. Conclusions: The collision-induced tandem mass spectrometry (CID-MS/MS) analysis of these novel bifunctional compounds revealed compound-specific diagnostic product ions and neutral losses for all three tested bifunctional compounds. The established MS/MS fingerprint will be applied to the future development of qualitative and quantitative methods.