The University of Southampton
University of Southampton Institutional Repository

Benchtop NMR analysis of piperazine-based drugs hyperpolarised by SABRE

Benchtop NMR analysis of piperazine-based drugs hyperpolarised by SABRE
Benchtop NMR analysis of piperazine-based drugs hyperpolarised by SABRE
Piperazine‐based drugs, such as N‐benzylpiperazine (BZP), became attractive in the 2000s due to possessing effects similar to amphetamines. Herein, BZP, in addition to its pyridyl analogues, 2‐, 3‐, and 4‐pyridylmethylpiperazine (2‐PMP, 3‐PMP, and 4‐PMP respectively) was subjected to the hyperpolarisation technique Signal Amplification By Reversible Exchange (SABRE) in order to demonstrate the use of this technique to detect these piperazine‐based drugs. Although BZP was not hyperpolarised via SABRE, 2‐PMP, 3‐PMP, and 4‐PMP were, with the ortho‐ and meta‐pyridyl protons of 4‐PMP showing the largest enhancement of 313‐fold and 267‐fold, respectively, in a 1.4‐T detection field, following polarisation transfer at Earth's magnetic field. In addition to the freebase, 4‐PMP.3HCl was also appraised by SABRE and was found not to polarise, however, the addition of increasing equivalents of triethylamine (TEA) produced the freebase, with a maximum enhancement observed upon the addition of 3 equivalents of TEA. Further addition of TEA led to a reduction in the observed enhancement. SABRE was also employed to polarise 4‐PMP.3HCl (~20% w/w) in a simulated tablet to demonstrate the forensic application of the technique (138‐fold enhancement for the ortho‐pyridyl protons). The amount of 4‐PMP.3HCl present in the simulated tablet was quantified via NMR using D2O as a solvent and compared well to complimentary gas chromatography–mass spectrometry data. Exchanging D2O for CD3OD as the solvent utilised for analysis resulted in a significantly lower amount of 4‐PMP.3HCl being determined, thus highlighting safeguarding issues linked to drug abuse in relation to determining the amount of active pharmaceutical ingredient present.
4-PMP, H, N-benzylpiperazine, NMR, SABRE, benchtop NMR, parahydrogen
0749-1581
1151-1159
Tennant, Thomas
feef7355-e908-4bae-8269-1fa91642ab6f
Hulme, Matthew
ea456e97-7ef5-4095-ae91-73d59ced600f
Robertson, Thomas
957b392c-1212-4721-bd6d-d1e00ed50a09
Sutcliffe, Oliver
2a341922-e966-483c-ad4e-44f4b8b661e5
Mewis, Ryan
c7ccb983-a35f-4d5f-8382-ecaca3cb6548
Tennant, Thomas
feef7355-e908-4bae-8269-1fa91642ab6f
Hulme, Matthew
ea456e97-7ef5-4095-ae91-73d59ced600f
Robertson, Thomas
957b392c-1212-4721-bd6d-d1e00ed50a09
Sutcliffe, Oliver
2a341922-e966-483c-ad4e-44f4b8b661e5
Mewis, Ryan
c7ccb983-a35f-4d5f-8382-ecaca3cb6548

Tennant, Thomas, Hulme, Matthew, Robertson, Thomas, Sutcliffe, Oliver and Mewis, Ryan (2020) Benchtop NMR analysis of piperazine-based drugs hyperpolarised by SABRE. Magnetic Resonance in Chemistry, 58 (12), 1151-1159. (doi:10.1002/mrc.4999).

Record type: Article

Abstract

Piperazine‐based drugs, such as N‐benzylpiperazine (BZP), became attractive in the 2000s due to possessing effects similar to amphetamines. Herein, BZP, in addition to its pyridyl analogues, 2‐, 3‐, and 4‐pyridylmethylpiperazine (2‐PMP, 3‐PMP, and 4‐PMP respectively) was subjected to the hyperpolarisation technique Signal Amplification By Reversible Exchange (SABRE) in order to demonstrate the use of this technique to detect these piperazine‐based drugs. Although BZP was not hyperpolarised via SABRE, 2‐PMP, 3‐PMP, and 4‐PMP were, with the ortho‐ and meta‐pyridyl protons of 4‐PMP showing the largest enhancement of 313‐fold and 267‐fold, respectively, in a 1.4‐T detection field, following polarisation transfer at Earth's magnetic field. In addition to the freebase, 4‐PMP.3HCl was also appraised by SABRE and was found not to polarise, however, the addition of increasing equivalents of triethylamine (TEA) produced the freebase, with a maximum enhancement observed upon the addition of 3 equivalents of TEA. Further addition of TEA led to a reduction in the observed enhancement. SABRE was also employed to polarise 4‐PMP.3HCl (~20% w/w) in a simulated tablet to demonstrate the forensic application of the technique (138‐fold enhancement for the ortho‐pyridyl protons). The amount of 4‐PMP.3HCl present in the simulated tablet was quantified via NMR using D2O as a solvent and compared well to complimentary gas chromatography–mass spectrometry data. Exchanging D2O for CD3OD as the solvent utilised for analysis resulted in a significantly lower amount of 4‐PMP.3HCl being determined, thus highlighting safeguarding issues linked to drug abuse in relation to determining the amount of active pharmaceutical ingredient present.

This record has no associated files available for download.

More information

Accepted/In Press date: 14 January 2020
e-pub ahead of print date: 16 January 2020
Published date: 1 December 2020
Additional Information: Funding Information: REM is grateful to Manchester Metropolitan University for a Vice Chancellor studentship for TBRR. Oxford Instruments are thanked for their technical support. Publisher Copyright: © 2020 John Wiley & Sons, Ltd.
Keywords: 4-PMP, H, N-benzylpiperazine, NMR, SABRE, benchtop NMR, parahydrogen

Identifiers

Local EPrints ID: 444154
URI: http://eprints.soton.ac.uk/id/eprint/444154
ISSN: 0749-1581
PURE UUID: 74f99ac9-4cf0-41a5-bbf8-a7cc951877b4
ORCID for Thomas Robertson: ORCID iD orcid.org/0000-0001-9394-6185

Catalogue record

Date deposited: 29 Sep 2020 17:39
Last modified: 06 Jun 2024 02:09

Export record

Altmetrics

Contributors

Author: Thomas Tennant
Author: Matthew Hulme
Author: Oliver Sutcliffe
Author: Ryan Mewis

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×