A preliminary investigation to group disparate batches of licit and illicit diazepam tablets using differential scanning calorimetry

S. Bibi, David H. Bremner, Mavis Macdougall-Heasman, R. Reid, K. Simpson, A. Tough, S. Waddell, Isobel Stewart, K. H. Matthews

Research output: Contribution to journalArticle

6 Citations (Scopus)
44 Downloads (Pure)

Abstract

Increasing numbers of illicit and unlicensed medicines are in general circulation and regularly seized by the police and other regulatory authorities. Forensic identification of seized tablets tends to focus on visual appearance and chromatographic identification of the contained drug. This process is relatively time consuming and places a strain on forensic laboratories. It was therefore of interest to investigate the possible application of differential scanning calorimetry (DSC) as a fast and efficient tool to facilitate the identification of contained drug/s and associated tablet excipients. Sixteen different cases (Cases A to P) of diazepam tablets obtained from Police Scotland were characterised based on visual appearance (colour and manufacturers' logos), physical attributes (size, weight and hardness), drug type, drug quantity (HPLC) and thermal properties (DSC). Raw DSC data was further processed using principal component analysis (PCA) as an objective assessment of the thermograms obtained with a view to statistical grouping of different cases. Cases J/K, M/O and L/P could be paired on visual appearance and Cases B/C/E/G and J/K/L/P on tablet hardness (17–23 and 80–89 N respectively). HPLC indicated that 75% of the cases examined contained diazepam but less than half of these contained the recognised amount (10 mg); Cases B/E/L/P contained phenazepam and J/K contained etizolam. The thermal signatures of individual tablets provided by DSC produced qualitative information about both drugs and excipients, indicating lactose in Cases D/F/H/I/J/K/M/N/O and Emcompress™ in B/E/L/P. In particular, DSC coupled with PCA provided confident groupings of A/C/G, B/E/L/P and H/I/J/K, and specific pairings of B/E, L/P and F/N.
Original languageEnglish
Pages (from-to)8597-8604
Number of pages8
JournalAnalytical Methods
Volume7
Issue number20
Early online date20 Aug 2015
DOIs
Publication statusPublished - 8 Oct 2015

Fingerprint

Diazepam
Tablets
Differential scanning calorimetry
Pharmaceutical Preparations
Excipients
Law enforcement
Principal component analysis
Hardness
Lactose
Medicine
Thermodynamic properties
Color

Cite this

Bibi, S. ; Bremner, David H. ; Macdougall-Heasman, Mavis ; Reid, R. ; Simpson, K. ; Tough, A. ; Waddell, S. ; Stewart, Isobel ; Matthews, K. H. / A preliminary investigation to group disparate batches of licit and illicit diazepam tablets using differential scanning calorimetry. In: Analytical Methods. 2015 ; Vol. 7, No. 20. pp. 8597-8604.
@article{a52eaa815ea84962842f2d4aa3688084,
title = "A preliminary investigation to group disparate batches of licit and illicit diazepam tablets using differential scanning calorimetry",
abstract = "Increasing numbers of illicit and unlicensed medicines are in general circulation and regularly seized by the police and other regulatory authorities. Forensic identification of seized tablets tends to focus on visual appearance and chromatographic identification of the contained drug. This process is relatively time consuming and places a strain on forensic laboratories. It was therefore of interest to investigate the possible application of differential scanning calorimetry (DSC) as a fast and efficient tool to facilitate the identification of contained drug/s and associated tablet excipients. Sixteen different cases (Cases A to P) of diazepam tablets obtained from Police Scotland were characterised based on visual appearance (colour and manufacturers' logos), physical attributes (size, weight and hardness), drug type, drug quantity (HPLC) and thermal properties (DSC). Raw DSC data was further processed using principal component analysis (PCA) as an objective assessment of the thermograms obtained with a view to statistical grouping of different cases. Cases J/K, M/O and L/P could be paired on visual appearance and Cases B/C/E/G and J/K/L/P on tablet hardness (17–23 and 80–89 N respectively). HPLC indicated that 75{\%} of the cases examined contained diazepam but less than half of these contained the recognised amount (10 mg); Cases B/E/L/P contained phenazepam and J/K contained etizolam. The thermal signatures of individual tablets provided by DSC produced qualitative information about both drugs and excipients, indicating lactose in Cases D/F/H/I/J/K/M/N/O and Emcompress™ in B/E/L/P. In particular, DSC coupled with PCA provided confident groupings of A/C/G, B/E/L/P and H/I/J/K, and specific pairings of B/E, L/P and F/N.",
author = "S. Bibi and Bremner, {David H.} and Mavis Macdougall-Heasman and R. Reid and K. Simpson and A. Tough and S. Waddell and Isobel Stewart and Matthews, {K. H.}",
year = "2015",
month = "10",
day = "8",
doi = "10.1039/C5AY01711D",
language = "English",
volume = "7",
pages = "8597--8604",
journal = "Analytical Methods",
issn = "1759-9660",
publisher = "Royal Society of Chemistry",
number = "20",

}

A preliminary investigation to group disparate batches of licit and illicit diazepam tablets using differential scanning calorimetry. / Bibi, S.; Bremner, David H.; Macdougall-Heasman, Mavis; Reid, R.; Simpson, K.; Tough, A.; Waddell, S.; Stewart, Isobel; Matthews, K. H.

In: Analytical Methods, Vol. 7, No. 20, 08.10.2015, p. 8597-8604.

Research output: Contribution to journalArticle

TY - JOUR

T1 - A preliminary investigation to group disparate batches of licit and illicit diazepam tablets using differential scanning calorimetry

AU - Bibi, S.

AU - Bremner, David H.

AU - Macdougall-Heasman, Mavis

AU - Reid, R.

AU - Simpson, K.

AU - Tough, A.

AU - Waddell, S.

AU - Stewart, Isobel

AU - Matthews, K. H.

PY - 2015/10/8

Y1 - 2015/10/8

N2 - Increasing numbers of illicit and unlicensed medicines are in general circulation and regularly seized by the police and other regulatory authorities. Forensic identification of seized tablets tends to focus on visual appearance and chromatographic identification of the contained drug. This process is relatively time consuming and places a strain on forensic laboratories. It was therefore of interest to investigate the possible application of differential scanning calorimetry (DSC) as a fast and efficient tool to facilitate the identification of contained drug/s and associated tablet excipients. Sixteen different cases (Cases A to P) of diazepam tablets obtained from Police Scotland were characterised based on visual appearance (colour and manufacturers' logos), physical attributes (size, weight and hardness), drug type, drug quantity (HPLC) and thermal properties (DSC). Raw DSC data was further processed using principal component analysis (PCA) as an objective assessment of the thermograms obtained with a view to statistical grouping of different cases. Cases J/K, M/O and L/P could be paired on visual appearance and Cases B/C/E/G and J/K/L/P on tablet hardness (17–23 and 80–89 N respectively). HPLC indicated that 75% of the cases examined contained diazepam but less than half of these contained the recognised amount (10 mg); Cases B/E/L/P contained phenazepam and J/K contained etizolam. The thermal signatures of individual tablets provided by DSC produced qualitative information about both drugs and excipients, indicating lactose in Cases D/F/H/I/J/K/M/N/O and Emcompress™ in B/E/L/P. In particular, DSC coupled with PCA provided confident groupings of A/C/G, B/E/L/P and H/I/J/K, and specific pairings of B/E, L/P and F/N.

AB - Increasing numbers of illicit and unlicensed medicines are in general circulation and regularly seized by the police and other regulatory authorities. Forensic identification of seized tablets tends to focus on visual appearance and chromatographic identification of the contained drug. This process is relatively time consuming and places a strain on forensic laboratories. It was therefore of interest to investigate the possible application of differential scanning calorimetry (DSC) as a fast and efficient tool to facilitate the identification of contained drug/s and associated tablet excipients. Sixteen different cases (Cases A to P) of diazepam tablets obtained from Police Scotland were characterised based on visual appearance (colour and manufacturers' logos), physical attributes (size, weight and hardness), drug type, drug quantity (HPLC) and thermal properties (DSC). Raw DSC data was further processed using principal component analysis (PCA) as an objective assessment of the thermograms obtained with a view to statistical grouping of different cases. Cases J/K, M/O and L/P could be paired on visual appearance and Cases B/C/E/G and J/K/L/P on tablet hardness (17–23 and 80–89 N respectively). HPLC indicated that 75% of the cases examined contained diazepam but less than half of these contained the recognised amount (10 mg); Cases B/E/L/P contained phenazepam and J/K contained etizolam. The thermal signatures of individual tablets provided by DSC produced qualitative information about both drugs and excipients, indicating lactose in Cases D/F/H/I/J/K/M/N/O and Emcompress™ in B/E/L/P. In particular, DSC coupled with PCA provided confident groupings of A/C/G, B/E/L/P and H/I/J/K, and specific pairings of B/E, L/P and F/N.

U2 - 10.1039/C5AY01711D

DO - 10.1039/C5AY01711D

M3 - Article

VL - 7

SP - 8597

EP - 8604

JO - Analytical Methods

JF - Analytical Methods

SN - 1759-9660

IS - 20

ER -