Forensic drug profiling of Erimin-5 using TLC and GC-MS

Abstract

Sixty-four groups of Erimin-5 tablets from 23 sources were profiled based on their dye and active ingredients. Dye of the tablets was extracted using 5% acetic acid and subjected to TLC separation using isopropanol/ammonia (4:1) as the solvent system while the active ingredients were analysed using GCMS and diluents were analysed using FTIR. All tablets were of peach-like or green in colour. The dye components were identified as tartrazine, sunset yellow, erythrosine, ponceau 4R and brilliant blue. The active ingredients were identified as nimetazepam and diazepam with glucose, sorbitol, mannitol and lactose as diluents. The combination of dye information and chemical contents allowed a quick classification of these 23 sources into six different profiles. This drug profiling method can provide useful information for narcotic enforcement and intelligence purposes. Forensic drug laboratories receiving tablet-form Erimin-5 should perform forensic profiling a profile database of the drug.

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Malaysian Journal of Forensic Sciences, 2012, 3(1)
11
Forensic Drug Profiling of Erimin-5 Using TLC and GC-MS
aAhmad Fahmi Lim Abdullah, aAbigail Asha Abraham , bMaimonah Sulaiman and
*bVanitha Kunalan
Forensic Scienec Programme, School of Health Sciences, Universiti Sains Malaysia, 16150, Kubang kerian,
Kelantan, Malaysia
bNarcotics Section, Forensic Division, Chemistry Department of Malaysia, 46661, Petaling Jaya, Selangor,
Malaysia
ABSTRACT: Sixty-four groups of Erimin-5 tablets from 23 sources were profiled based on their dye and active
ingredients. Dye of the tablets was extracted using 5% acetic acid and subjected to TLC separation using
isopropanol/ammonia (4:1) as the solvent system while the active ingredients were analysed using GCMS and
diluents were analysed using FTIR. All tablets were of peach-like or green in colour. The dye components were
identified as tartrazine, sunset yellow, erythrosine, ponceau 4R and brilliant blue. The active ingredients were
identified as nimetazepam and diazepam with glucose, sorbitol, mannitol and lactose as diluents. The
combination of dye information and chemical contents allowed a quick classification of these 23 sources into six
different profiles. This drug profiling method can provide useful information for narcotic enforcement and
intelligence purposes. Forensic drug laboratories receiving tablet-form Erimin-5 should perform forensic
profiling a profile database of the drug.
Keywords: Erimin-5, nimetazepam, dye, active ingredients, forensic chemistry
Introduction
Erimin-5 a brand name of nimetazepam initially used
for the treatment of short-term severe insomnia in
patients. Due to worldwide abuse, nimetazepam has
been listed as a controlled substance in many
countries [1]. In Malaysia, both nimetazepam and
flunitrazepam, the two benzodiazepines are listed as
control substances under the Dangerous Drugs Act
1952. While the latter is seldom encountered, the
former tablets, either in the form of Erimin-5 or its
counterfeits, were frequently submitted to the
forensic laboratory for analysis [2].
Erimin-5 pills were frequently reported in illicit
markets in Malaysia in the mid 1980s [3]. Its wide
availability, relatively low price on the local black
markets and its long activity has made it one of the
most widely abused sedatives today. Heroin addicts
use it as a substitute and it is also increasingly used
as sedative by methamphetamine abusers after
binging [4]. Illicit manufacturing and/or illegal
smuggling of Erimin-5 is alarming. An estimated
RM9.7 million worth of Erimin-5 pills were seized
by the Royal Malaysia Police [5]. During the first
eight months of 2012 alone, Malaysia police have
seized a total of 4,115, 694 pills worth an estimated
RM80 million [5].
Drug trafficker distributed the pills through their
illicit marketing network. Therefore, profiling of
these tablets can provide useful information [6] to
help establish links among seizures [7] or to source
of origins. Dye used in the tablets could provide
useful information for forensic comparison between
pills or between pills and dyes found in clandestine
laboratories [8] or to a particular syndicate operation
while active ingredients of the tablets help establish
the chemical contents and legal status of a seizure.
Therefore, this study aims to determine the dye
components and active ingredients of Erimin-5
tablets obtained from 23 sources using routine Thin
Layer Chromatography (TLC), GCMS (Gas
Chromatography Mass Spectroscopy) and FTIR
(Fourier Transform Infrared) analyses. Establishing a
profile of these tablets may facilitate the law
enforcement operations.
Materials and methods
All chemicals used were of HPLC grade. Acetic acid
(5%), ammonia solution (3N) and iso-
proponal:ammnia (4:1) were freshly prepared. The
64 groups of Erimin-5 tablets were obtained from
seized samples from 2011-2012. Food colour
standards were obtained from The Department of
Chemistry, Malaysia.
Dye extraction and identification
Erimin-5 pills tablets were powdered using the
mortar and pestle, acidified with 5% acetic acid in a
beaker. Two knotted pieces of wool were submerged
in the mixture which was warmed on a boiling water
bath until the dye was transferred to the wool. The
wool was then removed and washed thoroughly with
water to remove other extraneous materials. The dye
on the wool was then re-extracted by warming the
wool with 5 mL of acetone and 3N ammonia mixture
(1:1) on a water bath for approximately 5 min. The
wool was then discarded and the dye extract was

Malaysian Journal of Forensic Sciences, 2012, 3(1)
12
allowed to evaporate until dry before being
reconstituted in methanol. Dye standards were
dissolved in methanol prior to TLC.
TLC separation was performed on 200 mm x 200
mm plates coated with 0.10 mm layer of silica gel.
Dye extracts and standards were spotted on the plate
using capillary tubes and developed in freshly
prepared solvent system of isopropanol/ammonia
(4:1) until the solvent front approached about 1cm
away from the top of the TLC plate. The plate was
marked and left to dry. Rf value of each band was
then calculated.
Active ingredient and diluents identification
Erimin-5 tablets from each source were pounded
with a mortar and pestle into fine powder. It is
subsequently suspended into methanol and mixed
well. The mixture was filtered and the filtrate was
analysed using GCMS (Agilent GC-MS 6890N)
equipped with an Agilent HP-5 capillary column (30
m length, 250 µm i.d., 0.25 µm film thickness) with a
flow rate of 1.2 mL/min with helium as the carrier
gas. The temperature of the injector was set at 260ºC.
The initial oven temperature was set at 250ºC for one
minute and then raised to 300ºC at a rate of 5ºC/min
and held for two minutes.
For infrared analysis, the fine powder samples were
analysed. Infrared spectra were obtained with a
Nicolet Magna-IR Spectrometer 550. The resolution
was set at 4.000 cm-1, with 32 scans between 400 cm-
1 and 4000 cm-1.
Results and discussion
TLC Analysis
All 64 groups of Erimin 5 tablets were visually
examined and grouped based on their colour. 53
groups were of peach-like colour and 11 groups were
green. Tartrazine, Sunset Yellow, Erythrosine,
Ponceau 4R and Red 2G were the standard dyes
analysed together with the dye extract from peach
coloured tablets were. Standard dyes used for
comparing the dye extracts from green coloured
tablets were Fast Green, Brilliant Blue, Green S, and
Tartrazine.
Among the 53 samples of peach-like coloured
samples, 18 contained a combination of three dyes,
namely Erythrosine, Tartrazine and Ponceau 4R to
produce the hue when the resulting bands were
compared to the retention factor (Rf) of dye
standards. The other 35 samples produced only one
band suggesting the colour from the tablets comes
from Sunset yellow. For the 11 green samples, two
bands were observed which corresponded to those
observed in the standard dyes of Brilliant Blue and
Tartrazine suggesting that the colours from all of
these tablets come from mixture of the two dyes.
Examinations on the dye composition of the 64
sample-groups from 23 sources showed that all
samples from common sources had the same
combination of dyes. This indicates that the
respective tablets could be from the same origin
hence can provide useful information to link the drug
syndicates and delineate a drug syndicate‘s illicit
market coverage.
The TLC analysis was shown to be rapid and cheap
and enabled simultaneous assay of several dozen of
tablets with satisfactory results [9]. The wool
extracting technique was effective in extracting
colouring substances from the tablets consisting of
various substances.
GC-MS Analysis
The GC parameter employed gave the peak of
diazepam at 5.546 min (Figure 1) and nimetazepam
at 6.017 min (Figure 2), with glucose at 2.455 min
and mannitol/sorbitol eluted at 2.714 min. About
82.8% (53/64) sample groups contained
nimetazepam as the active ingredient. The remaining
17.2% (11/64) groups contained diazepam as the
active ingredient.
Note that commercial Erimin-5 tablets should
contain nimetazepam as the active ingredient. From
GC-MS analysis, it was observed that the fake
―Erimin-5‖ tablets from 11 samples of three different
sources contained only diazepam as the active
ingredient. This information is important to law
enforcement personnel because only nimetazepam
and flunitrazepam are the two benzodiazepines listed
under the Dangerous Drug Act 1952.
Mannitol and sorbitol are isomers and the only
difference is the hydroxyl group on carbon 2. So, this
difference could not be detected using the GCMS
without using derivation agent, so it yields the
similar peaks for both compounds.

Malaysian Journal of Forensic Sciences, 2012, 3(1)
13
Figure 1: Gas chromatogram showing diazepam standard eluted at 5.546 min (left) and its mass spectrum (right)
Figure 2: Gas chromatogram showing nimetazepam standard eluted at 6.017 min (left) and its mass spectrum
(right)
FTIR Analysis
The FTIR analysis concluded three types of diluents
in the samples that were analysed. FTIR technique
has the capability to differentiate between the
isomers, mannitol and sorbitol. Lactose, mannitol
and glucose are the diluents identified in the samples
through this technique. About 45.3% (29/64) samples
contained lactose as the diluent. Seven (11.0%)
samples contained glucose as the diluent and
approximately 43.7% (28/64) samples contained
mannitol as the diluent.
Erimin-5 profiling
Further profiling strategy were taken by combining
the information of TLC, GC-MS and FTIR analyses
as shown in Figure 3. It shows that the results from
the three techniques enable the 64 samples for further
classification into six profiles/clusters.
Tablets from six sources contain the active ingredient
nimetazepam and lactose as diluent with a
combination of Erythrosine, Tartrazine and Ponceau
4R to provide the hue. Tablets from nine sources
contained nimetazepam, lactose and Sunset Yellow
as the dye. Nimetazepam and mannitol as ingredients
with Sunset Yellow as the colouring agent could be
found from two sources. Only one source has sample

Malaysian Journal of Forensic Sciences, 2012, 3(1)
14
which contained diazepam and mannitol as
ingredient and Sunset Yellow as the dye.
Tablets from three sources contained nimetazepam
and mannitol with a combination of Tartrazine and
Brilliant Blue to give the green colour Erimin 5.
Tablets from two sources contained diazepam as
active ingredient, glucose as diluent and mixture of
Tartrazine and Brilliant Blue as the colouring agent.
Obviously, this simple profiling strategy could aid
law enforcement operations who seized samples at
different locations to link the source to its syndicate
operation or source of illegal productions. Further
profiling could also be made if more physical or
chemical information could be generated.
Figure 3: Bar chart shows the distribution of active ingredient, diluent and dyes according to number of sample
groups (ETP = erythrosine, tartrazine and ponceau 4R, SY = sunset yellow, and TB = tartrazine and brilliant
blue)
Conclusion
A framework of the Erimin-5 tablets profiling based
on dye identification by TLC with active ingredient
identification using GCMS and diluents
identification using FTIR was developed. All the
three analyses gave useful results, which were then
used to compare the tablets from different sources.
This rapid and cost effective drug profiling method
can be easily adapted for forensic narcotic
laboratories that normally receive Erimin-5 in tablet
forms and could be used as routine laboratory
procedure to build a drug profile database for
investigative and intelligence purposes.
Acknowledgement
We thanked The Chemistry Department of Malaysia
for their advice and cooperation.
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Malaysian Journal of Forensic Sciences, 2012, 3(1)
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Additional information and reprint requests:
Vanitha Kunalan
(Email: vanitha@kimia.gov.my)
Forensic Division
Chemistry Department of Malaysia
Jalan Sultan
46661, Petaling Jaya
Selangor, Malaysia