Forensic Toxicology Flashcards
What is the purpose of drug use Missuse Act (1971)
-means for control of all drugs
-grade penalties for misusing drugs
-brings new substances under control
-restricts prescription of drugs
-Established ACMD
What are the different classes of drug ?
A,B,C
What is the highest class of drug ?
Class A
What drugs come under class A ?
Cocaine and crack, ecstasy, heroin, LSD, methadone, methamphetamine and magic mushrooms
Which class A drug might be prescribed?
Methadone is prescribed to heroin addicts
What drugs are in class B?
Medical use: amphetamine, barbiturates, codeine, ketamine
recreational: spice, cannabis, mephedrone, methylone and methedrone, MDPV
What drugs are in class C?
Anabolic steroids, minor tranquilizers or benzodiazepines, GBL and GHB, Khat and BZP
How is possession of drugs divided ?
-possession for individual use
-possession with intent to supply
How is possession for individual use determined ?
Weight
How is the possession of drugs usually prosecuted ?
Usually prosecuted with another crime
What is the offence range for category 1(class A) ?
Maximum: 7 years
Range: fine- 51 weeks custody
What is the offence range for category 2 (class B) ?
maximum: 5 years
Range: Discharge-26 weeks custody
What is the offence range for category 3 (class C) ?
Maximum: 2 years
Range: discharge- community order
What is the offence range for possession with the intent to supply for Class A ?
Maximum: life
Range: community order- 16 years custody
What is the offence range for possession with the intent to supply for Class B ?
Maximum: 14 years
Range: fine- 10 years custody
Who would get a fine for possession of drugs with intent to supply of class B ?
Street level dealers
What is the offence range for possession with the intent to supply for Class C?
maximum: 14 years
Range: fine- 8 years custody
What is the first step in determining sentencing for possession with intent to supply ?
Determining the offence category
How does the court determine the offence category ?
Determine the offender’s culpability and harm caused
how does the court assess culpability ?
Weight up all the factors of the case to determine role and balance the characteristics to make a fair assessment
How does the court assess harm ?
Weight of the product. Purity isn’t taken into account
What is a leading role ?
- directing/ organizing on a commercial scale
-link to others in a chain
-close link to original source
-expectation of substantial financial gain
-uses business as a cover
-abuses a position of trust or responsibility
What business is typically used as a cover for drug dealing ?
Car dealership
What is a significant role ?
-operational/management function
-involves others by pressure, intimidation or reward
-motivated by financial gain
Some awareness and understanding of scale of operation
What is a lesser role ?
-perform a limited function
-engaged by pressure
-involved through exploitation
-no influence
-very little awareness
-absence of financial gain
What is county lines ?
using vulnerable people (children) to smuggle drugs across county borders
What is the weight of drugs in category 1 ?
Heroin/cocaine- 5kg
Ecstasy- 10,000 tablets
LSD- 250,000 squares
Amphetamines- 20kg
Cannabis-200kg
Ketamine-5kg
What is the weight of drugs in category 2?
Heroin/cocaine- 1kg
Ecstasy- 2,000 tablets
LSD- 25,000 squares
Amphetamines- 4kg
Cannabis-40kg
Ketamine-1kg
What is the weight of drugs in category 3?
Heroin/cocaine- 150g
Ecstasy- 300 tablets
LSD- 2500 tablets
Amphetamines- 750g
Cannabis- 6kg
Ketamine-150g
What is the weight of drugs in category 4?
Heroin/cocaine- 5g
Ecstasy- 20 tablets
LSD- 170 squares
Amphetamines- 20g
Cannabis-100g
Ketamine-5g
Why is the Uk an attractive market for drug dealing ?
Due to high street price, diverse ethnicity and major transport hubs
What were the NCA drug seizures in 2016 ?
69.8 tonnes of cocaine
4.5 tonnes of heroin
123.1 tonnes of cannabis
How much of the UK drug trade does the 2016 seizures represent ?
<2%
Where do illicit drugs in the Uk originate ?
- grown overseas and imported- cocaine, cannabis resin and heroin
-grown within the UK- cannabis (75%)
-synthesized within the UK or Europe- MDMA
What are the major trafficking routes into the UK for illicit drugs ?
- Cannabis: North Africa via Spain
- Heroin: typically originates from the golden crescent and enters via turkey
- Cocaine- originates in S.America and enters through Africa and Spain
Where does the majority of heroin in the UK originate ?
90% originates from the golden crescent
Where does the remainder of heroin come from?
SE Asia the golden triangle
What is the difference between afghan heroin and SE Asia heroin ?
SE Asia- white, high purity (80%), contains diamorphine hydrochloride and a few other opium alkaloids
SW Asia- cruder product, brown, 50% purity, contains diamorphine base and significant amount of noscapine
Where does cocaine originate ?
central and Northern America
How is cocaine transported ?
Body packers
What are body packers ?
The consumption of drugs for transportation within the body
What is used to transport the drugs in body packing ?
Drugs may be placed in condoms or in packets enclosed by several layers of polyethylene or latex
Why do body packers take anti-motility drugs ?
Reduce bowel movement
What is the risk of body packing ?
the total amount for drugs involved resents a super lethal dose, rupture of one or more packets is a risk and can result in abrupt toxicity or overdose
Who is often used as body packers ?
Pregnant women as it’s illegal to subject them to X-Rays due to radioactivity
What type of cannabis do cases usually involve ?
Skunk cannabis
What yield do plants submitted from grow rooms typically have ?
45g or 90g per plant
What is the sequence for testing illicit drugs ?
-drug sample
-physical description
-sampling- typically 10%
-presumptive tests (colour change test)
-quantification
-expert report
What are the two different types of analysis carried out ?
Presumptive and confirmatory
What are the different confirmatory tests ?
-UV
-IR
-GC-MS
When is purity testes ?
On request or if it is a large consignment of drugs
What is the marquis test ?
capable of detecting most opium based drugs such as heroin, morphine and MDMA
What does the marquis test consist of ?
A mixture of formaldehyde and sulphuric acid
How does the marquis test detect opiates ?
A violet colour is obtained from the formation of an oxonium ion after dimerizarion of 2 molecules of formaldehyde and opiate
how does the marquis test detect MDMA ?
Orange colour is obtained from the formation of a central carbonic
What is the cobalt thiocyanate test used for ?
Cocaine
What colour does the cobalt thiocyanate test turn in the presence of cocaine ?
Blue
What does the cobalt thiocyanate test contain ?
CT, glycerin, HCL and chloroform
What does the Duquenois-Levine test for ?
Cannabis
What does the Duquenois-Levine test contain ?
Vanillin, acetaldehyde, HCL and ethanol
What colour does Duquenois-Levine test turn in the presence of cannabis ?
Purple
how does thin layer chromatography work ?
-A series of drugs (known) are spotted on the plate and is stood in a shallow layer of solvent in a covered beaker.
-the atmosphere in the beaker is saturated with a solvent vapour
-The solvent will rise up through the plate and separate drugs into its multiple spots at different locations on the plate
How is Rf calculated ?
Distance travelled by component/ distance travelled by solvent
How does IR work ?
Obtained by measuring the interaction of IR radiation with a drug structure. A molecules absorbance of IR is unique to its structure so each molecule can give its own unique IR spectrum.
What is the fingerprint region ?
the most complex IR spectrum, this is the region with the most structural selectivity and thus it is this region that is ued separate individual drugs from the same classes
What is the issue with a spike in purity ?
more likely to Overdose
Why is Benzocaine the most common cutting agent ?
cocaine was originally a dental anesthetic so makes it appear more pure to some
What are the major factors of growing cannabis plants ?
-sex of plant
-light exposure
-flowering yield
-natural selection
How have Yorkshire produced higher yield plants ?
-better seeds
-better light
-better agricultural knowledge
how many hours of light does a cannabis plant need in the vegetative phase ?
24 hours
how many hours of light does a cannabis plant need in the flowering phase ?
12 hours produces the highest yield
What is a poison ?
Doris sola facit venenum= ‘only the dose makes a poison’
Poison refers to how lethal the drug is
What are different types of poisoning cases ?
-self poisoning
-acute poisoning
-fatal poisoning
-munchausen syndrome/ munchausen syndrome by proxy
-chronic/ acute on chronic substance abuse
-occupational/ environmental
-mediated (poisoning scares)
What is Münchausen syndrome/ Münchausen syndrome by proxy ?
Münchausen syndrome- making yourself sick for attention
Münchausen syndrome by proxy- inflicting harm on others to look after them for attention/ gratification
What is LD50 ?
Refers to the dose of a substance that kills half the test population, usually within 4 house. Typically expressed mg of substance per kg of body weight
How many tablets would be needed to kill someone that weighs 70kg if the LD50 of paracetamol is 2000mg/Kg ?
70x 2000= 140,000
140,000/500mg tablet= 280 tables
What is considered extreme toxicity ?
<1 mg/kg
What are the symptoms of caustic poison (lye) ?
Characteristic burns around the lips and mouth of victim
What are the physical symptoms of carbon monoxide poisoning ?
Red or pink patches on the chest and thigh, usually bright red lividity
What are the symptoms of acid poisoning ?
Sulfuric acid= black vomit
Hydrochloride acid= greenish-brown vomit
Nitric acid= yellow vomit
What are the symptoms of phosphorus poisoning ?
Coffee-brown vomit, onion or garlic odor
What are the symptoms of cyanide poisoning ?
Burnt almond odor
What are the symptoms of metal poisonings (arsenic, mercury) ?
Extreme diarrhea
What are the symptoms of methyl or isopropyl alcohol poisoning ?
Nausea and vomining, unconsciousness, possibly blindness
What is the most common form of poisoning in the UK ?
Carbon monoxide
How does carbon monoxide affect the body ?
Binds to haemoglobin with a 230x greater affinity than O2
-causes competition between CO and O2 for binding sites
-as CO binds with greater affinity and lower concentration is needed to saturate haemoglobin
-this causes tissues to become starved of oxygen leading to anaerobic respiration
What is the prevalence of CO poisoning ?
-decline in early 60s due to replacement of coal
-gas with natural gas that has lower CO content
-increase in males from mid 80s due to suicides
-introduction of catalytic converters caused decline in 90s
What are diagnostic features of CO poisoning ?
-more than one person in house is affected
-symptoms related to cooking
-symptoms worse in winter (heating in greater use)
-symptoms ameliorate on holiday but recur on return
-some groups (elderly, babies, pregnant women) more susceptible to CO toxicity
-symptoms similar to influenza
What is cyanide ?
A rapidly acting, highly toxic chemical that may come as a gas or crystal salt form
What is cyanide in its gaseous form ?
Hydrogen cyanide or cyanogen chloride
What is cyanide in its crystal form ?
Sodium/ potassium cyanide
How does cyanide affect the body ?
- binds to the same heme group as O2 blocking it from binding
-O2 is not reduced, interrupting ATP production causing death
What is the main toxicity following paracetamol poisoning ?
-acute liver injury which results from the formation of a toxic metabolite of paracetamol (NAPQI)
What happens when a therapeutic dose of paracetamol is taken ?
- paracetamol is metabolized into 2 major non-toxic metabolites- sulphate and glucuronide conjugates- which accounted for 30% and 55% of paracetamol metabolism
-NAPQI is formed in small amounts and is detoxified by irreversible glutathione-dependent conjugation reactions to two non-toxic metabolites
What is NAPQI ?
It’s a highly toxic metabolite formed by cytochrome P450 2E1 and is responsible for the hepatocellular injury that occurs with paracetamol toxicity
What happens in paracetamol overdose ?
The increased formation of NAPQI depletes glutathione and binds to critical cellular proteins of the liver resulting in hepatic cell death
What is warfarin ?
Used as an oral anticoagulant to minimize the risk of blood clotting in the veins of patients
Why is warfarin dosage closely monitored ?
to ensure that the INR does not rise above 2-3 because if it does the patient risks a bleed of the brain
What else can be used to determine drug intake ?
Hair
How should hair samples be collected ?
- hair should ideally be taken from the posterior vertex region of the head
-two specimens each of approximately the thickness of a pencil should be taken
-the hair sample should be tied in some fashion
-cut as close to the scalp as possible
-samples should be labeled in such a fashion that it is easy to identify the proximal and distal ends of the hair
-should be stored dry at room temperature
What are issues with hair testing ?
-the rate of growth of hair is variable
-time for the hair to emerge from the skin is variable
-how close the hair has actually been cut to the scalp
-has the hair been cut at an angle ?
-drugs can be washed out of hair over time
-contamination (sebum, sweat, environment, hair treatment)
What is the average rate of hair growth used ?
1cm/month
What is haloperidol?
neuroleptic antipsychotic that is used for the treatment of acute and chronic psychotic states, anxiety, paranoid delusions and hallucinatory psychoses
What is a calibration curve ?
Estimates the conc of an unknown value
What is the R squared of a calibration curve ?
Correlation coefficient
What is a perfect correlation coefficient ?
1
What should the correlation coefficient be for it to be acceptable to use in forensics ?
> 0.990
What are quality control samples ?
Spikes blood samples at specific concentrations
What does the QC have to be for it to be accepted ?
Within 20% of the target
What is the Q1 of mass spectrometry ?
-4 rods
-acts as a filter
- looks at molecular weight of drug
What is Q2 of mass spectrometry ?
- wall of gas (nitrogen or helium)
-smash ions against wall
-molecular weight breaks down
What is Q3 of mass spectrometry ?
-4 rods
-looks at molecular weight
