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5. analytic and forensic toxicology
1. BULE HORA UNIVERSITY
COLLEGE OF HEALTH AND MEDICAL
SCIENCES
DEPARTMENT OF PHARMACY
TOXICOLOGY
For 4th year Medical Laboratoy Students
Principle of Analytic Toxicology 1
By:Aliyi G.(B.Pharm)
2. 2
5.Principles of Analytic
Toxicology
. Applications in general and forensic
toxicology and clinical practice
. Interpretation of analytic results
Principle of Analytic Toxicology
3. 3
Analytic Toxicology
The detection, identification & measurement of
foreign compounds (xenobiotics) in biological &
related specimens.
Involves application of the tools of analytic chemistry
to the qualitative or quantitative estimations of
chemicals
that may exert adverse effects on living organisms.
is the only means by which objective evidence of the
nature & magnitude of exposure
1. Introduction
Principle of Analytic Toxicology
4. Introduction Cont’d,...
4
Forensic Toxicology
The use of toxicology for purposes of the law.
To identify any chemical that may serve as a
causative agent in inflicting death or injury/damage
on humans/property.
Principle of Analytic Toxicology
5. Introduction Cont’d,...
5
Separation is more often a prerequisite for analytical determination.
Gases
Volatile Substances
Corrosive Agents
Metals
Anions and Nonmetals
Nonvolatile Organic Substances
Miscellaneous
Principle of Analytic Toxicology
7. 1. Role in General Toxicology
7
Ascertaining purity of a chemical or contaminants of chemical to be
studied
The chemical under study must be pure or the nature of any contaminant
must be known to interpret experimental results with validity.
Monitoring dosage forms or solutions for stability throughout the
course of an experimental study.
Important in establishing the bioavailability of a compound under
study
Rather than observing dose-effect r/n ships ,
Principle of Analytic Toxicology
8. 2. Analytic Role in Clinical Toxicology
8
Used to
identify the nature of the toxic exposure and
measure the amount of the toxic substance that
has been absorbed.
monitoring the amount of the toxic agent
remaining in circulation or measuring what is
excreted.
Important in establishing
a diagnosis of poisoning &
guiding treatment
Principle of Analytic Toxicology
9. Importance
9
Both the identity/nature & amount of toxic s/ce
– aid in diagnosis, t/t, monitoring the effectiveness of t/t
regimens.
Nature & amount coupled by information on the clinical state
permits to relate the signs & symptoms observed to the anticipated
effects of the toxic agent.
Principle of Analytic Toxicology
10. Most commonly encountered drugs & methods for
analysis in emergency toxicology
Rank Drug Specimen Analytical method
1 Drugs of abuse urine immunoassays
2 ethanol serum GC
3 benzodiazepins Urine/serum Immunoassay or
GC
10
Principle of Analytic Toxicology
11. 3. Analytic Role in Therapeutic Monitoring
11
Factors responsible for individual variability in responses to drug
therapy include:
Rate and extent of drug absorption
Distribution and binding in body tissues and fluids
Rate of metabolism and excretion
Pathologic conditions
Interaction with other drugs
Monitoring of the plasma or serum conc.
at regular intervals will detect deviations &
suggest that one or more of these of variables need to be identified
& corrected.
Principle of Analytic Toxicology
12. 4. Analytic Role in Biologic Monitoring
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Monitor workers directly for exposure
Exposures are to a mixture of compounds.
Measure changes of normal metabolites induced by
xenobiotics.
eg. the profile of glucouronic acid metabolites excreted
in urine can be altered after exposure to substance
that induce monoxygenase activity..
Principle of Analytic Toxicology
13. 5. Role in Forensic Toxicology
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Postmortem Investigations
Qualitative & quantitative analysis of drugs/poisons
in biological specimen collected.
+
Interpretation of analytic finding in regard to
physiologic & behavioral effects.
NB: many drugs or poisons do not produce
characteristic pathologic lesions;
their presence in the body can be demonstrated
only by chemical method of isolation &
identification Principle of Analytic Toxicology
15. Application of forensic toxicology
Cause of death in .
Assist in cause of death for a court of law.
Presence of intoxicating concentration of ethanol in car accidents.
Carbon Monoxide detection in fire victims.
Provide data for substance abuse.
Principle of Analytic Toxicology
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16. 1. Toxicological Investigation of a Poison Death
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3 steps
1. Obtaining case history and suitable specimens
2. Toxicologic analyses
3. Interpretation of Analytic findings
Principle of Analytic Toxicology
17. 1.1. Case History and Specimens
17
Collect facts (age, sex, wt, medical history, occupation, t/t
administered before death).
Gross autopsy findings.
Drugs available to the decedent.
Interval between the onset of symptoms and death.
Principle of Analytic Toxicology
18. 1.2. Toxicologic Analyses
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Factors to consider
Amount of specimen available
Nature of the poison
Possible biotransformation of the poison
Eg.cocaine.
Principle of Analytic Toxicology
19. Toxicologic Analyses…
19
In case of involving oral administration of the poison
Organs Analyzed
1st Gastrointestinal contents (residual unabsorbed
poison found )
2nd Urine (high conc. of toxic s/b &its metabolites)
Liver….1st internal organ analyzed
Specific poison is suspected to have caused or
contributed to a death, the tissue & fluids in which
the poison concentrates
Principle of Analytic Toxicology
20. Toxicologic Analyses…
20
The analysis (the autopsy & toxicological) should be
started soon after death.
Problems:
Hydrolysis, oxidation or reduction of proteins,
nucleic acids, or lipids that may generate compounds
that interfere with identification.
Principle of Analytic Toxicology
21. Toxicologic Analyses…
21
Testing
Non-specific test
Ferric chloride, perchloric and nitric acid color test for
phenothiazine drugs and
immunoassays for the detection of amphetamines,
benzodiazepines and opiates in the urine.
Specific test
GC or HPLC is most widely used for most drug identification.
Principle of Analytic Toxicology
22. 1.3. Interpretation of Analytic Results
22
Provides answers
Route of Administration
Dosage and if conc. of toxicant present is enough to
cause death or alter action enough to cause death.
Tests on blood, tissue, and plasma
Results are often used to corroborate investigative
findings
Eg. Continuously elevated hair arsenic values indicates
chronic rather than acute poisoning as the cause of
Principle of Analytic Toxicology
23. Interpretation of Analytic Results…
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A new extension of forensic toxicology
is the analysis of impurities of illicit drug synthesis in biological
specimens.
Eg. Methamphetamine
Principle of Analytic Toxicology
24. 2. Criminal Poisoning of the Living
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GC or HPLC tests are used for 2 types of poisoning
Administration of drugs to incapacitate victims of
kidnapping, robbery, or sexual assault.
Eg. Ethanol, BDZ, marijuana, amphetamine, opaites etc
Poisoning as a form of child abuse;
deliberate administration of toxic or injurious substances to a
child, usually by a parent or other caregiver
Eg. Syrup of ipecac, table salt, laxative, diuretics, narcotics etc
Principle of Analytic Toxicology
25. 3.Forensic Urine Drug Testing
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Urine tested for a limited number of drugs.
Sample is checked for adulteration
by checking the
pH,
creatine,
specific gravity and
for any unusual color or smell.
Principle of Analytic Toxicology
26. Forensic Urine Drug Testing…
26
There may be valid reasons other than
substance abuse for positive drug findings
eg. Poppy seed (papaver somniferum) is
common ingredeint in many pastries & breads.
poppy seeds may contain significant
amounts of
morphine.
Morphine is a major metabolites of heroin,
to readily differentiate heroin abuse from
poppy seed ingestion,
analysis may be performed for 6-
Principle of Analytic Toxicology
27. 4. Human Performance Testing
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Tests for ethanol and chemicals in blood, breath
or other specimens that may modify performance
of behavior.
Alcohol related accidents are responsible for
55-65% of fatalities in drivers
Principle of Analytic Toxicology
28. 5. Courtroom Testimony
Lay(uncertified) witness Vs expert witness
Toxicologist
an expert witness providing an objective testimony and opinion.
Objective~ Involves description of his or her analytic methods and
findings
Opinion~how the person interprets the results.
Principle of Analytic Toxicology
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