Adulterants and interpretive challenges in forensic science: Effects on colorimetric spot tests for presumptive drug identification and adverse side effects in the body.

摘要

A common practice amongst street drug manufacturers and dealers is to combine the illicit drug of abuse they intend to distribute with additional substances. Substances added in an attempt to mimic or enhance the desired effect of the drug of abuse are known as adulterants as opposed to diluents, which are added simply to increase the weight of the product. By definition, an adulterant has a physiological effect on the body and as physiologically active compounds these adulterants may have side effects apart from the drug it is added to. They can be minimal, treatable, or otherwise manageable while others can be worse than those incurred from the drug of abuse itself.;Due to varying trends in street drug purity, an effort must be made to understand the effects adulterants and diluents, as well as mixtures thereof, may have on forensic drug analysis. Colorimetric spot test analysis is typically performed using a representative sample of the raw, suspected drug material. These tests are often employed in the lab prior to any attempt to isolate a specific compound or at the scene before an arrest is made. This being the case, the reagents will be exposed to and have the potential to react with anything present in the sample with the drug of abuse. While much work has been done regarding the specificity and cross reactivity of colorimetric spot tests, limited information is available about how mixtures of adulterants may affect the results.;This research consists of two parts which approach the common theme of adulterants differently. The first part is a literature based investigation into the pathological side effects of several common drug adulterants. The specific compounds discussed are: levamisole, phenacetin, atropine, and several topical anesthetics (benzocaine, lidocaine, prilocaine, and procaine). A review of articles from the scientific literature was conducted in order to convey what is known in the medical field regarding the effects these compounds can have on the body. The second part of this research was a laboratory based investigation which analyzed the effects of twenty-three common adulterants on two colorimetric spot tests: the Marquis reagent for the presumptive identification of heroin, morphine, amphetamine, methamphetamine, and 3,4-methylenedioxy-N-methamphetamine (MDMA) and the modified Scott test for the presumptive identification of cocaine. This was performed in order to observe the reactivity of these compounds so that a better understanding of the effect their presence can have on the analysis of seized drug samples using these tests could be obtained.;The literature review portion of this research revealed that the adulterants levamisole, atropine, phenacetin, and the topical anesthetic adulterants lidocaine, prilocaine, benzocaine, and procaine, can be toxic and have severe, deleterious effects on the body in both chronic and acute exposures. Levamisole stimulates the immune system resulting in the production of self-reactive antibodies that attack neutrophils. This causes an autoimmune disorder that weakens the immune system and causes leukocyte agglutination leading to necrotizing vasculitis. Atropine functions to decrease the parasympathetic tone and increase the sympathetic tone in the body. An overdose can cause anticholinergic toxicity, a syndrome very similar to sympathomimetic toxidrome caused by cocaine overdose. Both are characterized by hypertension, hyperthermia, tachycardia, ataxia, disorientation, and mydriasis. However, they can be distinguished as anticholinergic toxicity causes dry and flush skin and mydriasis which is unreactive to light while sympathomimetic toxidrome causes profuse sweating and mydriasis which is reactive to light. Phenacetin is metabolized to O-ethyl-N-acetyl-p-benzoquinone imine (O-Et-NAPQI), a highly reactive and unstable electrophile. It is capable of covalently binding with proteins and other cellular components, including deoxyribonucleic acid (DNA). This leads to mutagenesis and subsequent tumor generation as well as apoptosis and necrosis of various tissues in the bladder and kidneys. The topical anesthetics have each been associated with the development of methemoglobinemia. This is a condition caused by an increase in the concentration of methemoglobin in the blood. Methemoglobin binds more strongly to oxygen so that it cannot be released to the tissues resulting in oxygen starvation. This was found to be caused by the metabolism of prilocaine and lidocaine to the oxidative compounds O-toluidine and 2,6-xylidine respectively. The cause has not been previously reported for benzocaine or procaine. (Abstract shortened by UMI.).