Conclusions The Future of Drugs Poisons and chemistry

The world of forensic chemistry—illicit drugs and poisons in particular—never stands still. There will always be a race between those making and using illegal drugs and those working to detect, analyze, characterize, and control them. Illicit drugs go through cycles of birth, popularity, and decline. In the 1990s cocaine was a major concern; now it is methamphetamine. In 2020 it will be something else. What remains constant is the need for society to define what drugs it will control and for forensic chemistry to develop the analytical methods to analyze these drugs and poisons. Given this underlying reality, the future of forensic drug analysis and toxicology is very much tied to advances in analytical chemistry and the instruments used to conduct it.

Each year brings greater improvements in the capability, automation, and portability of chemical instrumentation. These advances trickle down to forensic chemistry and forensic biology, increasing throughput (number of samples that can be run in a day) and decreasing turnaround time. Soaring caseloads at laboratories often overwhelm these improvements. Yet, without these improvements crime laboratories would be quickly inundated. Autosamplers, which allow instruments to run unattended, have been a boon for drug analysis and toxicology, where much of the analysis requires instrumental data. Robotics systems are now capable of automating many of the tasks of sample preparation and transfer. While instruments and accessories cannot replace a forensic chemist, toxicologist, or biologist, automation maximizes the productivity of each, allowing the scientist to concentrate on analysis and interpretation.

New instrumentation and improved design of older instruments is also influencing forensic analysis. Much of this can be traced to decreasing costs as technologies mature. Many labs now use HPLC and HPLC-mass spectrometry (HPLC-MS), techniques that were rarely seen in forensic labs until the 1990s, both due to cost and method development considerations. HPLC-MS combines the separation power of high-performance liquid chromatography with the ability of mass spec-trometry to identify definitively most molecules of interest to forensic chemists. The newest generation of HPLC-MS instruments actually consists of multiple mass spectrometers chained together, dramatically increasing the sensitivity and selectivity of the instrument. As a result forensic toxicologists may soon be able to detect many more drugs and metabolites at much lower concentrations than they could previously. This ability will be invaluable in many cases, such as when a person dies of subtle drug interactions or from poisoning by trace containments of clandestinely produced drugs.

A workhorse instrument in forensic chemistry, the IR spectrophotometer has seen advances in capability that will likely continue unabated. The driving force of much of this improvement lies with advancement in lasers and electronics. For inorganic analysis instruments such as the inductively coupled plasma mass spectrometer (ICP-MS) and inductively coupled plasma atomic emission spectroscope (ICP-AES) are expanding into forensic labs and will likely become commonplace in the next 10 to 20 years. These instruments allow for low-level detection of metals such as arsenic, chromium, and other potential poisons. Likewise, surface analysis instruments such as X-ray fluorescence (XRF) and scanning electron microscopes (SEM) are becoming affordable to more forensic labs, increasing capabilities and enlarging the scope of analyses available to the forensic examiner.

Finally, the world of genetics and forensic toxicology are starting to overlap, and the implications for forensic toxicology are likely to be significant. When a person takes a drug, enzymes are involved in the metabolism of that drug. Enzymes are proteins that are produced from genetic instructions encoded in that person's DNA. Many of the genes that code for enzymes are polymorphic, meaning that one person's version of the enzyme may be slightly different from another's. How these enzymes vary is inherited just as is eye color and blood type. The implication is that different people, because they have different versions of enzymes, will metabolize drugs and poisons differently. A person who efficiently metabolizes a drug could tolerate a higher dose than a person whose metabolism is less efficient. Thus, the lethal dose of drugs and drug combinations will vary. The study of genetic effects on drug metabolism is called pharmacogenetics, and it is likely to become an important aspect of forensic toxicology in the next 20 years.

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