Microdosing
Microdosing, or micro-dosing, involves the administration of sub-therapeutic doses of drugs to study their effects in humans, aiming to gather preliminary data on safety, pharmacokinetics, and potential therapeutic benefits without producing significant physiological effects. This is called a "Phase 0 study" and is usually conducted before clinical Phase I to predict whether a drug is viable for the next phase of testing. Human microdosing aims to reduce the resources spent on non-viable drugs and the amount of testing done on animals.
Less commonly, the term "microdosing" can be used to refer to precise dispensing of small amounts of a drug substance for a drug product and, when the drug substance also happens to be liquid, this can potentially overlap with the term microdispensing.
Techniques
The basic approach is to label a candidate drug using the radio isotope carbon-14, then administer the compound to human volunteers at levels typically about 100 times lower than the proposed therapeutic dosage.As only microdose levels of the drug are used, analytical methods are limited. Extreme sensitivity is needed. Accelerator mass spectrometry is the most common method for microdose analysis. AMS was developed in the late 1970s from two distinct research threads with a common goal: an improvement in radiocarbon dating that would make efficient use of datable material and that would extend the routine and maximum reach of radiocarbon dating. AMS is routinely used in geochronology and archaeology, but biological applications began appearing in 1990 mainly due to the work of scientists at Lawrence Livermore National Laboratory. AMS service is now more accessible for biochemical quantitation from several private companies and non-commercial access to AMS is available at the National Institutes of Health Research Resource at Lawrence Livermore National Laboratory, or through the development of smaller affordable spectrometers. AMS does not measure the radioactivity of carbon-14 in microdose samples. AMS, like other mass spectrometry methods, measures ionic species according to mass-to-charge ratio.
Psychedelic
Davivid Rose invented the word "microdose" in 1980 to describe a 5 microgram dose of LSD."If the story about 'Clearlight Brand "microdose" LSD' is true, then the origin of the term 'microdose' for very small doses of LSD precedes all other uses of the term, e.g. in pharmacology, in agriculture and by Fadiman."
---German psychiatrist Torsten Passie, in his 2019 book The Science of Microdosing Psychedelics, published by Psychedelic Press. The book reproduces a page of the product information leaflet for "Clearlight brand 'microdose' LSD" that Davivid Rose wrote and distributed in early 1988.
The first publicly published mention of microdose LSD was in "LSD Doodles--Catalogue Number One" by Hank Exclamation Point, a 1991 coloring book for adults that was published by Exploding Mandala Press in Berkeley, California in a very tightly-controlled limited edition. Each copy came with a set of color pencils, a pencil sharpener, and a packet containing 25 doses of Clearlight brand "Microdose" LSD. Each copy of the coloring book had a copy of the product insert that came with each packet bound into it.
The first large batch of microdoses Davivid Rose produced was made in Berkeley in 1980 from LSD he illegally purchased from an underground source. He called them "Clearlight brand Mind Vitamin Tablets" and packaged them in labeled shrink-wrapped brown glass bottles, each containing 100 tablets. Each tablet contained 100 milligrams of ascorbic acid and 5 micrograms of LSD. This first large batch of microdose LSD was given away, not sold
Davivid Rose manufactured a second labeled batch of microdoses in early 1988. Each 25-dose package of this second batch was distributed with a product information leaflet reading “Clearlight brand 'microdose' LSD". The LSD in this second labeled batch of microdoses was said to have been legally synthesized by a commercial lab for use as comparative samples by law enforcement and medical labs. Davivid Rose put it on perforated paper. More than 400,000 doses were manufactured. Most of this second batch was seized by Drug Enforcement Administration agents in Oakland, California in early January 1993. No one was arrested. The portion of the second batch that was distributed was given away, not sold.
Psychedelic microdosing is the practice of using sub-threshold doses of serotonergic psychedelic drugs in an attempt to improve creativity, boost physical energy level, emotional balance, increase performance on problem-solving tasks and to treat anxiety, depression and addiction, though there is very little evidence supporting these purported effects as of 2019.
Impact of psychedelic microdosing
In 2021 it was reported in a study done that an increased conscientiousness was seen due to microdosing. Microdosing was seen to have improved mental health after microdosing with psychedelics after 30 days. More research is needed to ultimately decide whether or not microdosing helps those who suffer from depression and anxiety. Microdosing has not seen to improve participants motor responses, attention, and cognitive problem-solving abilities. Microdosing is still under investigation as to whether it works or not. Researchers are investigating into microdosing more and more, the placebo effect causes difficulties in research on this topic.In January 2006, the European Union Microdose AMS Partnership Programme was launched. Ten organizations from five different countries will study various approaches to the basic AMS technique. The study is set to be published in 2009.
One of the most meaningful potential outcomes of Phase-0/Microdosing studies is the early termination of development. In 2017, Okour et al published the first example in literature of a termination of an oral drug based on IV microdose data.