Brain-to-blood ratio
statistic in pharmacokinetics
The brain-to-blood ratio, or brain–blood ratio, is a statistic in pharmacokinetics defined as the ratio of a drug's brain concentrations relative to its circulating blood concentrations. It is a measure of the ability of a drug to cross the blood–brain barrier and exert effects in the central nervous system.
Determinants of brain-to-blood ratio include physicochemical properties like molecular volume, molecular weight, polar surface area, charge state, hydrogen bonding (related to quantity of nitrogen and oxygen atoms), and hydrophilicity–lipophilicity. Other factors include plasma protein binding, active transport across the blood–brain barrier either into the brain or out of the brain by membrane transport proteins (transporters), and degree of binding to components of brain tissue.
An example of brain-to-blood ratio can be made with beta blockers. The highly lipophilic beta blocker propranolol has a brain-to-blood ratio in humans of 15:1 to 26:1, whereas the hydrophilic beta blocker atenolol is peripherally selective with a blood-to-brain ratio of 0.2:1.
The public source identifies “Brain-to-blood ratio” as statistic in pharmacokinetics. This brief keeps that definition visible, then builds a research path around Brain-to-blood, ratio and statistic.
Why this record matters
A short description can identify a subject without explaining its stakes. For “Brain-to-blood ratio”, the useful work is to connect “statistic in pharmacokinetics” to the records capable of establishing context and consequence.
Named sources, stable identifiers and responsible institutions provide the strongest route from overview to verifiable evidence. The source revision retrieved here is dated Feb 28, 2026. The linked authority identifier is Q135466797. None of the 0 selected statements returned an explicit reference.
A concise general-reference account can conceal disagreements about scope, terminology or the weight assigned to individual sources. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Use the entry as an orientation point, then follow its citations and revision history. Names, dates and institutional relationships should be checked against the original record.
- Subject orientation
- Search vocabulary
- Locating named sources
The closest primary source, responsible institution and strongest cited specialist reference.
Three-step research path
- Establish the record: confirm the title “Brain-to-blood ratio”, its source revision and the description used here.
- Expand the search: follow Brain-to-blood ratio primary sources, Brain-to-blood ratio archive and Brain-to-blood research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “Brain-to-blood ratio”?
- Which cited source is closest to the event, object or claim?
- Which institution is responsible for the underlying evidence?
Search terms from this dossier
This entry incorporates text from “Brain-to-blood ratio” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.