Zaleplon
Zaleplon. Z-drug pyrazolopyrimidine — positive allosteric modulator at GABA-A BZD site, selective for α1 subunit. Used for sleep onset (very… Oral half-life 1.1 h.
Z-drug pyrazolopyrimidine — positive allosteric modulator at GABA-A BZD site, selective for α1 subunit. Used for sleep onset (very short t½ ~1 h limits middle-of-night dosing risk). Mostly metabolized by aldehyde oxidase + CYP3A4. Rapid absorption.
PK: THE BEST-SOURCED RECORD IN THIS BATCH, and it is recorded as such. Its half-life, volume and bioavailability all trace to one true intravenous-and-oral crossover, the half-life is the INTRAVENOUS value and therefore a genuine disposition parameter, and the volume is a steady-state figure from that same intravenous arm — so pairing it with the measured bioavailability is CORRECT, not the double-division it superficially resembles. Only ka 1.5 fails, appearing nowhere; the paper says merely that absorption was "rapid", and it is dropped rather than invented. A CAVEAT IS ADDED TO THE EFFECT-COMPARTMENT VALUE, WHICH ITSELF VERIFIES EXACTLY: its quote and arithmetic are both right, but the study delivered zaleplon as an INHALED AEROSOL against an arterial-like peak at 1.9 minutes, while this record models the oral route whose peak is around an hour. At the stored rate the effect site is numerically indistinguishable from plasma, so the parameter does no work here. The record also carries a reference that is a RAT behavioural study with no human content. The deeper limitation is duration rather than coupling: sedation returns to baseline in about four hours against an eight-hour night.
Pharmacokinetics
- Oral — t½ 1.1 h · F 31% · Vd 89 L
Sources: PMID:11192136