Tazarotene
Tazarotene, a topical compound. Acetylenic retinoid prodrug — rapidly hydrolysed by esterases in the skin to the active carboxylic-acid… Transdermal half-life 18 h.
Acetylenic retinoid prodrug — rapidly hydrolysed by esterases in the skin to the active carboxylic-acid metabolite tazarotenic acid, which selectively activates RAR-β and RAR-γ. Potent normalisation of keratinocyte differentiation with anti-proliferative activity (basis for the psoriasis indication — reduces T-cell-driven keratinocyte hyperproliferation). Among topical retinoids, tazarotene is the most irritating, which is also why the newer 0.045% lotion vehicle exists. Systemic exposure to tazarotenic acid is <1% of applied dose but still drives a pregnancy-category X labelling.
ANALYTE: TAZAROTENIC ACID, and this record is the BEST-SOURCED of the nine rather than a candidate for stripping, which is what I had wondered about. Its existing citation carries BOTH stored values for the metabolite explicitly: "Tazarotenic acid ... is rapidly eliminated ... with a terminal half-life of about 18 hours" and "The systemic bioavailability of tazarotene (measured as tazarotenic acid) is low, approximately 1%" — that parenthetical names the analyte outright. So a systemic half-life IS meaningful here despite the topical route. One caveat worth carrying: bioavailability rises with use, from 1% single-dose to 5% or less at steady state in psoriasis. mw 351.46 is the parent ester. MASS: the stored molecular weight described the PARENT while pk_analyte declares the metabolite, so the one field that must name a single species named the wrong one. LATENT RATHER THAN LIVE — this record carries no occupancy rows and is no other record interaction perpetrator — but it is one authored edge away from being live, because both consumers of the field (the micromolar-to-mass conversion for a kinetics edge, and the affinity the app renders from a stored occupancy concentration) want the species that actually circulates, which is the species pk[] already describes.
Pharmacokinetics
- Transdermal — t½ 18 h · F 1%
Sources: PMID:10554045