Lisdexamfetamine

Oral:

Tmax 1 hour
Half-life 0.47 hours
https://pubmed.ncbi.nlm.nih.gov/18991468/
Absorption half-life 1.08 hours
Bioavailability: 96.4%
Dextroamphetamine tmax after LDX: 4.2 hours (2.5 hours for I.V.) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3666194/
Dextroamphetamine tmax after LDX (adults): 3.8 hours (4.7 hours after high-fat meal)
Dextroamphetamine tmax after LDX (ages 6-12 years): 3.5 hours
https://www.accessdata.fda.gov/drugsatfda_docs/label/2007/021977lbl.pdf

41.5% is converted to amphetamines

Conversion from lisdexamfetamine dimesylate (Vyvanse) to d-amph base is 0.29677
vyvanse chemical formula = C₂₅H₂₅N₃ + (CH₄O₃S)₂
molar mass of vyvanse is 263.385 g/mol, adding (CH₄O₃S)₂ would make a total of 455.605 g/mol
dextroamphetamine molar mass = 135.2062
CH₄O₃S molar mass = 96.11 g/mol
vyvanse to dextroamphetamine freebase = 135.2062 / (263.385 g/mol + 96.11*2) = 0.29677 = 29.68%
Dextroamphetamine equivalent dose = 0.29677 * (bioavailability=0.964) = 0.286 = 28.6%