AUC	Area under the drug-time curve
BAEE	N-benzoyl-L-arginine ethyl ester hydrochloride
BBB	Blood–brain barrier
B/P	Blood-to-plasma
cAMP	Cyclic adenosine monophosphate
Cmax	Maximum plasma concentration
CNS	Central nervous system
COPD	Chronic obstructive pulmonary disease
DMSO	Dimethyl sulfoxide
ESI	Electrospray ionization
HQC	High-quality control
HSA	Human serum albumin
IS	Internal standard
ISR	Incurred sample reanalysis
LC-MS/MS	Liquid chromatography-tandem mass spectrometry
LLOQ	Lower limit of quantitation
LQC	Low-quality control
MQC	Medium-quality control
MRM	Multiple reaction monitoring
MRT	Mean residence time
NSB	Non-specific binding
PDE4	Phosphodiesterase 4
QC	Quality control
RE	Relative error
RSD	Relative standard deviation
SD	Standard deviation
S/N	Signal-to-noise ratio
SPF	Specific pathogen-free
t1/2	Elimination half-life
ULOQ	Upper limit of quantification