Comparison of Heavy Labeled (SIL) Peptide versus SILAC Protein Internal Standards for LC-MS/MS Quantification of Hepatic Drug Transporters

Table 3

Bench-top and freeze-thaw stability of OATP1B1, OATP1B3, OATP2B1, and P-gp.

Transporter (peptide)	Human liver	Freeze-thaw stability	Bench top stability
OATP1B1 (NVTGFFQSFK)	HL1	116.5±0.8	90.5±0.8
	HL2	102.9±3.9	99.3±8.2
	HL3	99.3±11.6	94.3±5.7
OATP1B3 (NVTGFFQSLK)	HL1	98.8±6.9	93.8±10.5
	HL2	109.2±2.9	94.7±5.1
	HL3	93.9±10.7	96.0±4.4
OATP2B1 (VLAVTDSPAR)	HL1	93.9±4.6	91.8±20.0
	HL2	95.7±18.2	97.8±10.9
	HL3	94.4±4.6	91.6±5.1
P-gp (NTTGALTTR)	HL1	95.3±2.2	85.4±6.7
	HL2	102.5±4.6	95.9±6.0
	HL3	99.6±11.9	105.5±12.8