. 2016 Jan 1;32(1):32–43. doi: 10.1089/aid.2015.0182

Table 2B.

Steady State Emtricitabine Pharmacokinetic Summary by Analyte and Location

Matrix	Analyte	FTC LLOQ^a	Arm 1	Arm 2	Arm 4	Arm 7
Dose frequency			1 tab 1×/wk	1 tab 2×/wk	2 tabs 2×/wk	1 tab daily
Serum^b	FTC	0.31 ng/ml	0.8 (0.4–0.9)	5.4 (3.7–6.0)	6.7 (5.4–7.6)	70.9 (67.7–81.9)
PBMC total^b	FTC-TP	0.02 pmol/10⁶ cells	0.1 (0.1–0.1)	0.4 (0.2–0.5)	0.6 (0.5–0.6)	2.2 (1.5–2.6)
PBMC CD4⁺ only^b	FTC-TP	0.02 pmol/10⁶ cells	0.1 (0.1–1.7)	0.5 (0.1–6.5)	1.0 (0.3–6.9)	3.2 (0.1–12.3)
Colon homogenate^c	FTC	0.04 ng/mg^d	0.13 (BLQ^e–0.21)	0.49 (0.20–2.08)	1.22 (0.36–5.74)	20.5 (1.87–49.32)
Colon total cells^c	FTC-TP	0.5 fmol/10⁶ cells	BLQ (BLQ–BLQ)	BLQ (BLQ–1.2)	BLQ (BLQ–6.6)	BLQ (BLQ–0.14)
Vagina homogenate^c	FTC	0.08 ng/mg	BLQ, BLQ	BLQ, BLQ, 0.38	BLQ, 0.14	3.02, 3.31
Vagina total cells^c	FTC-TP	0.5 fmol/10⁶ cells	BLQ, BLQ	BLQ, BLQ	BLQ, BLQ	BLQ, BLQ
Rectal fluid^c	FTC	5 ng/sponge	BLQ,BLQ	BLQ	BLQ	20.8
Cervicovaginal fluid^c	FTC	20 ng/ml	124	BLQ, 182	143, 145	2330, 7420
Semen^b	FTC	5 ng/ml	BLQ, 7.4	21, 23	13, 27	907, 992

^{^a}

LLOQ, lower limit of assay quantitation.

^{^b}

Median (range) of individual research participant medians at steady state (day 7–day 35).

^{^c}

Median (range) of day 35 concentrations; when three or fewer values are available, all values are shown without parentheses.

^{^d}

For tissue homogenates, values are reported as “per mg” based on conversion from “per sample” divided by sample weight. LLOQ per mg is based on median of sample weight and LLOQ per sample calculated for each sample.

^{^e}

BLQ, below limit of assay quantitation. (Note: sample mass varies greatly, especially for tissue and tissue cells, with substantial impact of true assay sensitivity.)

FTC, emtricitabine; FTC-TP, emtricitabine triphosphate.