A Novel Paclitaxel Microemulsion Containing a Reduced Amount of Cremophor EL: Pharmacokinetics, Biodistribution, and In Vivo Antitumor Efficacy and Safety

Table 2

The main pharmacokinetic parameters of PTX after intravenous administration of the PTX injection or microemulsion at 5 mg/kg PTX in SD rats (mean ± S.D., 𝑛=5).

Parameter	Units	PTX microemulsion	PTX injection
A	ng/mL	9245.8±3232.7	9315.2±2601.7
B	ng/mL	1694.0±530.4	1611.0±651.5
𝛼	1/h	5.934±2.40	6.219±1.104
𝛽	1/h	0.689±0.216	0.837±0.139
𝑡1/2𝛼	h	0.134±0.057	0.114±0.019
𝑡1/2𝛽	h	1.074±0.279	0.846±0.130
t 1/2	h	0.283±0.098	0.278±0.064
K 12	1/h	2.393±1.197	2.431±0.537
K 21	1/h	1.556±0.777	2.035±0.421
K 10	1/h	2.674±0.826	2.590±0.523
AUC0–∞	h ng/mL	4141.7±787.6	4671.1±981.6
Vc	mL/kg	1242.0±385.4	969.7±234.1
CL	mL/h/kg	1239.2±212.4	1120.1±298.1

A and B: the hybrid parameters; 𝛼: distribution constant; 𝛽: elimination constant; 𝑡_1/2𝛼: half-time of phase I; 𝑡_1/2𝛽: half-time of phase II; K ₂₁: rate constant for drug leaving compartment 2 and passing into 1; K ₁₂: rate constant for drug leaving compartment 1 and passing into 2; K ₁₀: elimination constant from the central compartment; AUC_0–∞: area under the curve; Vc: apparent volume of distribution of the central compartment; CL: clearance from the two-compartment model.