Table 3.

Encapsulation of paclitaxel (PTX) in various microemulsion formulations at 37 °C. Each formulation contains 2 wt % surfactant, 1 wt % glycerol, and different amounts of tributyrin or ethyl caproate.

(a) Mixed Surfactant Systems Consisting of PANNOX 74 and Tween 80
Mixed Surfactant (w/w) $\left(\frac{Pannox74}{Pannox74+Tween80}\right)$	Oil Content	Estimated PTX (ppm)	Measured PTX (ppm)	Solubilization Efficiency (%)
0.2	0.3 wt % Tributyrin	79.8	52	65.2
0.4	0.3 wt % Tributyrin	79.8	61	76.5
0.5	0.3 wt % Tributyrin	79.8	71.2	89.2
0.6	0.3 wt % Tributyrin	79.8	57.3	71.8
0.8	0.3 wt % Tributyrin	79.8	53.5	67.1
0.2	0.7 wt % Ethyl Caproate	101.7	60.4	59.4
0.4	0.7 wt % Ethyl Caproate	101.7	76.8	75.5
0.5	0.7 wt % Ethyl Caproate	101.7	91.2	89.7
0.6	0.7 wt % Ethyl Caproate	101.7	73.8	72.6
(b) Mixed Surfactant Systems Consisting of Pannox 74 and Cremophor EL
Mixed Surfactant (w/w) $\left(\frac{Pannox74}{Pannox74+Cremophor\mathrm{EL}}\right)$	Oil Content	Estimated PTX (ppm)	Measured PTX (ppm)	Solubilization Efficiency (%)
0.5	0.3 wt % Tributyrin	79.8	60.5	75.8
0.5	0.4 wt % Tributyrin	106.4	91.8	86.3
0.4	0.5 wt % Tributyrin	133.0	70.9	53.3
0.5	0.5 wt % Tributyrin	133.0	88.7	66.7
0.6	0.5 wt % Tributyrin	133.0	66.9	50.3
0.2	0.7 wt % Ethyl Caproate	101.7	63.9	62.8
0.4	0.7 wt % Ethyl Caproate	101.7	72.9	71.7
0.5	0.7 wt % Ethyl Caproate	101.7	82.8	81.4
0.4	0.9 wt % Ethyl Caproate	130.8	76.7	58.6