Table 1. Solubility of Tretinoin in different oils, surfactant and co-surfactant (mean ± SD, n = 3) .

Phase type	Excipient	Solubility (mg/ml)
oil	Oleic acid	3.61± 0.3
	Isopropyl Myristat	1.32 ± 0.091
	Oleic acid + Transcutol P	3.69 ± 0.046
	Isopropy Myristat +Transcutol P	4.85 ±0.09
surfactant	Tween 80	4.27 ± 0.12
	Span 80	2.494 ± 0.03
	labrasol	3.232 ± 0.23
co-surfactant	Propylene glycol	7.93 ± 0.06