Table 3.

Intrinsic Photostability Performed in Hydroethanolic Solution

Vial Type	Concentration	Time	Aerobic Contact	Remaining (%)	Loss (%)
Glass vial irradiation	0.5%	24 h	Limited aerobic contact	98	2
			Full aerobic contact	98	2
Quartz cuvette irradiation	0.5%	24 h	Limited aerobic contact	99	1
			Full aerobic contact	98	2

Abbreviations: IR, infrared; MCE, Methoxypropylamino Cyclohexenylidene Ethoxyethylcyanoacetate.

MCE was solubilized in 0.5 g/100 ml water/ethanol 50/50 (v/v), and the different vials were placed in an open glass plate ready for the irradiation step. Solar simulation was performed using a Suntest CPS apparatus (Atlas Material Testing Technology, Mount Prospect, IL) with a xenon arc lamp equipped with a filter cutting <295 nm and in accordance with solar spectral distribution excepting IR (in order not to overheat samples). Duration of the test was 24 hours at room temperature. Vials containing MCE were full (limited aerobic contact) or half (full aerobic contact) filled. Aliquoting and analytical follow-up were performed using a UPLC/DAD Acquity apparatus (Waters, Milford, MA). MCE was intrinsically photostable after exposure to solar simulation. Indeed, MCE did not lose its ability to filter light, especially solar light, and UVA wavelengths over time when exposed to solar simulation in solution. This ability was not compromised in the presence of more oxygen.