Table 3.

Mean residual concentration (μg/mL), mean residual concentration (%), color changes, initial pH and post-study pH of 10 mg/mL and 50 μg/mL apomorphine HCl solutions (purged with nitrogen) after 168 hours

Experimental conditions	Experimental temperature (°C)	Mean residual concentration (%) at 168 hours*	Mean residual concentration at 168 hours	Color of solution at 168 hours	Initial pH	pH at 168 hours
Apomorphine HCl (10 mg/mL) in 0.1% SMB (buffered by acetate buffer)	25	102.2	10.2 mg/mL	Colorless	4.00	3.81
Apomorphine HCl (10 mg/mL) in 0.1% SMB (no buffer)	25	100.0	10 mg/mL	Colorless	2.71	2.27
Apomorphine HCl (50 μg/mL) in 0.1% SMB (buffered by acetate buffer)	25	20.8	10.4 μg/mL	Colorless	4.00	3.88
Apomorphine HCl (50 μg/mL) in 0.1% SMB (no buffer)	25	41.8	20.9 μg/mL	Colorless	3.44	3.04

Notes: Apomorphine HCl sample solutions for each assay were prepared in duplicate (n=2).

^*The acceptable limit of mean residual concentration at the end of period of stability study is between 95% and 105%.

Abbreviation: SMB, sodium metabisulfite.