Preparation and Evaluation of Intravaginal Ring Containing Drospirenone

Table 1

HPLC conditions.

Column	Diamonsil C18 (250 mm × 4.6 mm, 5 μm)
Column temperature	Ambient temperature
Mobile phase	Water: acetonitrile (gradient elution process, see Table 2)
Flow rate	1.5 mL/min
Injection volume	10 𝜇L
Detection	245 nm
Apparatus	Waters 2695
Runtime	80 min
Retention time	About 32 min