Separation of Drospirenone and Ethinyl Estradiol
Good Selectivity with high Efficiency Peaks can be achieved analyzing Ocella Tablets. This can be helpful since Ethinyl Estradiol is present at a much lower concentration than Drospirenone and therefore can be difficult to detect; the high Efficiency can contribute to a stronger Signal in detection thus increasing Sensitivity. Furthermore, the isocratic Mobile Phase is very simple to prepare or even obtain pre-mixed, allowing for streamlined routine Assays of this formulation in QC laboratories.
Figure A shows the full view of the Chromatogram, with the Drospirenone Peak shown in its entirety. Figure B shows a zoom-in view so that the tiny Ethinyl Estradiol Peak can be seen more clearly and measured. There is even an Impurity Peak observed eluting after Drospirenone.
1. Ethinyl estradiol
Column: Cogent Bidentate C18 2.o™, 2.2μm, 120Å
Catalog No.: 40218-05P-2
Dimensions: 2.1 x 50mm
Mobile Phase: 50:50 DI Water / Acetonitrile (v/v)
Injection vol.: 4.0µL
Flow rate: 0.2mL / minute
Detection: UV @ 265nm
Sample Preparation: Ocella® Tablet (3mg strength Drospirenone and 0.03mg strength Ethinyl Estradiol) was ground and added to a 10mL volumetric flask containing a portion of Acetonitrile. It was sonicated for 10 minutes and diluted to mark. After mixing, a portion was filtered (0.45μm, Nylon Syringe Filter) and used for HPLC injections.
Note: The combination formulation of Drospirenone and Ethinyl Estradiol is used as a contraceptive and also to alleviate symptoms of premenstrual dysphoric disorder.
No 338 Ocella® Tablet Analyzed with HPLC pdf 0.3 Mb Download File