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.

Ocella Analysis Chromatogram
Ocella Analysis Chemical Structures
1. Ethinyl estradiol
2. Drospirenone
3. Impurity

Method Conditions
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