Novel reversed-phase HPLC method for simultaneous determination of ethynodiol diacetate (EDA)/ethinyl estradiol (EE) in pharmaceutical dosage form

Continuous wavelet transform and integration of discrete wavelet transform with principal component analysis and fuzzy inference system for the simultaneous determination of ethinyl estradiol and drospirenone in combined oral contraceptives

In this study, the spectrophotometric method integrated with continuous wavelet transform (CWT) and coupled discrete wavelet transform (DWT) with fuzzy inference system (FIS) was developed for the simultaneous determination of ethinyl estradiol (EE) and drospirenone (DP) in combined oral contraceptives (COCs). The CWT approach was performed in the linearity range of 0.6-6 µg/mL for EE and 0.9 to 18 µg/mL for DP. Biorthogonal with an order of 1.3 (bior1.3) at a wavelength of 216 nm and Daubechies with an order of 2 (db2) at a wavelength of 278 nm were selected as the best wavelet families for obtaining the best zero crossing point for EE and DP, respectively. The limit of detection (LOD) of 0.7677 and 0.3222 µg/mL and the limit of quantification (LOQ) of 2.326 and 0.9765 µg/mL were obtained for EE and DP, respectively. The mean recovery of 103.24% and 99.77%, as well as root mean square error (RMSE) of 0.1896 and 0.1969, were found for EE and DP, respectively. In the DWT, the absorption of the mixtures was decomposed using different wavelets named db4, db2, Symlet2 (sym2), and bior1.3. Each of the wavelet outputs was dimension reduced by the principal component analysis (PCA) method and considered as FIS input. The wavelet of db4 with the coefficient of determination (R2) of 0.9979, RMSE of 0.0968, and mean recovery of 100.63% was chosen as the best one for the EE, while bior1.3 with R2 of 0.9955, RMSE of 0.4055, and mean recovery of 101.93% was selected for DP. These methods were successfully used to analyze the EE and DP simultaneously in tablet pharmaceutical formulation without any separation step. The suggested methods were compared with a reference method (HPLC) using analysis of variance (ANOVA) at a 95% confidence level, and no significant difference was observed in terms of accuracy. The suggested chemometric methods are reliable, rapid, and inexpensive, and can be used as an environmentally friendly alternative to HPLC for the simultaneous estimation of the mentioned drugs in commercial pharmaceutical products.

Quantification of Drospirenone- and Ethinyl Estradiol-Related Impurities in a Combined Pharmaceutical Dosage Form by a Chromatography Method With a QbD Robustness Study

BACKGROUND

The estimation of drugs containing drospirenone (DRSP) and ethinyl estradiol (EE), and their related impurities, in low-dose oral contraceptive drug products is an extremely challenging target. The proposed research sought to develop and validate a stability-indicating method for quantifying drug substances and their related impurities in tablet formulation.

OBJECTIVE

To develop and validate a simple, specific, accurate, precise, and stability-indicating reverse-phase (RP)-HPLC method for quantification of DRSP, EE, and their impurities in accordance with International Conference on Harmonisation (ICH) guidelines.

METHOD

The separation was achieved using an Agilent Zorbax SB C18 column (4.6 mm × 250 mm, 5 µm) with a detection wavelength of 215 nm and mobile phases A (100% acetonitrile) and B (acetonitrile-water, 1 + 3, v/v) at a flow rate of 1.3 mL/min and a column temperature of 40°C.

RESULTS

The recovery study of each impurity was conducted in the range of 24 to 72 µg/mL for DRSP-related impurities and 0.2 to 0.6 µg/mL for EE-related impurities with respect to the specification limit. A linearity study was conducted over a range of 1.5 to 90 µg/mL for DRSP and DRSP-related impurities, and 0.125 to 0.75 µg/mL for EE-related impurities. A Quality by Design (QbD) study demonstrated the method's robustness.

CONCLUSIONS

As per current guidelines, a stability-indicating method has been developed for the determination of impurities in DRSP/EE film-coated tablets. A QbD-based robustness test was performed and the method was found to be robust.

HIGHLIGHTS

An accurate, precise, stability-indicating, gradient RP-HPLC method has been developed and validated to determine DRSP, EE, and nine related impurities in tablet formulation. A QbD technique was used to establish a robustness study.