Reversed-phase liquid chromatographic method for estrogen determination in equine biological samples

Area of Science:

• Endocrinology and Reproductive Biology
• Analytical Chemistry
• Pharmacology

Background:

• Equine unsaturated estrogens are key components in hormonal replacement therapy for women.
• These vital hormones are synthesized by the fetoplacental unit during equine gestation.

Purpose of the Study:

• To develop and validate a quantitative method for determining specific equine estrogens in pregnant mare plasma.
• To establish baseline hormonal levels throughout equine pregnancy.

Main Methods:

• Weekly blood sampling from pregnant mares via jugular venipuncture with EDTA anticoagulant.
• Plasma analysis involving enzymatic hydrolysis, liquid-liquid extraction, and HPLC with UV detection.
• Utilized an ODS Hypersil column for precise separation and quantification.

Main Results:

• The developed method demonstrated high precision, specificity, and accuracy.
• Hormonal levels varied throughout pregnancy, with peak concentrations observed at different weeks for E1, EL, EQ, and 17dEQ.
• Quantified ranges for E1, EL, EQ, and 17dEQ were 97.91-449.13, 116.47-266.02, 74.92-235.54, and 84.26-300.03 ng/mL, respectively.

Conclusions:

• A reliable method for quantifying equine estrogens in pregnant mare plasma was successfully established.
• This method is applicable for studying estrogen bioavailability and bioequivalence in pharmaceutical formulations.