Raloxifene Identification and Assay by HPLC

Raloxifene Hydrochloride USP Monograph Methods


Raloxifene is an oral selective estrogen receptor modulator (SERM) that has estrogenic actions on bone and anti-estrogenic actions on the uterus and breast.

It is used in the prevention of osteoporosis in postmenopausal women.

Common commercial brand Names:

Raloxifene hydrochloride was developed by Eli Lilly and Company. In 2010, sales in were $1.3 billion globally; the patent expired in 2014.


In this compilation, we have used the USP 37–NF 32 experimental conditions for raloxifene hydrochloride in the following areas:

  • Identification — FTIR
  • Assay — HPLC and UHPLC (isocratic method)
  • Related Substances — HPLC (gradient method)

The assay and related substances have been carried out with HPLC using RP-8 and RP-18 endcapped columns. In addition, the assay method has been scaled to a shorter UHPLC column dimension with a different particle size.

Identification and Assay


Raloxifene hydrochloride contains not less than (NLT) 97.5% and not more than (NMT) 102.0% of raloxifene hydrochloride (C28H27NO4S·HCl), calculated on the dried basis.


A. Infrared absorption
B. Identification Tests—USP General Chapter 191, Chloride: The sample being dissolved in methanol meets the requirements.

ASSAY—HPLC and UHPLC (isocratic method)

Dissolve 7.2 g of monobasic potassium phosphate in 1,000 mL of water. Add 1.5 mL of phosphoric acid, and further adjust with phosphoric acid or potassium hydroxide solution to a pH of 2.5 ± 0.1.

Mobile phase: Acetonitrile and Buffer (33:67)
System suitability solution:
Prepare as directed in the test for Organic Impurities.
Standard solution:
0.05 mg/mL of USP Raloxifene Hydrochloride in Mobile phase

Sample solution: 0.05 mg/mL of raloxifene hydrochloride in Mobile phase

Chromatographic System
See USP General Chapter 621, Chromatography, System Suitability.

Detector: UV 280 nm
Column: 4.6 mm × 15 cm (3.5 µm) base-deactivated packing L7
Column temperature: 35 °C
Flow rate: 1.5 mL/min (Note: We used 1.0 mL/min for the HPLC method and 0.21 mL/min for the UHPLC method.)
Injection volume: 10 µL

System Suitability

System suitability solution

Suitability Requirements

  • Resolution: NLT 2.0 between raloxifene and raloxifene related compound C
  • Tailing factor: NMT 2.0 for raloxifene
  • Relative standard deviation: NMT 0.7% for raloxifene


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