Phosphate And Phosphite Content In Minodronic Acid

- Jan 01, 2021-


Minodronic acid is a bisphosphonate osteoporosis treatment drug. It belongs to the third generation of bisphosphonate drugs. Ethyl Trans-4-oxo-2-butenoate CAS 2960-66-9 manufacturers told us that it inhibits the activity of farnesyl pyrophosphate (FPP) synthase in osteoclasts. The bone resorption of bone cells reduces bone turnover and has the effect of preventing and treating osteoporosis. Because phosphate and phosphite are introduced during the synthesis process, these two related substances need to be measured in the finished product. In the Chinese Pharmacopoeia, the determination of phosphate and phosphite in bisphosphonates is separated by KOH gradient elution, which requires an eluent generator, and the cost of the instrument is relatively high. When there is no eluent generator, a mixed mobile phase of sodium carbonate and sodium hydroxide can be used for elution, and phosphate and phosphite can be better separated. Ethyl Fumaraldehydate is the maninly intermediate of Minodronic acid.

Sample pretreatment:

Take 100 mg of the sample, accurately weigh it, place it in a 100 mL volumetric flask, add 10 mL of 0.1 mol/L sodium hydroxide solution, dissolve by ultrasound, add 10 mL of 0.1 mol/L hydrochloric acid to neutralize, and then quantitatively dilute with water to make Scale, shake, and inject.

Test Conditions:

Instrument: ICS 600 system; AS-AP autosampler.

Analyzing column: IonPac AS14, 9 μm, 250×4 mm (P/N: 046124);

Guard column: IonPac AG14, 9 μm, 50×4 mm (P/N: 0 46134);

Eluent: 3.2 mmol/L Na2CO3 + 2 mmol/L NaOH

Flow rate: 1.0 mL/min;

Injection volume: 20 µL;

Detection: suppressed conductance, AERS 500 4 mm (P/N: 082540), self-regeneration mode


When using AS14 anion exchange chromatographic column, when eluting with Na2CO3 and NaHCO3 solutions, the phosphate exists in the form of HPO42- and cannot be separated from the phosphite. It is eluted with Na2CO3 and NaOH solutions. The phosphate exists in the form of PO43-. Phosphate has good resolution and is not interfered by other conventional anions. With suppressed conductivity detection, it can be used for the determination of phosphate and phosphite in minodronic acid.