Analysis of Alprostadil by HPLC with Post-Column Derivatization

Alprostadil (Prostaglandin E1) is a drug that has vasodilation properties and is used to treat erectile dysfunction and other medical conditions. This medication is available in injectable form and in suppository form. Since Prostaglandin E1 has low UV absorbance, the analysis of the formulations could be difficult. The addition of post-column derivatization increases the sensitivity and specificity of the analysis.

Analytical Conditions

Analytical column: Reversed-phase C18 column (150 × 4.6 mm)

Temperature: 37 °C

Flow rate: 1 mL/min

Mobile phase: 30% Acetonitrile – 70% of 0.02 M Potassium Phosphate monobasic (adjusted to pH 3)

Or Alternative Conditions

Mobile phase: 25% Acetonitrile – 75% of 0.0067 M Potassium Phosphate buffer pH 6.3

Injection volume: 20 µL

Figure 1: Calibration curve for Alprostadil.

Post-Column Conditions

Post-column system: Pinnacle PCX

Reactor volume: 2 mL

Reactor temperature: 60 °C

Reagent: 1 mol/L Potassium Hydroxide

Reagent flow rate: 1 mL/min

Detection: UV 278 nm

Figure 2: Calibration curve for β-Naphthol.

Calibration

Alprostadil: 0.1 µg/mL – 10 µg/mL

β-Naphthol (Internal Standard) 0.25 µg/mL – 10 µg/mL

Figure 3: Chromatogram of Alprostadil and β-Naphthol (internal standard).

Make stock solutions of Alprostadil and β-Naphthol in anhydrous Ethanol. Prepare working standards by appropriate dilution of stock solution with mobile phase.

Pickering Laboratories, Inc.

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tel. (800) 654-3330, (650) 694-6700

Website: www.pickeringlabs.com