Development and validation of a fluconazole quantification method for the stability study of an investigational medical product

Context
Capsules of fluconazole 50 mg and their placebo were requested to our hospital pharmacy for a clinical trial.

Objectif
The main goal of this study is to develop and to validate a stability indicating quantification method for fluconazole using High-Performance Liquid Chromatography and Ultra-Violet detection (HPLC-UV). This method is meant for stability assessment and post-production controls of the capsules.

Materials and methods
The calibration standard range is situated between 100 and 500 µg/mL. The validation standard range is situated between 150 and 450 µg/mL The HPLC system consists in a C18 stationary phase (150 x 4.6 mm, 5 µm) set at 40°C and a methanol / acetate buffer pH 5.0 (40:60, v/v) mobile phase. The detection wavelength used is 261 nm. The accuracy profile, used as a validation tool following SFSTP recommendations enables to estimate (i) linearity, (ii) specificity and selectivity, (iii) accuracy, (iv) quantification limits and (v) measurement bias based on the validation standards concentrations. A forced degradation study (FDS) [3] is performed on the capsules content using (i) alkaline (1 M NaOH, 80°C, 4 h), (ii) acidic (1 M HCl, 80°C, 4 h), (iii) oxidative (H2O2 3%, 3:1, 80°C, 4 h), (iv) heat (80°C, 4h) and (v) photo-oxidative (UV 265 nm, 3h) condition to identify potential degradation products.

Results
No interferences are observed between the signals of the active pharmaceutical ingredient, the excipients and the degradation products (chromatographic resolution ≥ 1.5). Fluconazole retention time is 3.1 min. All the validation parameters are compliant with the following specifications: specificity and selectivity, linearity (R² > 0.99), precision (intra and inter day Coefficient of Variation (CV) < 5% and 8% respectively) and accuracy (CV < 10%). The tolerance range limit is within the acceptability range limit (10%). The FDS in alkaline condition reveals degradation products with retention times at 1.27, 1.44, 1.61 and 1.89 min. All these degradation products seem to be due to the excipient’s degradation. No other degradation products can be identified during the other FDS conditions.

Discussion / Conclusion
This fluconazole stability indicating quantification method based on the use of HPLC-UV is validated, allowing to perform the stability study of the fluconazole capsules in the context of a clinical trial.

References
[3] Coord. V. Sautou. 1ère éd. SFPC/GERPAC, 2013. Guide méthodologique des études de stabilité des préparations.

See the poster