Oral suspension of spironolactone: development and validation of an analytical method by HPLC-UV

Introduction
Our pediatric cardiology unit treats children with heart failure by a spironolactone suspension (5mg/mL). Its important demand suggests to make it a hospital preparation: improved accessibility, securing of the preparation by quality controls. The implementation of a validated analytical method is necessary in order to evaluate the active substance content (one of the controls allowing the release of the batch). High performance liquid chromatography coupled with an ultraviolet detector (HPLC-UV), a separative and quantitative technique, was chosen to perform this assay.

Material and method
The parameters of the HPLC-UV are as follows: an injection volume of 20 μL, a pump flow rate set at 1.0 mL/min, a mobile phase composed of water for injection and acetonitrile (30; 70 v/v), a C18 Luna^® column (3 µm, 150 mm x 4.60 mm) thermostated at 40°C with an octadecylsilylated stationary phase, and a detection at 254 nm. The calibration standards are 15, 50 and 75µg/mL and the validation standards are 35, 50 and 65µg/mL. Using the methodological guidelines for stability studies of hospital pharmaceutical preparations 1, we evaluated the statistical parameters of the method (specificity, linearity, precision, accuracy).

Results
There was no matrix effect with a reproducible spironolactone retention time: 2.18min±5% (specificity), the mean response function Y= 3.49x10-2 (±1.126x10-3)X -0.197(±0.232) is a straight line with mean R2 = 0.999(±2.6x10-4) >0. 95 and model residuals within the ±0.05 interval (linearity), a mean intra-day coefficient of variation (CV) <5% (repeatability) and a mean inter-day CV <8% (reproducibility) justifying reliability, with a satisfactory accuracy profile (recoveries belong to the interval [90%;110%]).

Discussion and conclusion
The quantified statistical parameters are all within specifications. This analytical method will therefore allow the determination of the spironolactone content of these drinkable suspensions on a routine basis. This control supports the quality and safety of the release of a batch of hospital preparations.

1 : https://www.gerpac.eu/IMG/pdf/guide_stabilite_anglais.pdf

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