Forced degradation kinetics of levonorgestrel-based emergency contraceptives on the Ghanaian market using a new developed and validated HPLC-UV method

Emergency contraception (EC) is a key component of reproductive health due to their role in the prevention of unwanted pregnancy. Among the agents used for EC, the levonorgestrel-based emergency contraceptives (LNG-ECs) are popular due to their ease of access and administration. When stored improperly, LNG-ECs break down, leading to treatment failure with attendant unexpected pregnancies. In the current study, the quality and stability of LNG-ECs available on the Ghanaian market were investigated. Ten brands were purchased from Accra, Kumasi, and Takoradi. The levonorgestrel (LNG) content was determined using a newly developed HPLC-UV method, which was validated following the ICH Q2(R2) guidelines. The method demonstrated good linearity (R2 > 0.999), precision (RSD < 2%), accuracy (% recovery: 100.26%-101.2%) and robustness. The analyte solution also remained stable beyond 24 h post-preparation. LNG contents ranged between 96.53% and 103.24%. The samples were subjected to a 14-day forced degradation studies at 50 °C ± 2°C and 75% ± 5% relative humidity. The degradation data were explored using principal component analysis (PCA) and fitted to the following kinetic models: zero-order, first-order, second-order, and second-order polynomial models. The second-order polynomial model provided the best fits for the degradation data. This meant that the brands generally followed a non-linear degradation trend with some brand variations, possibly due to formulation or composition differences. The findings, therefore, demonstrate stability variations in the LNG-ECs brands investigated, even though baseline LNG contents were acceptable. For this reason, manufacturers must optimize their product formulae and manufacturing processes to ensure product stability and efficacy.