*Hussien O. Kadi1 and Alaa AL-Maktari2
1Faculty Medical Sciences, Yemen University, Sana’a, Yemen
2Faculty Medical Sciences, Yemen University, Sana’a, Yemen
*Corresponding: Prof. Dr. Hussien O. Kadi, Faculty Medical Sciences, Yemen University, Sana’a, Yemen. E-mail: hussien62@yahoo.com
Abstract
Introduction:
Sildenafil is a selective phosphodiesterase type 5 (PDE5) inhibitor widely used for the treatment of erectile dysfunction and other related disorders. Oral gel formulations are gaining interest due to improved patient compliance, faster onset of action, and ease of administration. Stability testing is a critical component of pharmaceutical development, ensuring that formulations maintain their quality, safety, and efficacy throughout their intended shelf life. This study was designed to evaluate the accelerated and predictive long-term stability of Sildeflexe, a sildenafil 12.5mg Yemeni honey-based oral gel sachet.
Methods: The stability of Sildeflexe, a novel oral gel sachet formulation containing sildenafil citrate (12.5 mg per 5 g Yemeni honey base), was evaluated under accelerated and predicted long-term conditions according to ICH Q1A(R2) guidelines. Physical appearance, pH, drug assay, viscosity, and microbial safety were assessed over a six-month period at 40 °C ± 2 °C / 75% RH ± 5%.
Results: Demonstrated that Sildeflexe maintained acceptable pharmaceutical quality, with no significant changes in appearance, drug assay (>95% retention), or microbial contamination. Yemeni honey proved to be an effective natural excipient for stability, offering viscosity and antimicrobial properties.
Conclusion: The oral sildenafil gel demonstrated excellent stability across all tested parameters over a six-month period. These findings provide a strong basis for further clinical development and market readiness of the product.
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