RP-HPLC Method Development and Validation for Simultaneous Estimation of Tadalafil and Silodosin: A Comprehensive Review

Abstract

Benign Prostatic Hyperplasia (BPH) is a prevalent condition in aging men, often managed with pharmacological interventions. The fixed-dose combination of Silodosin, an alpha-1 adrenergic receptor antagonist, and Tadalafil, a PDE5 inhibitor, has gained regulatory approval for BPH management. This review highlights the principles of RP-HPLC method development and validation for simultaneous estimation of these drugs in pharmaceutical dosage forms. It emphasizes chromatographic optimization, stability-indicating approaches, and adherence to ICH guidelines, ensuring accuracy, precision, and robustness.

Introduction

Benign Prostatic Hyperplasia (BPH) is a non-cancerous enlargement of the prostate that causes urinary symptoms. A fixed-dose combination of Silodosin and Tadalafil is used to manage both urinary issues and erectile dysfunction. To ensure the quality, safety, and regulatory compliance of this combination therapy, the development of a reliable analytical method is essential.

RP-HPLC is the preferred technique for simultaneous drug estimation because of its accuracy, resolution, and reproducibility. Method development requires optimizing parameters such as mobile phase, column, flow rate, and detection wavelength. Stability-indicating methods include forced degradation under acidic, alkaline, oxidative, photolytic, and thermal conditions to confirm specificity.

Drug Profiles:

• Silodosin: Alpha-1A blocker that relaxes prostate and bladder neck muscles to improve urine flow.

• Tadalafil: PDE5 inhibitor that increases cGMP levels, aiding both urinary function and erectile performance.

Literature Review: Many analytical techniques exist for individual drugs, but few studies focus on simultaneous, stability-indicating RP-HPLC analysis for the combination—indicating the need for improved methods.

Regulatory Perspective: The CDSCO approved the Silodosin–Tadalafil combination for Phase III trials in 2024. According to ICH Q2(R1) guidelines, methods must be validated for specificity, linearity, accuracy, precision, LOD/LOQ, and robustness.

Conclusion

Developing a validated RP-HPLC method for simultaneous estimation of Silodosin and Tadalafil ensures reliable quality control and supports regulatory submissions. Future research may focus on applying Quality by Design (QbD) principles and exploring green analytical chemistry approaches for method optimization.

References

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Copyright

Copyright © 2025 Sulabh Parmar, Sahil Prajapati, Himanshu Suthar. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.