Sildenafil Testing in Foods: Detecting Undeclared PDE-5 Inhibitors with QuEChERS

Undeclared pharmacologically active substances are an increasing concern for manufacturers, importers, and distributors of food supplements. Products marketed as natural or performance-enhancing may contain undeclared pharmaceutical ingredients such as Sildenafil or Tadalafil.

Regulatory authorities regularly report cases in which products marketed as foods or food supplements contain undeclared PDE-5 inhibitors. Since these substances cannot be detected by sight, smell, or taste, reliable analytical testing is essential to ensure product safety and compliance with regulatory requirements.

Why Sildenafil and Tadalafil Are Analytically Relevant

Sildenafil and Tadalafil belong to the class of phosphodiesterase type 5 (PDE-5) inhibitors and are prescription-only medicines used to treat erectile dysfunction. Both compounds are chemically stable and can be incorporated into high-fat or high-sugar food matrices, such as chocolate or honey, without affecting the product's appearance or sensory properties.

As a result, their presence cannot be identified visually or organoleptically. Reliable detection is only possible through targeted instrumental analysis.

For manufacturers, importers, and retailers, this means that without appropriate analytical testing, the presence of these pharmaceutical substances in imported raw materials or finished products cannot be ruled out.

Challenges in Detecting PDE-5 Inhibitors in Complex Food Matrices

Chocolate, honey, and herbal paste matrices present significant analytical challenges. Their high fat or sugar content, complex matrix components, and often highly variable compositions make efficient extraction difficult.

In addition, PDE-5 inhibitors may be present at relatively low concentrations that are nevertheless pharmacologically active. A reliable screening method must therefore combine high sensitivity with excellent selectivity to detect these compounds accurately in complex food matrices.

QuEChERS Method for Food Analysis

For the analysis of food supplements and complex food matrices, QuEChERS extraction has become a well-established sample preparation technique. The method enables efficient and reliable extraction from a wide range of products and provides high-quality extracts for subsequent LC-MS/MS analysis.

Detection of Sildenafil and Tadalafil by LC-MS/MS

The identification and quantification of Sildenafil, Tadalafil, and other PDE-5 inhibitors are performed using highly sensitive liquid chromatography–tandem mass spectrometry (LC-MS/MS).

Combined with appropriate sample preparation, this analytical approach enables selective and reliable detection even in challenging matrices such as chocolate, honey, and herbal pastes.

Why This Matters for Manufacturers and Importers

Risk-based quality control is essential for manufacturers, importers, and distributors of foods and food supplements. Products sourced through international supply chains or containing complex botanical ingredients may present an increased risk of undeclared pharmaceutical adulteration.

Targeted screening for PDE-5 inhibitors helps companies identify undeclared pharmacologically active substances at an early stage, comply with regulatory requirements, ensure product safety, and reduce risks throughout the supply chain.