SPDS Set 1 ERP Book

PDE5-004

Question

Answer

General

AOAC Method Number:

PDE5-004

Testing for Phosphodiesterase Type 5 (PDE5) Inhibitors in Dietary Supplements

Method Title:

Method Author(s): Reviewer Name:

Jerry Zweigenbaum

This method utilizes a luminescence quenching to measure presence and semi-quantitation of PDE5 inhibitor. It requires PDE5 enzyme reaction with cyclic guanosine monophoshate deactivating PKA which maintains level of ATP for luminscent reaction. Inhibition of enzyme allows active PKA to react with ATP and thus reduces luminescence. This method identifies the presence of PDE5 inhibitor and provides a semi-quantitative measurement. The measurement is of activity and not identification nor concentration of the molecule responsible for inhibition. This would be applicable to screening dietary supplements for PDE5 inhibitors. The method appears to be an excellent screening tool and provides a quantitative indication of activity. There is no discussion of possible false positive and negative results. The diagram describing the reactions involved needs a key as it is difficult to follow. The procedure to perform the test seems straightforward and clear. This method appears capable of detecting and measuring activity of PDE5 inhibitors that have been altered to escape molecular detection (designer drugs). There is no way to identify the specific molecule producing inhibition. False positives seem more likely than false negatives which makes it a potentially excellent screening method but a confirmatory method

Summary of Method

Method Scope / Applicability:

General Comments About the Method:

Method Clarity

Pros/Strengths

Cons/Weaknesses