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PDE5-003
analogs, nor does it include avanafil, lodenafil carbonate,
mirodenafil, udenafil as specified in SMPR 2014.012 for
PDE5 screening method.
Agilent 1200 is a 400 bar/6000 psi HPLC system, typically
using 0.007" ID tubing & capillary needle seat in flow
path from injector to column, and column to detector.
Authors refer to this as UHPLC system; is it possible their
UHPLC system is an Agilent 1260 or 1200SL (600
bar/9000 psi) system? Were any modifications made to
minimize extra column volume?
Supporting Data
General Comments
the power of MS/MS technique highlighted by ability to
distinguish Gendenafil (same M+H as Yohimbine) based
on examination of M+H product ions for both
compounds.
Authors provide sources for standards - again from 2012,
so this needs to be updated to current to reflect
additional known PDE5 inhibitors.
I also believe that MS/MS is going to be needed for a
proper screening method since analogs are closely
related and may not be fully resolved in HPLC/UHPLC to
allow for UV detection.
Method Optimization
not clear how this method was optimized or if further
optimization might be required with inclusion of
additional PDE5 analogs.
Method specifies Zorbax 1.8um SB-C18 50x2.1mm
column and indicates other C18 columns would need to
be evaluated for use in this procedure. Performance
criteria (e.g. efficiency, resolution, retention) for column
not indicated.
Performance Characteristics
Analytical Range:
working standards range of 1–5 μg/mL (1-5 ppm) ; 0.5-5
ug/mL (0.5-5 ppm) in LC/MS method.
LOQ:
Not specified
Accuracy/Recovery
Not specified
Precision (RSDr)
Not specified
Reproducibility (RSDR)
Not specified
System Suitability
Not specified
Safety Review