AssayIndex
Cross-section

MK-677 (Ibutamoren mesylate) impurity profile

Every named species the index has reported alongside MK-677 (Ibutamoren mesylate), how often, at what level, and what its presence implies about the synthesis or the handling. Reporting threshold is 0.05 % area; anything below it is invisible to this page and is silently added to the main peak.

152 recordsmedian 99.37 %spec 98.5 %
Median total impurities 0.64% n=152
Median largest single 0.36% n=152
Worst single observed 1.30% n=152
Named species observed 5 / 5 n=5
Named speciesΔRT (min)Δ mass (Da)Seen inMedian % areaMax % area
free base (des-mesylate, −96 Da)+0.04-96.01188%0.101.26
sulfonamide hydrolysis product (+18 Da)-0.86+18.01183%0.171.30
spiroindane regioisomer+0.44mass-identical82%0.101.28
residual DMF (process solvent)-8.20-551.00079%0.080.44
O-desmethyl metabolite analogue (−14 Da)-0.52-14.01678%0.071.30

free base (des-mesylate, −96 Da)

Retention offset from the main peak
+0.04 min on RG-2
Mass difference
-96.011 Da
Reported in
134 of 152 records (88 %)
Level when reported
median 0.10 %, max 1.26 %
Resolution requirement
Close-eluting — resolution below 1.2 is common and the peaks merge on short gradients.

sulfonamide hydrolysis product (+18 Da)

Retention offset from the main peak
-0.86 min on RG-2
Mass difference
+18.011 Da
Reported in
126 of 152 records (83 %)
Level when reported
median 0.17 %, max 1.30 %
Resolution requirement
Baseline-resolved on the reference method.

spiroindane regioisomer

Retention offset from the main peak
+0.44 min on RG-2
Mass difference
mass-identical — chromatography only
Reported in
125 of 152 records (82 %)
Level when reported
median 0.10 %, max 1.28 %
Resolution requirement
A gradient long enough to separate it. No mass spectrometer will.

residual DMF (process solvent)

Retention offset from the main peak
-8.20 min on RG-2
Mass difference
-551.000 Da
Reported in
120 of 152 records (79 %)
Level when reported
median 0.08 %, max 0.44 %
Resolution requirement
Baseline-resolved on the reference method.

O-desmethyl metabolite analogue (−14 Da)

Retention offset from the main peak
-0.52 min on RG-2
Mass difference
-14.016 Da
Reported in
118 of 152 records (78 %)
Level when reported
median 0.07 %, max 1.30 %
Resolution requirement
Baseline-resolved on the reference method.

Degradation pathways

Degradants are a handling finding rather than a synthesis finding. A lot that shipped clean and arrived oxidised tells you about the courier, not the chemist.

  • sulfonamide hydrolysis under strongly basic conditions
  • no oxidative or proteolytic liability