Table 1.
Release of MTX and MTX-α peptides from DK226
Treatment | pH | Released concentration (ng/mL) MTX MTX-α-Phe MTX-α-Phe-Phe |
% of released MTX | % peak area of MTX-α-Phe after 24-h incubation | ||
---|---|---|---|---|---|---|
Synovial tissue homogenate | 4.0 | 8.82 | BLQb | BLQc | 1.2 | 0e |
7.4 | BLQa | BLQb | BLQc | 0 | 100 | |
Synovial fluid | 4.0 | 1.14 | 2.02 (1.53)d | 1.29 (0.783)d | 0.5 | 80.1 |
7.4 | BLQa | BLQa | BLQa | 0 | 100 |
DK226 was incubated in rabbit synovial tissue homogenate or synovial fluid at pH 4.0 or pH 7.4 for 24 h at 37 °C. Release of MTX and MTX-α peptides was measured by LC/Q-TOF-MS. MTX-α-Phe was used as a reference compound to assess the metabolic stability, and the percent peak area of intact MTX-α-Phe and MTX released from MTX-α-Phe were monitored by LC-UV
MTX methotrexate, Phe phenylalanine, BLQ below lower limit of quantification
aBLQ (below LLOQ); <1 ng/mL
bBLQ; <5 ng/mL
cBLQ; <10 ng/mL
dMTX-equivalent concentration
ePercent peak area of MTX-α-Phe after 3-h incubation