Maytansinoid DM 1

Mertansine (DM1) is a microtubulin inhibitor which binds at the tips of microtubules and suppresses the dynamicity of microtubules.. Mertansine is an antibody-conjugatable maytansinoid that was developed to overcome systemic toxicity associated with maytansine and to enhance tumor-specific delivery.

Mertansine is an organic heterotetracyclic compound and 19-membered macrocyclic lactam that is maytansine in which one of the hydrogens of the terminal N-acetyl group is replaced by a sulfanylmethyl group. It has a role as an antineoplastic agent and a tubulin modulator. It is an alpha-amino acid ester, a carbamate ester, an epoxide, an organic heterotetracyclic compound, an organochlorine compound, a thiol and a maytansinoid. It derives from a maytansine.|An ansa macrolide isolated from the MAYTENUS genus of East African shrubs.

Maytansinoid conjugation method C: [00352] A vial was charged with 125 (12.6 mg, 0.00876 mmol). Trifluoroacetic acid (1 mL) was added, and the reaction stirred at room temperature for 5 min. LCMS showed complete deprotection after 5 min. LCMS M/Z = 669.9 [(M + 2) / 2]. All solvent was removed in vacuo, and to the remaining residue was added a solution of DM1 (11.8 mg, 0.0160 mmol) in DMF (5 mL). Diisopropylethylamine (0.10 mL) was added, and the reaction stirred at 10 min at room temperature. LCMS showed complete conversion of deprotected 125. The reaction was acidified with AcOH (0.5 mL), and the reaction mixture purified by preparative HPLC (15% to 85% acetonitrile in water with 0.2% AcOH) to provide 22 as the acetate salt (12.7 mg, 0.00594 mmol, 68% yield). LCMS = 1038.7 [(M + 2) / 2].Preparation of muDS6-DM1 Cytotoxic Conjugate (0365) The muDS6 antibody (8 mg/ml) was modified using 8-fold molar excess of N-succinimidyl-4-(2-pyridyldithio)pentanoate (SPP) to introduce dithiopyridyl groups. The reaction was carried out in 95% v/v Buffer A (50 mM KPi, 50 mM NaCl, 2 mM EDTA, pH 6.5) and 5% v/v DMA for 2 h at room temperature. The slightly turgid reaction mixture was gel-filtered through a NAP or Sephadex G25 column (equilibrated in Buffer A). The degree of modification was determined by measuring the absorbance of the antibody at 280 nm and the DTT released 2-mercaptopyridine (Spy) at 280 and 343 nm. Modified muDS6 was then conjugated at 2.5 mg Ab/mL using a 1.7-fold molar excess of N2?-deacetyl-N-2?(3-mercapto-1-oxopropyl)-maytansine (L-DM1) over SPy. The reaction was carried out in Buffer A (97% v/v) with DMA (3% v/v). The reaction was incubated at room temperature overnight for 20 h. The opaque reaction mixture was centrifuged (1162×g, 10 min) and the supernatant was then gel-filtered through a NAP-25 or 5300 (Tandem 3, 3×26/10 desalting columns, G25 medium) column equilibrated in Buffer B (1×PBS pH 6.5). The pellet was discarded. The conjugate was sterile-filtered using a 0.22 muM Millex-GV filter and was dialyzed in Buffer B with a Slide-A-Lyzer. The number of DM1 molecules linked per molecule of muDS6 was determined by measuring the absorbance at both 252 nm and 280 nm of the filtered material. The DM1/Ab ratio was found to be 4.36 and the step yield of conjugated MUDS6 was 55%. The conjugated antibody concentration was 1.32 mg/mL. The purified conjugate was biochemically characterized by size exclusion chromography (SEC) and found to be 92% monomer. Analysis of DM1 in the purified conjugated indicated that 99% was covalently bound to antibody. In FIG. 20, flow cytometric binding of the muDS6-DM1 conjugate and unmodified muDS6 to Caov-3 cells shows that conjugation of muDS6 results in only a slight loss of affinity.

Molecular Weight:738.3
XLogP3:2.2
Hydrogen Bond Donor Count:3
Hydrogen Bond Acceptor Count:11
Rotatable Bond Count:8
Exact Mass:737.2748936
Monoisotopic Mass:737.2748936
Topological Polar Surface Area:158
Heavy Atom Count:50
Complexity:1340
Defined Atom Stereocenter Count:8
Defined Bond Stereocenter Count:2
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes