Routine Synthesis Related Questions
What is Routine Synthesis and how is it different from the Custom Bioconjugation Service?
Routine Synthesis is a standardized custom bioconjugation service that CellMosaic does routinely for our customers. You may see Routine Synthesis under various types of molecules. All Routine Synthesis services have their individual service codes and may have options to choose from online, similar to ordering standard oligo and peptide synthesis. For example, Customers can place the order online for ADC routine synthesis with their choice of linkers, reaction scale, purification and characterization, and formulation methods. These services can usually be completed within 2-3 weeks.
Other non-standard Custom Bioconjugation Services generally require more input from the customer and a quote generated by CellMosaic. The order cannot be placed directly online. The timeline for completing the services is usually longer than a Routine Synthesis.
RS0001: Routine Small-Scale ADC Synthesis & RS0002: Routine Medium and Large-Scale ADC Synthesis
The notes on the website mention that the conjugation reaction is optimized for DAR4. Typically, how much of the product is DAR4?
Standard synthesis will target an average of four (4) drugs per antibody molecule based on the thiol assay. However, between 3 to 5 drugs per antibody molecule may be obtained.
How do you calculate DAR for MMAF payload?
VC-PAB-MMAF has UV absorbance at 248 nm and can be used for calculating the loading. Depending on the separation of your ADCs by HIC, you may be able to use HIC to calculate the DAR of the ADC made with Mc-MMAF and Mc-VC-PAB-MMAF. You can always use MS to get the DAR calculation. You can go to this table on our website to check the recommended analysis method for DAR determination for various drugs.
For the routine synthesis, would it also be possible to purify the DAR4 peak or would it just be an analytical HPLC run for DAR profiling?
The optional HIC HPLC is an analysis run, not for purification. Of course, if the analytical HIC HPLC shows separation, we can provide additional HIC purification services to purify the DAR4 peak or collect high DAR products.
The notes on the website mention that the ADC synthesis is done in pyrogen-free conditions and is good for in vivo studies. Could you quantify and guarantee the product has endotoxin below a certain level?
There are slightly different stringent requirements for the small- and large-scale ADC synthesis based on the application.
RS0001 (3-10 mg, small-scale ADC preparation) uses sterilized buffers, pyrogen-free pipette tips, and tubes.
RS0002 (30-200 mg, medium- and large-scale ADC preparation) uses sterilized buffers, pyrogen-free pipette tips, and tubes. The columns/filters/resins are also cleaned prior to usage. The default is that the final product will be sterile filtrated, aliquoted into non-pyrogenic/sterilized lyophilization vials (5 mg per vial), lyophilized, and sealed under N2 atmosphere.
Yes, we can perform the endotoxin assay in-house. Endotoxin assays are charged a $600 setup fee plus $125 per sample (price as of June 2024).
Yes, we can guarantee that the endotoxin is below a certain level. However, to guarantee this, we will require all of the columns/filters/resins to be cleaned prior to usage. In addition, an optional endotoxin removal step will be quoted in case we need to purify to meet the requirement.
What is the turn-around time?
For RS0001, the routine small-scale synthesis takes 2-3 weeks. For RS0002, the turn-around time is 3 to 4 weeks depending on the scale. MALDI-TOF adds an additional week.