Custom Synthesis
If additional product optimization is required, we can provide developmental input and custom synthesis. A large percentage of our polymer business at DURECT is devoted to the development of polymers with customized characteristics.
For example, we have worked closely with clients to:
- Increase polymer solubility. For example, solubility is a key attribute for microsphere products. To meet customer needs in this area, we have used our synthetic expertise to manufacture 50:50 poly(DL-lactide-co-glycolide) with increased solubility in common solvents.
- Optimize release kinetics, hydrophilicity, and degradation by tailoring end group chemistries, such as hydroxyl, ester, free carboxylic acids and PEG.
- Tightly control polymer molecular weight.
- Vary monomer ratios to give desired drug release profiles and excipient degradation times.
Subtle changes in molecular architecture can have a profound effect on degradation and drug release rates. For example, altering the polymer end groups can affect water uptake and degradation rate. Typical examples are shown below. Our scientists can help you determine the characteristics necessary for your application through developmental input and custom synthesis. Please contact Technical Support to discuss your needs.
Initiator-Polymer End Group Effects
| Initiator | End Groups | Effects |
|---|---|---|
| Monofunctional alchohol | Ester and Hydroxyl | Slightly hydrophilic |
| Diol | Hydroxyl and Hydroxyl | More hydrophilic |
| Water or α-hydroxyl acid | Carboxylic acid and Hydroxyl | More hydrophilic; increase water uptake and degradation rate |
| Polyethylene glycol (PEG) | PEG and Hydroxyl | Most hydrophilic |
