Apisolex polymer

Apisolex™ Polymers - Solubility-enhancing polymer for use in bolus injections and IV infusions

Lubrizol’s Apisolex™ GMP, injectable-grade excipient is a safe, polyamino acid-based polymer that enhances the solubility of BSC Class II and IV APIs. When combined with an API and a solvent, Apisolex excipients form nanoparticulate micelles which increase the solubility of most hydrophobic drugs. 

Improve your formulations with Apisolex™ polymer

  • Increases the solubility of hydrophobic APIs by up to 50,000-fold. 
  • Allows high drug loading (up to 40:100 API:solubilizer ratio). 
  • Forms stable, lyophilized drug product that reconstitutes in saline in under 30 seconds.
  • Enables IP protection and 505(b)(2) formulations/lifecycle management.   

Simplify your manufacturing with Apisolex™ polymer

  • Simple formulation techniques - solution mixing or oil-in-water emulsion formation. 
  • Minimal API loss (recovery >90%).
  • Standard, scalable formulation techniques. 

Competitive advantages 

  • Higher drug loading than other solubility-enhancing excipients.
  • Substantially increases achievable concentration of API in water.
  • Non-toxic, non-immunogenic, biocompatible, and biodegradable alternative to PEG. 

We put Apisolex™ polymers to the test:   

Apisolex was found to be effective in solubilizing hydrophobic APIs: 

  • Amphotericin B 
  • Cyclosporin A 
  • Etoposide 
  • Melphalan 
  • Paclitaxel
  • SN-38 

In additional experiments conducted for APIs, BI-0001 – BI-0005, Apisolex polymer increased the drug solubility up to 50,000-fold. 

API Solubility in
Water (mg/ml)
Solubility in Formulation
with Apisolex Polymer (mg/ml)
Solubility Increase with
Apisolex Polymer (Fold) 

BI-00011  20 2,000 100
 8 2,000 250
 0.4 20,000 50,000
 1.2 10,000 8,333
 4 5,000 1,250
 1 APIs for this study were provided by Boehringer Ingelheim Pharm. Inc.

See what Apisolex™ polymers can do for your API. Contact us today.

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To learn more about how Apisolex™ excipients can overcome API solubility issues in parenteral drug delivery, download our information sheet today.