Gelatin soft capsule formulation
Formulation Guideline

Gelatin soft capsule formulation

Low hygroscopic and not migrating gelatin plasticizer: POLYSORB® 85/70/00 sorbitol-sorbitan


Glycerin has been historically used to plasticize soft gelatin capsules (softgels). However, glycerin presents major drawbacks: a high hygroscopicity and a capacity to migrate out of the gelatin network toward the liquid fill. POLYSORB® 85/70/00 sorbitol-sorbitan solution is a good complementary to glycerin to plasticize gelatin with lower hygroscopicity and significant reduction of migration phenomenon. 



Functionality of the ingredient

Formulation in the melter

by weight in dried capsule shell (8% water)

180-bloom limed bone

Film-forming agent


61.4of the capsule shell

POLYSORB® 85/70/00 


11% (dry substance)

15.3of the capsule shell




15.3% of the capsule shell



8% of the capsule shell

PEG 400 based drug preparation

Capsule filler

100% of the filling



  1. Blend the gelatin, plasticizers* and water in the melter. 
  2. Heat until the gelatin melts (end point 60°C).  
  3. Vacuum for full de-aeration. 
  4. Maturate for minimum 6 hours** at 60°C. 
  5. Process the melt through your softgel equipment, dry to mass constancy (typically tumble dryer followed by tray drier at 20% ERH /25°C).   

* The optimal plasticizers ratio should be adapted on the gelatin grade, the capsule size and the fill system. Pigments could be added, if needed. 

** The water content might be adjusted to meet internal viscosity limits. 

Comment on Roquette product benefits 

POLYSORB® 85/70/00 partially dehydrated sorbitol-sorbitan solution has remarkable compatibility with gelatin ensuring no migration over time, thereby preventing any defects like the graining observed when crystallizing plasticizers are used or leaching phenomena either into the filler media or at the surface of the softgel. 

In addition, POLYSORB® 85/70/00 is less hygroscopic than glycerin. This property offers key advantages that include shorter drying time after production that reduces production costs and higher storage stability. 

For more information, please refer to the following article published in Tablets & Capsules (April 2019, volume 13, number 3, page 37) accessible here: 



This formula is a guideline for recommended use of our products; it does not imply consent to their use in violation of existing patent(s).  
These details are for information only, and we believe them to be reliable.

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