Application Note

Solutions For Challenging Compounds Using Softgel Innovation

Source: Catalent
Better Development And Formulation Solutions For Challenging Compounds Using Softgel Innovation

Executive Summary

For the last 80 years, softgel technology has brought poorly water soluble and/or permeable BCS II & IV compounds to market by improving their bioavailability. Gelatin has predominantly been the ingredient of choice for the softgel shell material for lipid base formulation; its success is demonstrated by the wide range and number of softgel products available on market. The significant interest in semi-solid systems for the potential of extended release profiles has prompted researchers to develop alternative encapsulating systems. Catalent Pharma Solutions has lead research studies to establish that the plant polysaccharides-based OptiShell™ technology can accommodate a wider range of excipients and more molecules. It enables:

  • Encapsulation of fill formulations at high temperature (up to 70°C) for semi-solid and highly viscous fill formulations
  • Compatibility with a wider range of fill excipients for enhanced drug bioavailability and stability

The Challenges

It is challenging to find optimal development solutions to enhance bioavailability for drug compounds contained within complex fill formulations 

  • High melting point fill formulations or semi-solid, highly viscous fills
  • Wide range of compatible fill excipients to enhance bioavailability and stability

The Catalent Solution

Researchers have developed OptiShell capsules using a combination of iota-carrageenan (extracted from red seaweed) and modified starch for the shell’s formulation.  Studies have shown that OptiShell capsules possess similar stability as conventional gelatin-based shells with regard to processing, manufacturing, and dissolution characteristics. In addition, they are amenable to a larger variety of lipophilic, hydrophilic, and semi-solid fills.

Figure A and Table A show that the OptiShell formulations were stable and encapsulated in the “hot fills.” The final dosage form had minimal migration of fill material into the shell. At room temperature, the fill material stayed in a semi-solid state. The shell appeared to be uniform and retained softgel characteristics.

Figure A OptiShell™ capsules containing semi-solid fill formulations

A study was conducted to compare OptiShell and gelatin shells for compatibility with lipophilic and amphiphilic ingredients. Ingredients that are semi-solid at room temperature and had passed the initial compatibility studies were used for encapsulation trials using OptiShell encapsulating films and a hot filling process.  The result showed that the ingredients possessing a high proportion of monocaprylate or monocaprate groups exhibited improved stability when dosed into OptiShell capsules. (Figure B and Table B). It was also observed that polysaccharide based shells maintained their dissolution characteristics throughout accelerated and long term stability studies.

Figure B Effect of short-term storage, at 40°C, of capsules containing caprylic acid, on the physical stability of the capsule shell



Catalent’s novel plant polysaccaride-based OptiShell capsule in conjunction with its softgel manufacturing expertise offers a faster path to market for a wider range of molecules by offering increased compatibility with different types of fills, such as lipophilic, hydrophilic, and semi-solids. OptiShell technology has also shown amenability with currently used manufacturing processes which can result in better scalability.

Discover more solutions at
Global + 1 888 SOLUTION (765-8846)
EU 00800 88 55 6178