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