What Are Softgels Made Of?

Usually oblong and translucent softgel capsule not only give an appealing look but its smooth finishing allows easier swallowing. Discussed below are the major components of the softgel capsule.

Composition of softgel capsule

Gelatin

Ⅰ.AnimalSource

Similar to hard gel, softgel also has gelatin as a prime ingredient. A large number of gelatin matrix formulations are available which is depending on the nature of the liquid fill matrix.

Gelatin is derived from an acid-treated precursor termed Type A Gelatin, whereas from an alkali-treated precursor known as Type B Gelatin.

TYPE A	TYPE B
Obtained from bones	Obtained from pork skin
Derived from acid-treated precursor	Derived from alkali-treated precursor
Iso-electric point in the region of pH 9	Iso-electric point in the region of pH 4.7

Table: Difference between Type A and Type B gelatin

The protein structure of gelatin is composed of various polypeptide chains. E.g., a-chain, β- chain (dimer of a- chain), ℽ- chain (trimmers of a- chain). Here, a athe chain has one peptide that connects with two peptide chains of β- chain. A ℽ- chain is composed of three peptide chains. Gelatin has a high concentration of ℽ- chains hence exhibiting higher gel strength.

The choice of gelatin is based on types, grades, consumer preference, and technological issues. For example:

Raw Material	Grade
Bovine and Porcine Bone	B
Bovine Hide	B
Bovine Bone	A
Pigskin	A
Blend of Pigskin and Bovine/ Porcine bone and Bovine hide	A/B

Ⅱ.NON- AnimalSource

Pullulan

Pullulan is a natural polysaccharide used to make a vegan capsule. Pullulan is a pure natural water-soluble polymer made of corn starch or sugar. This is generated from starch with the help of the fungus Aureobasidium pullulans. The gelatin forms from this source are safe to use and widely acceptable by those with restricted diets.

Pullulan is a water-soluble exo-polysaccharide with an exceptional characteristic e.g., co-existence of α-(1→4) and α-(1→6) linkages.

Hypromellose

Hypromellose or hydroxypropyl methylcellulose (HPMC) is a clear, tasteless substance appropriate for vegetarian-based softgel capsules. This is made from raw cellulose which is an acceptable source across the globe for controlled delivery of drugs in oral dosage forms.

Hypromellose is a hydrophilic, non-ionic, and viscoelastic polymer and fiber which is considered safest for human consumption. HPMC or Hypromellose is derived from a softwood tree, primarily pine and spruce that are cultivated and harvested in the south-eastern United States.

GuarGum

Guar gum is also known as vegetable gum. It is low in calories and has high in soluble fiber that produces thickening effects in the capsule. Typical guar gum is composed of 36.6% galactose anhydride as well as 63.1% mannose anhydride.

Guar gum is obtained from legumes known as guar beans. The external husk of the beans is removed where a central starchy endosperm is collected, and ground into a fine powder.

Carrageenan

It has been traditionally used in cooking for hundreds of years. Due to its thickening properties, it has been considered a gelatin alternative in various applications.

Carrageenan is a natural polysaccharide obtained from Red seaweed or Irish moss, Chondudrus cripus, Eucheuma, and Gigartina stellata. This is composed of a high molecular weight with repeated units of galactose and 3,6-anhydrogalactose, both sulfated & non-sulfated joined by alternating α-1–3 and β-1–4 glycosidic linkages.

Pectin

Pectin is a water-soluble fiber present in fruits and vegetables and is commonly used as a thickener. Besides this, pectin also has therapeutic effects for heartburn, cholesterol, and high- triglycerides. Pectin has a complex mixture of polysaccharides comprised of a galacturonan backbone with variable proportions that can be methyl esterified.

OtherIngredients

Plasticizer

Plasticizers are used to enhance the mechanical integrity of the shell of a softgel capsule. Capsules require a non-volatile plasticizer in water to improve elasticity. A capsule shell shrinks after the removal of water molecules, the plasticizer is a key component that minimizes the brittleness and cracking.

Examples

• Polyalcohol
• glycerol
• sorbitol
• PEG

Colorant

Color may be incorporated into softgel capsules to increase effectiveness and attractiveness. Also, opaque capsules protect the pharmaceutical active content from light and UV radiations. Thus, colors ensure physical stability and reduce the risk of free radical formation. This will make the softgel capsule remain effective for a longer time.

Example

• Soluble dyes (Tartrazine, sunset yellow, Indigo Carmine)
• Water Insoluble Pigment (Cryptoxanthin, capsorubin, β- carotene, violaxanthin, etc)

Preservative

Preservatives are added to softgel capsules to protect them against microbial growth and the formation of mold in gelatin solution during storage.

Example

• Potassium sorbate
• Methyl, ethyl, & propyl hydroxybenzoate

Flavour

A flavoring agent is not a frequently used component in softgel capsules. Though, it is used to enhance digestion, and patient compliance, and to mask the unpleasing odor.

Example

• Vanilla
• Apple
• Orange
• Mango, etc.

Opacifier

Opacifiers ensure high opacity and efficient protection of capsule fill against photodegradation. Furthermore, a unique brightness enhances the brand’s visual identity.

Example

• Titanium dioxide

Water

You can’t ignore the importance of water as it serves as a solvent to make molten gelatin mass with a viscosity at 60–70°C. Furthermore, its ratio with dry gelatin may vary from 0.7 to 1.3. This is depending upon the viscosity of the gelatin that is being used. The water content may be evaporated by drying after capsule formation. The final moisture content ranges from 4 to 10%.

COMPONENTS	ROLE	CONTENT (%W/W)
Gelatin	Polymer	66.3
Glycerine	Plasticizer	33
Parabens	Preservative	0.1
Colour	Colourant	0.1
Titanium dioxide	Opacifier	0.5
Water	Solvent	q.s. (0.7–1.3 × of gelatin

Composition of Softgel Capsule