Capsules

Question 1

2 types?

Answer 1

Hard - two piece

Soft - one piece

Question 2

Main materials used in capsules?

Answer 2

Gelatin (or alternative polymers)
Water
colourants
Preservatives 
Plasticisers NEED

Question 3

Two ways of producing gelatin?

Answer 3

From collagen
Via bones - ALKALI - with NaOH - Gelatin B
Via Skin - ACIDIC - acidification to pH 4 - Gelatin A

Question 4

Alkali method of producing gelatin

Answer 4

Treat with NaOH, remove, treat with acid to adjust pH, heat from 50 degrees to boiling, demineralise, filter,vacuum evaporation, drying == Gelatin B

Question 5

What materials do soft gels typically hold

Answer 5

Liquid / semi solid

Question 6

Give examples of plasticisers to make gelatin soft

Answer 6

glycerol
propylene glycol
sorbitol

Question 7

What does the shell of the soft gel capsule contain

Answer 7

gelatin 35-45%
plasticiser
water 40%

Question 8

What advantage does soft gel cap have over hard gels?

Answer 8

Cannot formulate solutions into hard but can into soft gel capsule
- also dont need preservatives

Question 9

Why arent preservaties needed in soft gel compared to hard?

Answer 9

Because it is completely enclosed in one - sealed - so no air can get in in comparison to hard

Question 10

Does soft gel capsules have increased or decreased rate of absorption (& thus bioavailability? Why?

Answer 10

Increased - it is typically in a solution form in the capsule so quicker absorption - dont need to break down into molecules like in hard capsules

Question 11

Advantages of soft gels

Answer 11

Improved bioavailbility/solubility for poor soluble drugs
Swallowing
faster onset of action
Formed, filled, sealed in1 go
- Safer manufacture as no air borne powders
- Completely sealed - no degradation, oxidation, moisture, hydrolysis

Question 12

Disadvantages of soft gels

Answer 12

Specialised and costly equipment e.g encapsulation machines, and need specialist expertise

• High quality gelatin needed
• People reluctant to set up own softgel manufacturing operation and often outsource external softgel manufacturers
• Only a few contract manufacturing organisations that specialise

Question 13

What are the requirements for formulation of soft gels?

Answer 13

Stable physical form of the drug
Fill vehicle that minimises transfer of water from shell into fill
- excipients no interactions with drug /eachother
- Excipients no impurities that may affect dissolution/stability
- Plasticiser
- Inert manufacture environment e.g Nitrogen blanketing for Oxygen sensitive compounds, or Yellow light for photosensitive compounds
- Good drying conditions
- Proper storage conditions

Question 14

Capsules or tablets? what does it depend on

Answer 14

• Company policies .g if always produced tablets, expensive to set up new line with new equipment
• Competitor products e.g if another company makes it, cannot really compete - different formulation
• Equipment available - expertise, difference
• Required unit dose e.g capsules fit larger doses
• Stability
• Compression characteristics e.g large molecules hard to compress

Question 15

How to manufacture hard capsules?

Answer 15

Dip into hot solution, take out, cool down, forms a gel on cooling (unique)

Question 16

Why wouldnt the manufacture for hard capsules work if using HPMC alternative?

Answer 16

Because the hard capsule manufacture relies on the unique property of gelatin forming a gel on cooling, whereas HPMC forms a gel on heating - would need different conditions

Question 17

How are empty hard capsules to be stored?

Answer 17

Storage in controlled temp and humidity
If they are too moist - become too soft as take up water and deform

If too dry - brittle and break/crack

Question 18

Structure of gelatin?

Answer 18

Has polymer chain of amino acids and carboxylic acids
- amino groups are ionisable +
- Carboxylic groups unionisable -
(Amphoteric)
- API and excipients must NOT react with gelatin

Question 19

Properties of gelatin

Answer 19

• Solutions of high conc are mobile (runny) at 50degrees
• changes gel to sol above RT and reversible
• Non toxic
• Soluble at body temp
• Film forming properties are good