soft capsules Flashcards
how are soft capsules made up?
Principal materials: gelatin(Softgels), thermoplastic potato starch (VegaGels)
•Continuous shell surrounding a liquid fill
what kind of administration are soft capsules suitable for?
oral- swallow bitten sucked
or inhilation- from cloth/ steam
rectal
what does the shape of the soft capsule tell you about it?
the route of admin
round/oval/oblong-oral
torpedo- rectal or vaginal use
tube like- topical
what are the advantages of soft capsules compared to tablets?
no compression
optimum uniformity content
longer shelf life for drugs prone to oxidation
what is the composition of soft gelatin capsules?
- Higher elasticity than hard capsules and defined viscosity
- Plasticizer (glycerol 15-30 %, often combined with sorbitol or PEG)
- Water (water to dry gelatin1:1)
- Colourants, pigments
- Film coating (enteric coating: 4% cellulose acetate phthalate)•Storage and packaging related to composition of capsule shell
what is the composition of Thermoplastic potato starch soft capsules?
- Plasticizer (glycerol, sorbitol, maltitol)
- Anti-caking agent (glycerylmonostearate)
- Water (final equilibrium concentration 30 – 50 %)
- Final protective coating (vegetable wax)
what are the two ways you can manufacture soft capsules?
globex method
rotatory die method
describe the globex method?
- Lipophilic fill & shell formulation stored in separate containers – both warm (in liquid state)
- Fill and shell material pumped through a double capillary (fill is the inner one)
- Pulsing action to give predetermined fill volumes, separating individual dose units
- The high surface tension gives rise to droplets (reduce surface area) –seamless round capsules
- Capsules fall through immiscible cooling bath (often liquid paraffin, 4 oC)•Capsules collected, washed and dried
what do you consider when filling soft capsules?
- When filling - temperature, viscosity, surface activity
- Suspensions
- Pastes
- Oily liquids: vegetable oils, liquid paraffin
- Self-emulsifying systems (poorly water soluble drugs, self emulsify in contact with aqueous media to form fine dispersion e.g. mix of oil, surfactant and co-surfactant
- Liquids miscible with water:PEGs 400-600 (liquid when low mwt)GlycerolIso-propanolTriethylacetateliquid triglycerides
what would you consider when filling Solid and semi-solid materials?
Waxes
Triglycerides
Higher molecular wtPEGs
Hydrogenated fatty oils
what are the general advantages of filling soft capsules?
- Increased bioavailability of poorly soluble drugs
- Prevention of partial dissolution and re-crystallisation of drugs
- Masking bad taste, odour
- Safe and simple manufacture
what are the limitations for filling materials?
- Drugs or excipients containing water or other substances that dissolve gelatinor starch, or change their properties
- Emulsions (o/w or w/o, unstable and will crack during manufacture due to loss of water)
- Surfactants – affect sealing of capsule
- pH limits for gelatin soft capsules
what are the ph limits for soft gelatin capsules?
< 2.5, hydrolysis of gelatin– capsules could leak
> 7.5, brown discolouration and reduced solubility of gelatin
what is your choice of filling affected by?
for drugs soluble in acidconditions (i.e. stomach):Water miscible filling, drug dissolved or suspended
For drugs practically insoluble in acidconditions: Drug must be dissolved in filling e.g. Improved bioavailability of 20 mg temazepamdose (drug dissolved in PEG)