Capsules Flashcards
Why are capsules used?
For taste masking
Easy to formulate
Can enhance stability
Can be opened (if not MR)
Why is gelatine used for hard capsules?
Non-toxic
Easily prepared
Soluble in gastric fluid
Good film former
Reversible phase change at just above ambient temperature
What are V-caps made of?
Hypromellose
What size are hard gelatine capsules for humans?
1, 0 or 0el
What fillings cannot be used in hard gelatine capsules?
Water and aldehydes
Aldehydes cause tanning which results in a leathery texture
What are the criteria for powder formulations for HCGs?
Formulation must flow well
Degree of cohesiveness required but not too much to prevent sticking
What is the flooding technique?
Dose contained within the full capacity of capsule body
How is the maximum capsule fill weight calculated?
Max capsule fill weight = tapped bulk density/capsule volume
How is the capsule volume required calculated?
Capsule volume required (ml) = required fill weight (g) /tapped bulk density(g/ml)
What can tapped bulk density not be used for?
Liquid filled capsules
Why are tablets encapsulated?
To blind in a clinical trials
For special release dosage forms
To separate incompatible ingredients
For tamper evidence
How do flexible gelcaps work?
Stretched around the caplet and assume the shape of the caplet at the conclusion of the cold shrink process
What API factors affect bioavailability?
Dose
Wetability
Solubility
Rate of dissolution
Flowability
What formulation factors affect bioavailability?
Type of formulation
Specific exciepients used
When is an insoluble diluent used in capsules?
With a readily soluble API to avoid competition for GI fluid
When is a soluble diluent used?
With a poorly soluble API to create a porous plug when in contact with GI fluid and increase dissolution rate
What are soft gelatine capsules composed of?
Gelatine - 35-50%
Glycerol 15-30%
Colours
Flavours
Water
How are single piece capsules produced?
Manufactured and filled at the same time
Liquid is injected into the die pocket of die rollers to produce soft gel capsules
What are the limitations of soft gel capsules?
Specialist equipment needed for filling
Development is difficult and complex
Production would have to be outsourced
What are advantages of liquid filled capsules over tablets?
API is in solution or fine suspension so dose uniformity is not a issue
API has limited contact with moisture, air and heat
Why do liquid filled capsules have better bioavailability than solid dosage forms?
Acid soluble drugs are in solution
Acid insoluble drugs form a suspension with large surface area s go back into solution quickly
