pH + tablet coating Flashcards
3 types of coating
Sugar
Film
Compression
Polymers for enteric coating
Cellulose acetate pthalate (CAP) - a ph-sensitive cellulose derivative
Methacrylic acid copolymers - non cellulose derivative
What polymers used for film coat?
Cellulose derivatives
What are the constituents of film coating?
Polymer
Vehicle
Plasticiser
Pigments
Name the 7 reasons for coating tablets
Protect from environmental factors
Mask bitter or unpleasant taste
Ease of swallowing
Mask batch wise differences in tablet colour
Coatings coloured for easy identification
Give additional mechanical strength
Control when and how long a drug is released
MUPS
Multiple unit pellet system - enteric coated particles compressed into a tablet
Why does the polymer coat need to be more flexible
Because of the Compression forces that are applied in the tableting forces
Best suited enteric coating polymer for MUPS
Methacrylic acid copolymer
What is CAP
pH-sensitive cellulose derivative
Where would enteric coat dissolve
Duodenum - to allow tablet to disintegrate
Why are small enteric coated particles preferred
They easily pass through pyloric sphincter without stomach emptying
Why are enteric coats used?
Prevent tablet disintegrating in the stomach
