PHAR2823 Lecture Notes - Lecture 3: Methyl Cellulose, Modified Starch, Silicon Dioxide
Document Summary
Ensures a tablet breaks up into small fragments when in contact with liquid, allows for rapid drug dissolution. Starch and its derivatives (>5%) may affect compressibility for dc. Celluloses microcrystalline cellulose (e. g. avicel) at ~10% level. Miscellaneous surfactants and ion exchange resins. Super disintegrant- effective <5%, sodium starch glycolate, croscarmellose sodium, The tablet breaks to primary particles by one or more of the mechanisms. Creating repulsive forces to disrupt bonds between particles. Starch up to 10% in formulation. Sodium starch glycolate cross linked carboxymethyl starch. Colloidal silicon dioxide capable of absorbing ~9 times as much water as starch. Surfactants makes the drug particle surface more hydrophilic > promotes wetting and penetration of liquid into the pores of tablet. Modified starch e. g. sodium starch glycolate. Modified cellulose e. g. methyl cellulose, carboxymethyl cellulose, croscarmellose. If bicarbonate and citric acid are present, chances are the tablet will be effervescent. Reduce friction the powder/granulate die wall during tablet compression and ejection.
