Controlled Release Formulations - Pharmacokinetics

Controlled Release Formulations

·        Aim is to prolong short acting drugs, to reduce daily dose frequency

·        Also a drug company ploy: introduce slow release formulation to extent patent

·        Good points:

o  Increased compliance 

o  ¯Side effects (but probably also decreased therapeutic effects)

·        But:

o  Often more variability in plasma fluctuation. Eg Slower absorption + variations in 1^st pass metabolism ® wider variation in clinical effect 

o  Effect of variation in gastric emptying reduced

o  Adhesive patches cause skin reaction in 30%

o  Fixed dose: harder to titrate 

o  ­Cost