Question

What are the characteristics of diffusion-controlled release systems?

(a) Release the drug along the entire length of GIT

(b) Diffusion of the dissolved drug

(c) Release only at a specific drug

(d) Employ waxes to control the rate of dissolution

I have been asked this question at a job interview.

I want to ask this question from Biopharmaceuticals in chapter Biopharmaceuticals of Drug Biotechnology

Answer 1

Correct answer is (b) Diffusion of the dissolved drug

For explanation: The rate controlling step is the diffusion of the dissolved drug through a polymeric barrier. The drug release rate is never 0. The diffusional path length increases with time as the insoluble matrix gradually depletes from the drug. Two types of diffusion-controlled systems are matrix systems and reservoir systems.