Hi friends,

Very good morning. I need your kind help. I am using following pilot experimental conditions for study of drug release kinetics.

a) Time points 0-96 Hrs (12 time points). Encapsulated nano-particles equivalent of 200 microgram BSA are incubated in 1 ml PPB buffer (pH 7.2)/ Acetate buffer (pH 5.0) for each time point separately. After fixed time points, supernatant is collected by centrifugation and estimated for BSA release via ELISA.

b) Time points 0-96 Hrs (12 time points). Encapsulated nanoparticles equivalent of 3000 microgram BSA are incubated in 15 ml PPB buffer (pH 7.2)/ Acetate buffer (pH 5.0) on a magnetic stirrer. After each time point, 1 ml sample is removed from the vial and supernatant is collected by centrifugation estimated for BSA release via ELISA. Pallet of the particles is re-suspended in fresh buffer and added back to 15 ml vial to maintain the constant volume.

        I have some confusions regarding the BSA release kinetics calculations from chitosan nano particles. In the literature, people have used both the individual as well as cumulative methods of drug release study.

1) What is the basic principle of drug release calculations individually at each time point and cumulative drug release across different time points?

2) How do we calculate cumulative drug release and which one is better in terms of the amount of useful information?

(a) When known amount of drug loaded particles are individually incubated (in separate tubes) for different time points, in fixed volume of release buffer and buffer is not replaced by fresh buffer?

(b) ) When known amount of drug loaded particles are incubated (in one tube) for different time points, in release buffer and buffer is replaced by fresh buffer every time a sample is taken out?

3) Do we need to essentially calculate cumulative drug release across different time points? Or can we calculate drug release at each time point individually and then sum it up?

4) I will greatly appreciate if you could suggest me the stepwise calculations and explanation of critical steps (i.e. why we multiply each time point protein release amount by total volume of buffer or sample buffer) to calculate the drug release and a relevant book or other study material site or source. 

Thanks in anticipation,

Regards and best wishes,

Rajesh Gupta