i am preparing nanoparticles, drug is hydrophilic and entrapment efficiency is very low. If i find the drug release by dividing with the total drug taken its giving very low drug release so is it possible to find drug release by dividing with the total drug entrapped? Kindly send if there is any reference for it.
1. You should determine the actual drug content of you nanoparticles by:
% drug content= (actual drug content/theoretical drug content) x 100
2. Then, after performing the release studies, to get the % release:
% release= (amount of the drug release/ actual drug content) x 100.
Lot of papers that describe calculation of NP content..
The attached article may help you.
Suppose in a formulation I add 20 mg of drug and 200 mg of Polymer.
Theoretical drug load = 20/220= 9.09 %
Actual drug load = 5/220 = 2.27 %
% drug content= (actual drug content/theoretical drug content) x 100
= 2.27/9.09 x 100= 24.9 %
% drug release= (amount of the drug release/ actual drug content) x 100.
=1/ 2.27 x 100 = 44.05
Kindly comment are my calculations correct?
The actual drug content is 5 mg, and the amount releaesed is 1 mg..
Simply, the % released=( amount released/actual content ) × 100
From eqation Y = mx + b we find concentration
Conc × dilution factor = conc 1
conc1/ weight of nanoparticles = Actual drug content
Kindly explain how you are taking 5mg as Actual drug content.
Thanks in anticipation.
You mentioned that before.
anyway, if the drug release amount is (N mg) and the actual drug content is (M mg),
the % release = (N/M) x 100.
Dear Giulia
what you have done s correct (showed calculations)
% release should be based on actual content rather than original drug you have taken.
When that drug is not in formulation only why you need to consider. So the caluclations what you showed is correct.
I would recommend that you try to microencapsulate the drug particles in a stirred suspension in a nonsolvent to form a thin film coating of a hydrophobic glassy material from low concentrations of monomers such as hydroxyethylmethacrylate with a proportion of diacrylate or dimethacrylate such as (ethyleneglycol) dimethacrylate as a surface crosslinking agent. To catalyse the vinyl polymerization you could use UV light or a low dissolved concentration of solvent-soluble free-radical generating initiator which releases radicals at moderately raised temperatures (100C). These compounds are usually peroxides or azo compounds which will be described in most polymer textbooks.
This should provide a slow, constant release, formulation which could be easily isolated by centrifugation. The reservoir particles of solid drug with a thin membrane is an ideal constant release formulation for which the half-life of release would be controlled by the membrane thickness which can be controlled by the number of times you repeat the coating process.
Good Luck!
Emeritus Professor Neil B Graham
It's better to determine drug content of nano particles. There after perform drug release study with the equivalent amount of nano particles.
Along with all previous answers... consider correction factor every time if your are doing replenishment of your disso medium.
All drug may not be entrapped in carrier system during NP preparation hence its mandatory to find how much drug exactly incorporated in NP against total amount of drug added by you in preparation.
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