Hello,

Drug Loading Capacity (%): (Weight of the entrapped drug inside the gel/Total weigh of the gel)*100

Entrapment or encapsulation efficiency (%): (Weight of the entrapped drug inside the gel/ Total Weight of the initially added drug)*100

Drug Release (%): (The amount of solubilized drug in the release medium/Initial weight of the entrapped drug)*100

Drug release percentage is measure at each predetermined time interval, while the cumulative released amount is referred to the sum of all measured amounts and will be calculated at the end of the predetermined release period.

Thank you for your immediate response. To make it more clear can you please tell me the difference between (Weight of the entrapped drug inside the gel) and (The amount of solubilized drug in the release medium)? @ Abouzar Karimi

''Weight of the entrapped drug inside the gel'' and ''The amount of solubilized drug in the release medium'' can both be calculated from UV absorbance values by using Beer Lambert Law A=ecl ? Kindly share any reference book or paper if possible. Abouzar Karimi

When calculating encapsulation efficiency, you must acquire maximum solubilization of the entrapped drug, which is usually carried out by applying intentional forces on the gel structure, such as destruction of the gel matrix, centrifugation, etc. Whereas in the release study, the amount of solubilized drug is determined by the natural forces that are presented in the release medium, such as diffusion or enzymatic degradation of the gel structure.

Yes, they are both calculated from UV absorbance values by using Beer-Lambert Law.

I apologize, but I don't have a reference specifically related to your topic. However, they are both pretty straightforward procedures which you can find in most related studies.

I want to check the drug release percentage in following experiment. 2mg initial drug, 25mL buffer solution, 2 mL solution was taken out to check absorbance by UV and replaced with 2mL fresh buffer solution, What will be the dilution factor for the above calculation when calculating amount of solubilized drug in the release medium by the following formula:

Amount of drug released (mg)= [Concentration X Dilution factor X Volume of Dissolution medium] / 1000 Abouzar Karimi