Generally, the alternate method is used where we estimate the %free drug content and inversely get the encapsulated drug content.

Firstly take around dried samples equivalent to 10 mg of drug in formulation and then used either methanol 10ml or go for ethanol:water (60:40) 10 mL or any solvent (in which your drug only soluble) in a centrifuge tube and then centrifuge it at 10,000 rpm for 15 mins. Then draw the supernatant and dilute it further and then estimate at your drug's wavelength for content.

This will give you free drug content, hence you can claim dat remaining drug are encapsulated.

If in case you need encapsulated drug data too, then, firstly do the above method and then separate the settled particles and then wash with drug soluble solvent several times, and then take that particles, add in tubes and then add solvent in which your drug and polymer, both are soluble. then centrifuge it at 20,000 rpm for 15 mins (twice), then draw the supernatant, then check the abs using UV and find the encapsulated drug content.

Hi,

The theoretical percentage of drug loading (TDL) was calculated using the following equation.

TDL = (Weight of drug added (g)/Weight of polymers and drug added (g)) x 100 (1)

For eg if you use 2 g of drug and 8 g of polymer, then the theoretical loading is

2/10 x 100 = 20, hence the theoretical loading is 20% w/w.

Assume that, during analysis each gram of microspheres contains 100 mg of drug.

Then actual loading is 100/1000 x100 = 10% w/w.

The percentage of drug entrapment efficiency (DEE) was calculated according to the following

DEE = (Experimental drug loading/Theoretical drug loading (TDL)) x 100 (2)

As per the above example the DEE = 10/20 x100 = 50% w/w.

Lets assume the yield of the microsphere is 9 g. Remaining one gram lost during the manufacture.

In the 9 gm, we have 10% of drug that mean 900 mg of the drug.

Encapsulation efficiency = total amount of drug in the yield (g)/ actual amount of drug added during microencapsulation (g) x 100

hence, 0.9/2 x 100 = 45% w/w . It means only 45% of employed drug was encapsulated and remaining 55% was lost during washing/recovery etc.

Hope this will help you.

Can anyone help with an entrapment efficiency/encapsulation efficiency calculation? - ResearchGate. Available from: https://www.researchgate.net/post/Can_anyone_help_with_an_entrapment_efficiency_encapsulation_efficiency_calculation [accessed Feb 18, 2016].

Please Check this Below link

https://www.researchgate.net/post/is_the_value_of_encapsulation_efficiency_is_usually_greater_than_that_of_loading_capacity_for_drug_loaded_nanoparticles

Suraj Choudhary, taking dried samples equivalent to 10 mg of drug in formulation is necessary? Cannot we take dried samples equivalent to 5 mg of drug? Can you sen the reference for the methods you told me?

Thank you.