Centrifuge the nanoparticles and analyze the supernatant for drug in solution. That will tell you how much is associated with the polymer (which I assume you mean to be polymer-based nanoparticles).

Dear all, in the following paper different experimental techniques have been used to evaluate the encapsulation efficiency. My Regards

https://doi.org/10.1016/j.biomaterials.2006.03.006

Hi Mahesh,

If you obtain a clear solution during nanoencapsulation, you can use TEM to ensure nanoparticles were formed. You can equally use dynamic light scattering for size measurement. Most nanoparticles are formed by antisolvent precipitation technique and precipitates are usually separated after high speed centrifugation. If you have a clear solution after nanoparticle formation, you might need to modify methodology like choosing a solvent in which various constituents that formed the nanoparticles have varying degree of solubility. In that way, encapsulated compound can easily be separated from the free compound and macromolecular encapsulating agents.

I use Fluroscence or Uv spectroscopy. First make a standard curve for the drug you are using, by UV or fluorescence measurements. Then check the fluorescence / Uv of your drug loaded polymer nanoparticle. Then from the standard curve get the concentration that your nanoparticles are incorporating. Then using the drug loading efficiency formula you can calculate the rest. Of course do remember to note down the amount of drug you wete using during drug loading.

Res Pharm Sci. 2017 Feb; 12(1): 1–14.

doi: 10.4103/1735-5362.199041

PMCID: PMC5333474

PMID: 28255308

Development of a nanoprecipitation method for the entrapment of a very water soluble drug into Eudragit RL nanoparticles

Sara Salatin,1,2 Jaleh Barar,1,3 Mohammad Barzegar-Jalali,3 Khosro Adibkia,3,4 Farhad Kiafar,3,5 and Mitra Jelvehgari3,4,*

Author information Article notes Copyright and License information Disclaimer

This article has been cited by other articles in PMC.

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Abstract

Rivastigmine hydrogen tartrate (RHT), one of the potential cholinesterase inhibitors, has received great attention as a new drug candidate for the treatment of Alzheimer's disease. However, the bioavailability of RHT from the conventional pharmaceutical forms is low because of the presence of the blood brain barrier. The main aim of the present study was to prepare positively charged Eudragit RL 100 nanoparticles as a model scaffold for providing a sustained release profile for RHT. The formulations were evaluated in terms of particle size, zeta potential, surface morphology, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). Drug entrapment efficiency and in vitro release properties of lyophilized nanoparticles were also examined. The resulting formulations were found to be in the size range of 118 nm to 154 nm and zeta potential was positive (+22.5 to 30 mV). Nanoparticles showed the entrapment efficiency from 38.40 ± 8.94 to 62.00 ± 2.78%. An increase in the mean particle size and the entrapment efficiency was observed with an increase in the amount of polymer. The FTIR, XRD, and DSC results ruled out any chemical interaction between the drug and Eudragit RL100 polymer. RHT nanoparticles containing low ratio of polymer to drug (4:1) presented a faster drug release and on the contrary, nanoparticles containing high ratio of polymer to drug (10:1) were able to give a more sustained release of the drug. The study revealed that RHT nanoparticles were capable of releasing the drug in a prolonged period of time and increasing the drug bioavailability.

Keywords: Rivastigmine hydrogen tartrate, Nanoparticles, Eudragit RL100, Nanoprecipitation

Hello Mahesh Funde,

thank you for asking this very interesting technical question on RG. Here I will share some reference papers that will help you to find drug encapsulation efficiency.

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Loading efficiency gives you an idea about the %drug that is successfully entrapped/adsorbed into nanoparticles.

It is calculated as follows: %EE = [(Drug added - Free "unentrapped drug")/Drug added] *100 Example: If the %EE is 30%, it means that 30% of your drug is entrapped into the nanoparticles.

Drug loading content helps you to deal with nanoparticles after their separation from the medium and to know their drug content.

It is calculated using the following equation: Drug loading content (%)= (Weight of drug in nanoparticles/ Weight of nanoparticles)*100 Example: If the loading capacity is 30%, it means that 30% of the nanoparticle's weight is composed of the drug! i.e. Each 1 mg nanoparticles contains 0.3 mg drug.

Hope this will help you, good luck with your work!