Dear Alien,

A model to study the mechanism of the release of a drug (ibuprofen) from lipid nanoparticles has been investigated and its findings are as follows:

Ibuprofen as a model drug was entrapped in the oily core while Cremophor A25 and Cremophor A6 were used as hydrophilic surfactants in different ratios ranging from 1:1 to 1:0. All the prepared LNC were of comparable particle sizes around 50nm. Varying Cremophor compositions as well as the presence of lecithin, cetyl or stearyl alcohol had no significant effect on the in vitro drug release profiles. However, drug release rates increased significantly with increasing the temperature from 4 to 50 degrees C, i.e. the flux increased from 1.5 to 7microg/(cm(2)min). This was explained by the increased ibuprofen-lipid interactions at reduced temperature where the increased viscosity of the lipid significantly slows down the drug diffusion to the external aqueous phase. In summary, the physicochemical properties of the drug as well as the oil phase have a high impact on the drug release rate while the surfactant type, composition or density exerted only a minor effect.

Based on this, only the physical properties and the oil phase are the main factors affecting the drug release.

I do not want to be pessimistic, but in your case the only factor you can change to increase the drug release is the oil phase (viscosity of the oil phase) since the study will be conducted at constant temperature 37 C. For more on this topic, you may read the publication entitled "In vitro drug release mechanism from lipid nanocapsules (LNC) " contained in the following link:

https://www.researchgate.net/publication/41424264_In_vitro_drug_release_mechanism_from_lipid_nanocapsules_LNC

Hoping this will be helpful,

Rafik

Article In vitro drug release mechanism from lipid nanocapsules (LNC)

Dear Rafik karaman

Thanks for your answer.

In recent study, "drug release rates increased significantly with increasing the temperature from 4 to 50 degrees " but we can not change temperature.

Can we used surfactant such as tween 80 to decrease the affinty of drug to lipid?

Can we use surfactant such as tween 80 to decrease the affinty of drug to oil phase?

Can we use ethanol in release media to made sink condition? 

Best Regards

Dear Alieh,

Both factors that you mentioned might or might not affect the release of the drug. However, it is worth it to change the surfactant to tween 80. It might help increasing the release of the drug.

Rafik

Thank you for your kindness.

Dear Alieh Ameri, drug release rate from nanocapsules depends upon nature of capsule and shell. I think you are making lipid core-polymeric shell nanocapsules. In this case, you should ensure that capsule forming polymers is not acting as barrier to drug release. Two preliminary ways are to use water soluble poymer and to reduce thicknnes of shell both of which allow easy penetration/diffusion of water and drug molecule. Otherwise, you will be required to modify core materials. You should also note that oils (liquid) show faster drug release as compared to lipids (solid). You will get more help by sharing nature of core, shell and method of preparation.

Regards,

Mubashar

Tween 80 has high toxicity profile as our group checked before and If u decided to use T80 as an emulsifier Pls try to use it below 2 % in ur formulation n send final formulation with/without drug for MTT assay.... 

Dear Alieh, There are several factors can affect on the drug release such as type of surfactant, concentration of surfactant, bile salts, use of organic solvents, temperature, turbulence flow, type of lipids, etc.

Some of the lipid produces the high entrapment and slow release with respect to the increase in concentration of lipids whereas some of the lipid produces low entrapment with respect to the increase in concentration. Entrapment and drug release also depends upon the physico-chemical properties of drug. Hence, it is difficult to explain without knowing the properties of your drug. But, as per my opinion you can try with the type of surfactant and concentration of surfactant.

Lecithin is the one with which you can try.

Sometimes we prefer the lipid with HLB value and similarly we can use surfactant also with high HLB value. This can also enhance the solubility, drug release, small size of particles, but may affect on the entrapment efficacy.