I have collected 6h to 96h drug release data for unilamellar liposomal vesicle by using spectrophotometer. According to data, we have encapsulated chemotherapeutic agent in 80% efficiency. But when we look at the release profile, liposomes do release the drug at minimum level even at the 96h. Is it possible ? What are the reasons behind that ? Is minimum releasing okay ? What are the consequences of this thightly encapsulation ?
Hello,
The release profile of the encapsulated drug is strongly influenced by the characteristics of the release medium. For instance, low solubility of the target chemotherapeutic in the employed release medium might be the reason for your observations. Several other factors such as stability of the carrier and interactions between drug and carrier could also affect the release profile. Overall, all of these factors must be carefully considered in order to draw an accurate interpretation.
Furthermore, drug encapsulation efficiency and release profile are two independent factors and in some instances, one might not even be affected by the other, therefore, it is best not to use one of these factors for interpretation of the other one.
Hi, @Abouzar Karimi . First of all, I should thank you for your meaningful explanations. The one that you mentioned about not to compare encapsulation and releasing gave me another perspective (I have been expecting to see similar results between encapsulation and release - I was thinking that encapsulated drugs somehow will be released similarly as the percentage of encapsulation). I think I should add some parameters and compare them, such as composition of lipid, solubilities of chemotherapeutics, release media and so on. Also I am currently using centrifugal tubes with 10K filters to collect the data, maybe I should change my method or optimize it. Thank you for your contribution again. Sincerely.
Hi
Liposomes are vesicular systems, theoritically, the values are different from practical observations.
The loading efficiency is quite low in general.
It depends on the composition of the constituents like lipid ratio, process parameters like method followed, nature of the drug substance, solvent -drug solubility, drying rate, hydration of the vesicles etc.
As said by few, the release rate depends on the dissolution medium, Ph, etc. But whatever unless the drug is loaded inside the lamellae of vesicles, how can we expect drug release?
In your case, even after 96th hour the release rate is relatively low as you said, that may be because the drug loaded is very low or not loaded, drug solubility is not matching with the dissolution medium.
In some cases the drug might be degraded which might be in active or inactive forms which maynot be identified by the spectoscopic methods what you have followed. As the name of the drug is not disclosed, i am able to give information in general.
Dear Sir,
You need to see the Biopharmaceutical Classification of Drugs first but still you can modify the release pattern by the Liposome approach.
Thanks
Dear researcher,
There are various reasons which could be affected the final release of the drug:
1- The drug loading value in your encapsulated nano-system is high in its capacity; it is better to recheck its loading efficiency again. Liposomal nano-compartments have not usually very high drug loading capacity.
2- There is no direct relationship between high drug loading capacity and a high level of drug release since a wide variety of subjects such as the interaction between nano-liposome and drug, type of release medium, decomposition of drug and lack of detection through spectroscopies, etc. can potentially affect nano-compartment drug release.
3- You can also use HPLC spectroscopy for the detection of release amounts instead of UV-vis.
Dear Researchers, Asghar Narmani , Susanta Paul , Raja Rajeswari Kamisetti . Thank you for your attentions and also your contributions to my question. It was very helpful in the context of optimizing my experiments. Sincerely.
Merhaba Furkan,
It is a matter of "sustained release" or "burst release" ...
In fact, that is a beauty of liposomes; i.e. they can be engineered to meet different applications.
The question is: "Do you want your drug to be released fast (in a short span of time) or slowly (sustained release / depot effect)?
Nevertheless, your encapsulation efficiency of 80% is excellent.
Merhaba Dr. M. R. Mozafari ,
We are currently studying with chemotherapy regimen which has 4 different drugs. And each of these drugs have high toxicity levels and high doses of these drugs given to patients. So we want to prevent high toxicity, release as controlled manner, obtain maximum blood circulation and target the tumor. So overall, we want our drugs to be released slowly.
In addition, thank you for your comment. Our experiments still continuing, we hope to see promising results. 80% encapsulation has not optimized yet. I hope we will show this data as statistically significant.
Also I am amused to study with liposomes, they are versatile as you said. And I figured out their beauty as an undergraduate student, still continuing.
Sincerely
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