Doxosome™ Kit-Doxorubicin Liposomes (Non-PEGylated)
Non-PEGylated doxorubicin liposome comes in a three-vial kit and has a lipid composition and liposome size similar to commercial Myocet®. Doxorubicin drug cannot be pre-loaded to the liposomes in the same way that is pre-loaded into the PEGylated liposomes. The matrix liposome in PEGylated liposome is hydrogenated soy PC which is a saturated lipid and creates a tight packed liposome suitable for pre-loading and holding the drug inside the liposomes. The matrix lipid in this formulation is L-⍺-phosphatidylcholine which is an unsaturated lipid. It makes a loose packed membrane and therefore, it cannot hold the drug for a long time. The doxorubicin drug should be loaded into the liposomes moments before use.
The kit comes in three vials. The first vial contains a very concentrated solution of liposomes. The liposomes are made in citrate buffer at pH 4. The second vial is composed of sodium carbonate at pH 11.4. Adding vial 2 to vial 1 makes a pH gradient around the lipid membrane. Due to the difference in the pH inside and outside of the liposomes, there will be a constant flux of proton from the inside to the outside of the liposomes. Due to this flux, doxorubicin molecules move in the opposite direction from the outside to the inside of the liposomes. During the remote loading process, due to pH gradient, the doxorubicin drug is able to freely pass into the liposomes where it is bound by hydrogen and nanocrystals of doxorubicin citrate salt to form larger doxorubicin compounds. As the new doxorubicin complexes are formed, they come together to form one of the three different shapes inside the liposomes. A long singular band that stretches the membrane, a closed circular band or an opened U-shaped band. The circular and U-shaped complexes are the most common ones. Doxorubicin liposomes that are formed by remote loading using pH gradient should be used immediately.
PEGylated formulation of doxorubicin liposomes is also available. For more information see here.
Doxosome™ Kit-Doxorubicin Liposomes (Non-PEGylated)
|3-Vial Kit for Doxosome™(Non-PEGylated)||Specification|
|Vial 1||Preformed liposomes composed of HSPC and cholesterol (55:45 molar ratio)|
|Vial 2||Sodium carbonate for making a pH gradient|
|Vial 3||Doxorubicin HCl in 0.9% saline|
|Instructions: Add 0.4 ml of the liposome (vial 1) to 0.6 ml of the sodium carbonate solution (vial 2). Then add 10 mg of the doxorubicin in 4 ml of the 0.9% saline solution (vial 3) to the mix, heat at 55-60°C for 7 min, and shake it for 10 s. The final concentration of doxorubicin in the liposomes is 2 mg/ml and the total volume of the reagent is 5 ml. Over 95% of the drug is loaded to the liposomes. The drug to lipid w/w ratio is 0.27:1.|
|Lipid Composition for Vial 1||Concentration (mg/ml)||Concentration (mM)||Molar Ratio Percentage|
|Total||100 mg/ml||166.8 mM||100|
|Buffer and Liposome Size for Vial 1||Specification|
|pH||4 (in 300 ml buffer)|
|Liposome Size||180 nm|
|Sodium Carbonate||166 mM|
|Doxorubicin HCl||Solution in 0.9% Saline|
Liposome Particle Calculator
Doxorubicin liposomes are unilamellar and sized to 100 nm. The molar concentration of liposome is 166.8 mM. By having liposome diameter (nm) and lipid concentration (µM), you can calculate the total number of the lipids in one liposome and the number of the liposomes in one milliliter of the liposome solution. To use the calculator click here.
Doxosome™ is a red translucent liquid made of nano size unilamellar liposomes. Usually, due to the small size of liposomes, no settling will occur in the bottom of the vial. The liposomes are packaged in an amber vial.
- All liposome based formulations are shipped on blue ice at 4°C in insulated packages using overnight shipping or international express shipping.
- Liposomes should NEVER be frozen. Ice crystals that form in the lipid membrane can rupture the membrane, change the size of the liposomes and cause the encapsulated drug to leak out. Liposomes in liquid form should always be kept in the refrigerator.
- Clients who order from outside of the United States of America are responsible for their government import taxes and customs paperwork. Encapsula NanoSciences is NOT responsible for importation fees to countries outside of the United States of America.
- We strongly encourage the clients in Japan, Korea, Taiwan and China to order via a distributor. Tough customs clearance regulations in these countries will cause delay in custom clearance of these perishable formulations if ordered directly through us. Distributors can easily clear the packages from customs. To see the list of the distributors click here.
- Clients ordering from universities and research institutes in Australia should keep in mind that the liposome formulations are made from synthetic material and the formulations do not require a “permit to import quarantine material”. Liposomes are NOT biological products.
- If you would like your institute’s FedEx or DHL account to be charged for shipping, then please provide the account number at the time of ordering.
- Encapsula NanoSciences has no control over delays due to inclement weather or customs clearance delays. You will receive a FedEx or DHL tracking number once your order is confirmed. Contact FedEx or DHL in advance and make sure that the paperwork for customs is done on time. All subsequent shipping inquiries should be directed to Federal Express or DHL.
Storage and Shelf Life
Doxosome™ products should always be stored at in the dark at 4°C, except when brought to room temperature for brief periods prior to animal dosing. DO NOT FREEZE. If the suspension is frozen, the encapsulated drug can be released from the liposomes thus limiting its effectiveness. In addition, the size of the liposomes will also change upon freezing and thawing.
Doxosome™ is made on daily basis. The batch that is shipped is manufactured on the same day. It is advised to use the products within 4 months of the manufacturing date.
References and background reading
5. Silva-López EI, Edens LE, Barden AO, Keller DJ, Brozik JA. Conditions for liposome adsorption and bilayer formation on BSA passivated solid supports. Chemistry and physics of lipids. 2014 Oct 31;183:91-9.