Non-PEGylated DOTA Liposomes for Remote Loading Radioactive Divalent Cations
Description
DOTA encapsulated liposomes are used for remote loading of radioactive divalent ions such as radioactive copper into the liposomes. Cationic ions will not pass through the membrane if there is no pH gradient. Divalent ion will cross the liposome membrane only when there is a flux of proton across of 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 inside of the liposomes to outside of the liposomes. Due to this flux, divalent cations move in the opposite direction from outside to inside of liposomes. Liposomes are thermodynamically stable structures and not very permeable to divalent cations after they are formed. If there is no pH gradient, the divalent cations cannot move from outside to inside of the liposomes, where they will remain outside and won’t cross the membrane. The driving force for remote loading in proton gradient.
The radioactive divalent copper is externally added to the liposomes. The divalent ion passes the membrane using pH gradient method and chelates DOTA.
Formulation Information
Non-PEGylated DOTA Liposomes for Remote Loading Radioactive Divalent Cations
| Lipid Composition | Concentration (mg/ml) | Concentration (mM) | Molar Ratio Percentage |
|---|---|---|---|
| 1,2-distearoyl-sn-glycero-3-phosphocholine | 11.32 | 14.4 | 60 |
| Cholesterol | 3.71 | 9.6 | 40 |
| Total | 15.03 mg/ml | 24 mM | 100 |
| Buffer, Liposome Size and Encapsulated DOTA | Specification |
|---|---|
| Buffer | HEPES Buffered Saline |
| pH | 4 |
| Liposome size | 100 nm |
| 1,4,7,10-Tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) | 10 mM |
| Vial 2 | Specification |
|---|---|
| Sodium Carbonate | 166 mM |
| pH | 11.4 |
Technical Notes
- Liposomes are unilamellar and sized to 100 nm. If you need them to be made in another size, then you should mention that at the time of ordering. Unilamellar liposomes can be made in 50 nm and 200 nm sizes. Liposomes that are larger than 200 nm are multilamellar structure.
- Liposomes are made in PBS buffer at pH 7.4 but it can be made in any other buffer of your choice. You can specify your buffer at the time of ordering.
- Liposomes are made in degassed buffer that is purged with argon to avoid oxidation of the unsaturated phospholipids.
- Liposomes are made under sterile condition.
- Liposomes are unilamellar and therefore due to their small size they will not settle in the bottom of the vial.
- If you need to take multiple aliquots out of the vial, for use over a period of time, then it is advised to take extreme care in not contaminating the vial. It is recommended to handle the vial under a sterile hood to maintain the sterility of the product.
- Liposomes should never be frozen. Ice crystals that form during freezing will rupture the lipid membrane of the liposomes and change the size the liposomes particles.
- Liposomes should be kept in refrigerator at 4°C in order to avoid the hydrolysis of the liposomes.
- Liposomes should be kept at 4°C and NEVER be frozen.
Appearance
DOTA liposome is a white 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.
Ordering/Shipping Information
- 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 and change the size of the liposomes. 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
Storage
DOTA liposome 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.
Shelf Life
DOTA liposomes are 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.
