Anionic Liposomes (Lyophosome™-PEGylated)
Description
Liposome formulations can be broadly divided into cationic, anionic and neutral subtypes. Charged liposomes are used in many different types of studies such as, blood complement studies, gene transfer studies and other biomedical applications to name a few. Cellsome® liposomes made from anionic PEGylated lipids provide certain benefits.
Anionic liposomes offer a number of attributes, relative to the challenges associated with cationic formulations such as, the administration of cationic liposomes results in higher cytotoxicity levels, both in vitro (Zhong et al., 2009) and in vivo (Balazs and Godbey, 2010). Anionic liposomes demonstrate greater stability in solution (Zhigaltsev et al., 2002, Phillips and Heydari, 1996), lead to lower aggregation when compared with neutrally charged liposomes, and have increased endocytosis when compared with cationic (Bajoria et al., 1997) and neutral liposomes.
To improve liposome stability and enhance their circulation times in the blood, a sterically-stabilized, hydrophilic polymer, polyethylene glycol (PEG), has been shown to be the optimal choice for obtaining sterically-stabilized liposomes. Using an Anionic Liposome with PEG will protect the liposomes from circulating proteins, improving their plasma clearance and enhancing their therapeutic effects.
The four products provided that are made from Anionic PEGylated Lipids provided here consist of either DSPC:Chol:DSPG:DSPE-PEG(2000) (60:30:5:5 molar ratio), DOPC:Chol:DOPG:DOPE-PEG(2000) (60:30:5:5 molar ratio), DSPC:Chol:DSPS:DSPE-PEG(2000) (60:30:5:5 molar ratio), or DOPC:Chol:DOPS:DOPE-PEG(2000) (60:30:5:5 molar ratio).
Lyophosome™ product catalog is composed of a large selection of freeze-dried liposomes with various types of lipids and wide range of zeta potentials and different properties. Lyophosome™ products should be used by scientists who understand liposome formulation and have the proper equipment to check the size, separate non-encapsulated drugs and do the proper assays. Freeze-dried liposomes cannot be used blindly.
Formulation Information
Anionic Liposomes (Lyophosome™-PEGylated)
For more information on the lipid composition of the liposomes mentioned above click here.
| Buffer, Lyoprotectant and Liposome Size | |
|---|---|
| Buffer | Deionized water* |
| Lyoprotectant | Trehalose |
| Liposome size | 100 nm (after hydration) |
| *If you prefer a different buffer please specify in your order. | |
Technical Notes
- Liposomes are formed upon hydration of the lyophilized formulation. If the lyophilized liposomes are hydrated with solution containing a water-soluble drug, then a large percentage of the drug will stay outside of the liposomes and in non-encapsulated form. It is advised to use a micro dialysis cassette or a spin column using the right-side beads (depending on the size of your drug) and separate the drug encapsulated liposomes from free drug and perform the drug assay in order to calculate the encapsulation efficiency.
- Lyophilized liposomes are mainly recommended to be used with drugs that have a short life in aqueous solution mainly due to hydrolysis. After adding the solution of the drug to lyophilized liposomes, the liposomes should be used immediately.
- Lyophosome™ products should be used by scientists who understand liposome formulation and have the proper equipment in order to check the size, separate the non-encapsulated drug and do the proper assays.
- Trehalose is used as a lyoprotectant in all freeze-dried liposome formulation. The size distribution after hydration of the freeze-dried formulation will be around 100 nm.
- Freeze-dried liposomes should be kept at -20°C.
Appearance
Lyophosome™ is a white lyophilized powder. Liposomes are formed upon adding water to the freeze-dried proliposomes and the appearance of the formulation will be white translucent liquid.
Ordering/Shipping Information
- All proliposome lyophilized formulations are shipped on dry ice at -78.5°C in insulated packages using overnight shipping or international express shipping.
- Lyophilized proliposomes should be frozen at -20°C. Upon adding water to proliposomes, liposomes are formed.
- 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
Lyophosome™ products should always be stored in a freezer at -20°C. Upon adding water to proliposomes, liposomes are formed.
Shelf Life
Lyophosome™ is made on order. The batch that is shipped is manufactured on the same day. It is advised to use the products within 12 months of the manufacturing date.
