Study of Effect of Lyophilization on The physicochemical stability of Liposome.

Lyophilization is promising approach to increase the shelf life of liposome. The major limitation in the widespread use of liposome is its instability. The aim of this study was to investigate the effect of lyophilization either in the presence or in the absence of lyoprotectant on liposome properties Lyophilization is used to ensure an increased shelf life of liposomes by preserving them in dry state more stable than the aqueous dispersion. When stored as aqueous system the encapsulated drugs are released & the liposome might aggregate or fuse. The process of lyophilization without cryoprotectant resulted in particle size increased & significant content leakage. This review work suggests that the investigation of stability of lyophilized liposomes containing PC (Phosphatidyl Choline) & cholesterol. Liposomes sphere-shaped vesicles consisting of one or more phospholipids bilayer in which both hydrophilic & hydrophobic drug entity can be incorporated. Due to their size & hydrophobic & hydrophilic character liposomes are promising for drug delivery. This structure turns liposomes into ideal drug carriers, since hydrophilic drugs tend to entrapped in the core; while hydrophobic ones will be entrapped within the lipid bilayers. Liposome is one of the most successful drug delivery system applying nanotechnology to potentiate the therapeutic efficacy & reduce toxicities of conventional medicines. The encapsulation efficiency partially depends upon the logP of drug. Lyophilization is a strategy often employed to improve liposomal formulation stability, due to reactivity being far less pronounced in the solid versus aqueous state.