07-08-2012, 03:02 PM
HISTORICAL BACKGROUND
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MAGIC BULLETS
In 1900, Ehrlich (father of chemotherapy) described his famous side chain theory of antibody formation, proposing that antigens bind to pre-existing side chains on the cell surface, stimulating the synthesis of additional side chains that are then secreted into the extracellular fluid to neutralise the instigating antigen. He described these antibodies as “magic bullets” in search of toxins.
In 1910, Ehrlich achieved a breakthrough with compound 606. The yellow substance which Ehrlich called Salvarsan was an effective and reliable agent against Trypanosomes
DISCOVERY
Liposomes were first described by British haematologist Dr Alec D Bangham( father of liposome) in 1961 (published 1964), at the Babraham Institute, in Cambridge. They were discovered when Bangham and R. W. Horne were testing the institute's new electron microscope by adding negative stain to dry phospholipids. This was resemblance to the plasma lemma, and the microscope pictures served as the first real evidence for the cell membrane being a bilayer lipid structure.
He gave name to them firstly ‘Smectic mesophases ‘ which means layer lattices of alternating , closed bimolecular lipid sheets intercalated by aqueous spaces.
FIRST MARKETED PRODUCTS
The first liposomal oncology drugs approved for medical use in liposomal form are of the anthracyclines daunorubicin (DaunoXome; Nexstar Pharmaceuticals) and DOX [Doxil; Alza Corporation]. DaunoXome is formulated as a conventional liposmes whereas Doxil is an Stealth liposomal formulation
DIVISION INTO 3 DECADES
Genesis (1968-75)
The physiochemical characterization of liposomes had been carried out in this period. Moreover, thin lipid film hydration method had been developed to prepare multilamellar vesicles (MLVs). Liposomes were widely used to study the nature of biological membrane because of close resemblance of bilayered membrane with the biological membrane.