The drug is not metabolized in significant amounts; no interaction with the cytochrome P450 enzymes or P-glycoproteins has been found. Plasma half life is 3 to 5 hours. Plerixafor is excreted via the kidneys, with 70% of the drug being excreted within 24 hours. Chemistry
Plerixafor is a macrocyclic compound and a bicyclam derivative, the cyclam rings being linked at the amine nitrogen atoms by a 1,4-xylyl spacer. It is a base; all eight nitrogen atoms accept protons readily. The two macrocyclic rings form chelate complexes with bivalent metal ions, especially zinc, copper and nickel, as well as  cobalt and rhodium. The biologically active form of plerixafor is its zinc complex. Synthesis
Three of the four nitrogen atoms of the macrocycle cyclam... (1,4,8,11-tetraazacyclotetradecane) are protected with tosyl groups. The product is treated with 1,4-bis(brommethyl)benzene and potassium carbonate in acetonitrile. After cleaving of the tosyl groups with hydrobromic acid, plerixafor octahydrobromide is obtained. History
The molecule was first synthesised in 1987 to carry out basic studies on the redox chemistry of dimetallic coordination compounds. Then, it was serendipitously discovered by another chemist that such a molecule could have a potential use in the treatment of HIV because of its role in the blocking of CXCR4, a chemokine receptor which acts as a co-receptor for certain strains of HIV (along with the viruss main cellular receptor, CD4). Development of this indication was terminated because of lacking oral availability and cardiac disturbances. Further studies led to the new indication for cancer patients.
Whether these concerns occur in humans is unclear. Elderly
Biophysical studies using NMR spectroscopy has provided molecular details of how inhaled anesthetics interact with three amino acid residues (G29, A30 and I31) of amyloid beta peptide and induce aggregation. This area is important as "some of the commonly used inhaled anesthetics may cause brain damage that accelerates the onset of Alzheimers disease". Physical properties
It is administered as a racemic mixture of (R)- and (S)-optical isomers. Isoflurane has a melting point of 48 - 48.5°Celsius (118 - 119°Fahrenheit) and a boiling point of 48.5 - 49 °C (119 - 120 °F). It is non-combustible but can give off irritable and toxic fumes when exposed to flame. Mechanism of action
Similar to many general anesthetics, the exact mechanism of the action has not been clearly delineated. Isoflurane reduces pain sensitivity (analgesia) and relaxes muscles. Isoflurane likely binds to GABA, glutamate and glycine receptors, but has different effects on each receptor. Isoflurane acts as a positive allosteric modulator of the GABAA receptor in electrophysiology studies of neurons and recombinant receptors. It potentiates glycine receptor activity, which decreases motor function. It inhibits receptor activity in the NMDA glutamate receptor subtypes. Isoflurane inhibits conduction in activated potassium channels. Isoflurane also affects intracellular molecules. It inhibits plasma membrane calcium ATPases (PMCAs) which affects membrane fluidity by hindering the flow of Ca2+ (calcium ions) out across the membrane, this in turn affects neuron depolarization. It binds to the D subunit of ATP synthase and NADH dehydrogenase.