Retrometabolic drug design
Loteprednol etabonate was developed using retrometabolic drug design. It is a so-called soft drug, meaning its structure was designed so that it is predictably metabolised to inactive substances. These metabolites, Δ1-cortienic acid and its etabonate, are derivatives of cortienic acid, itself an inactive metabolite of hydrocortisone. Chemistry
Loteprednol etabonate is an ester of loteprednol with etabonate (ethyl carbonate). The pure chemical compound has a melting point between 220.5 °C (428.9 °F) and 223.5 °C (434.3 °F). Its solubility in water is 1:2,000,000, therefore it is formulated for ophthalmic use as either an ointment, a gel, or a suspension.Loteprednol is a corticosteroid. The ketone side chain of classical corticosteroids such as hydrocortisone is replaced by a cleavable ester, which accounts for the rapid inactivation. (This is not the same as the etabonate ester.) Chemical synthesis
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== Further reading ==
This inhibits the progression of the enzyme topoisomerase II, which relaxes supercoils in DNA for transcription. Daunorubicin stabilizes the topoisomerase II complex after it has broken the DNA chain for replication, preventing the DNA double helix from being resealed and thereby stopping the process of replication. On binding to DNA, daunomycin intercalates, with its daunosamine residue directed toward the minor groove. It has the highest preference for two adjacent G/C base pairs flanked on the 5 side by an A/T base pair. Crystallography shows that daunomycin induces a local unwinding angle of 8°, and other conformational disturbances of adjacent and second-neighbour base pairs. It can also induce histone eviction from chromatin upon intercalation. History
In the 1950s, an Italian research company, Farmitalia Research Laboratories, began an organized effort to isolate anticancer compounds from soil-based microbes. A soil sample was isolated from the area surrounding the Castel del Monte, a 13th-century castle in Apulia. A new strain of Streptomyces peucetius which produced a red pigment was isolated, and an antibiotic was produced from this bacterium that was found to have good activity against murine tumors. Since a group of French researchers discovered the same compound at about the same time, the two teams named the compound daunorubicin, combining the name Dauni, a pre-Roman tribe that occupied the area of Italy where the compound was isolated, with the French word for ruby, rubis, describing the color. Clinical trials began in the 1960s, and the drug saw success in treating acute leukemia and lymphoma.