In particular, the formulation of rosuvastatin, molecule which is generally lipophilic, poses real problems owing mainly to their low solubility in aqueous liquid pharmaceutical excipients, to their propensity to precipitate or recrystallize in aqueous solution and to their low solubility in the fluids of the gastrointestinal tract from which they must be absorbed. The bioavailability of an active ingredient also depends on its concentration in the gastrointestinal fluid, said concentration itself being dependent on the release of the active ingredient. In particular, the more lipophilic an active ingredient is, the less tendency it has to migrate in gastrointestinal fluids. The above said problem can be overcome by nanoparticle drug delivery …show more content…
This enzyme acts as an escort for ubiquitin to its next destination E3 ligase enzyme. E2 ubiquitin conjugating enzyme Figure 16: Schematic representation of transfer of activated Ubiquitin from E1 activating enzyme to E2 conjugating enzyme The E3 enzyme act as a platform on which the target protein substrate and the active E2 ubiquitin complex can meet and interact. The E3 enzyme is extremely fussy about exactly which E2 enzyme and which protein can interact. The correct E2 enzymes loaded with activated ubiquitin could move in position itself correctly on the E3 ready for action. Skp 1 Target Protein Figure 17: Schematic representation of Target protein and ubiquitin conjugation in skp 1 Note: The Target Protein attached to the Skp 1 through F Box (Atrogin-1) which was not depicted in the figure. When both protein and ubiquitin uploaded onto the E3 enzyme they brought close enough together for the ubiquitin to be transferred to the target protein substrate either directly from the E2 or through short hop by