Novel Approaches for Brain Drug Delivery System-Review

International Journal of Pharma Research & Review, June 2013; 2(6):36-44 ISSN: 2278-6074In all of the studies it has been found thatsignificantly higher drug concentrations isdetected in the brain when the antitumordrug is encapsulated and delivered in aSLN. It is therefore a noteworthy findingthat SLNs appear by their nature to becapable of overcoming the BBB.Incomparison with surfactant coatedpolymeric NPs (specifically useful inbypassing BBB), SLN have also beenevaluated for brain delivery of the potentand frequently used HIV protease inhibitor(PI), atazanavir, that, like other PIs exhibitslow brain permeability [33].Polymeric Micelles and Microemulsions-Polymeric micelles as drug delivery systemsare formed by amphiphilic copolymershaving an A-B dib lock structure with A, thehydrophilic (shell) and B, the hydrophobic(core) polymers. The polymeric micelles arethermodynamically and kinetically stable inaqueous media.The size of polymeric micelles usuallyvaries from ca. 10 to 100 nm. This narrowsize range is similar to that of viruses andlipoproteins.The core is composed of hydrophobicpolymer blocks [e.g., poly (propyleneglycol) (PPG), poly (D, L-lactide), poly(caprolactone), etc.] and a shell ofhydrophilic polymer blocks (e.g., PEG). Mostof them are biodegradable andbiocompatible.Earlier studies have shown that poloxamer(PluronicTM) micelles conjugated withantibodies may improve brain distributionof haloperidol, a neuroleptic agent. Thisapproach resulted in a dramaticimprovement of drugefficacy. This resultindicates that Bio conjugates, Biomimeticpolymers provide an effective transport ofsolubilized neuroleptic agents across theBBB [34-36].Fig. 6: Schematic representation of the different Pharmaceutical carriers for drugpenetration across the BBB.DendrimersDendrimer is a highly branched polymermolecule formed by a central core to whichthe branches are attached, the shell of thebranches surrounding the core, and thesurface formed by the branches termini.They are of small size comparable to that ofpolymeric micelles or nanoparticles of smalldimensions. Thus, for instance, a typicaldendrimer molecule, such aspoly(amidoamine) (PAMAM) dendrimer,hasa diameter ranging from 1.5 to 14.5 nm.As carriers for drug delivery to the brain,dendrimers conjugates with anti-canceragents have been studied for the treatmentof tumors at CNS level. In addition, genedelivery into brain has been also shownSwatantra Bahadur Singh, IJPRR 2013; 2(6) 41