Biomedical Application of Polymers: A Case Study of Non-CNS Drugs Becoming CNS Acting Drugs.

BACKGROUND: The transport of CNS acting drugs across blood-brain barrier (BBB) is complex and guided by the molecular weight, pH, physicochemical and pathological state of the BBB among others.

METHODS: In view of this, literatures were assessed for possible conversion of Non-CNS to CNS acting drugs, whose ability to penetrate CNS can be improved using polymers for biomedical applications.

RESULTS: The findings have shown that compounds with pyridine, pyrrole, carboxamide, pyridone among others can be converted to CNS acting drugs that can be loaded in specialized carrier polymers for transportation across BBB. Such carriers are polymers, co-polymers, nanopolymers and polymeric miscelles that have amine around and pyridine as their hydrophobic site and carboxylic acid as their hydrophilic site. But balanced hydrophilic/hydrophobic site (amphiphilic) may not increase the transport rate of the carrier molecule.

CONCLUSION: Polymeric nanoparticles and copolymers can be used. Examples of such polymers are poly (lactic-co-glycolic acid), polylactic and poly (propyleneglycol, poly (DI)-lactide, polycaprolactone, and polyethylene glycol (hydrophilic). They are non-soluble, biodegradable, release the entrapped drug as they degrade via passive diffusion from polymeric core. Some of their degradation products can be converted to glycolic acid and lactic acid which are converted to carbon dioxide and water through the Kreb's cycle and finally eliminated via urination, perspiration, defecation and expiration.