Sumatriptan microspheres for Brain targeting through nasal route
Nasal delivery is a promising route for delivery of drugs which are susceptible to enzymatic, acidic and first pass effect; conventionally it has been restricted to treat local disease. Now a day, using nasal as an alternative route to oral delivery and injection for many of drugs to treat systemic disease. The possible drug transport mechanism to cross epithelial membrane in to systemic circulation is mainly passive diffusion; also some of drugs are transport by carrier mediate and pinocytosis. The interesting of nasal drug delivery belonging to the non invasive, self administration, patient friendly, high surface area of nasal cavity about 180 cm2, rapid onset of action and by pass the first pass effect it is useful for drugs unstable in GIT. Moreover, nasal route has great interest for targeting of drug to the brain, do you to its bypass brain blood barrier and less drug dose required and fewer systemic side effect appear especially for those drugs which have low blood concentration after routine delivery, the only exposed portion of CNS contact to the environment in the nasal cavity is olfactory region, it consist of 15% of the nasal surface area. Delivery from this route to the CNS takes place from olfactory region and trigeminal nerves within minutes, however, It has been shown that the quantity of drug transport from nasal to the brain are extremely low, normally less than 0.1 %, that is why no product is licensed via nasal rout for brain targeting. Drug carries like microspheres are used to improve drug absorption; they are spherical free flowing micro particles ranging in size 1 to 1000 µm, consisting of from natural or synthetic biodegradable polymers. The purpose of microsphere loading drug are to enhance residence time of the drug with in nasal cavity, increase drug absorption by opening the tight junction between cells, protect some of the drug from the enzymatic degradation with in nasal cavity.
The aim of this study was to prepare and systemically evaluate the effectiveness of mucoadhesive microspheres of sumatriptan.
Sumatriptan microspheres were prepared using carbapol 934p by emulsion cross linking method in which gultraldehyde used as a cross-linking agent.
The prepared microspheres were characterized in term of yield product, particle size study, morphology swelling index, entrapment efficiency, mucoadhesion and in vitro diffusion study.
The method of preparation were characterized by highly yield of production and the particle size of sumatriptan microspheres were prepared by emulsification cross linking method was 8 to 20 µm depending on polymer to drug ratio and this size range is suitable for deposition with in nasal cavity. Scanning electron microscopy showed that microspheres were spherical. While in vitro mucoadhesion study was found that increasing in polymer to drug ratio in vitro mucoadhesion also increased, because as the amount of the polymer increased might increases interaction between polymer and negatively charge ion of the silica acid residue in mucus.
In conclusion these results indicate that cabopole microspheres could be potentially applicable for delivery sumatriptan via nasal route to the brain for the treatment of migraine.