Table 5.

Prominent Routes of Drug Administration for the treatment of neurological disorders.

S. No.	Route	Merits	Limitations
1.	Oral	Easy to administer	Irritation and nausea in some cases
		Easy absorption along the whole length of gastro-intestinal tract	First-pass effect
		Suitable for administration of high doses	Low drug stability due to effects of gastric juices
			Slow release of drug into the circulation
			Not suitable for drugs to be delivered to different brain regions
2.	Inhalation/Intranasal	Large surface area for absorption of drug into the circulation	Dose regulation and precision is not achieved easily
		Direct drug delivery into the circulation	Only suitable for administration of low molecular weight drugs
		Complete drug stability	Inconvenient for drug administration
		Bypass first-pass effect
		Bypass BBB, thus suitable for direct brain delivery of drugs
3.	Intravenous	Direct delivery of drug into the circulation	Risk of infection and vessel puncture
		Complete drug bioavailability in blood	Technical assistance required
		Complete drug stability	Inconvenient and comparatively unsafe
		No first-pass effect
		Suitable for drugs to treat various CNS disorders
4.	Rectal	Bypass first-pass effect	Irregular absorption
		Steady release of drug	Inconvenient
			Not suitable for drugs to treat several CNS disorders
			Slow absorption rate
5.	Intracerebral	Direct drug delivery to desired brain region	High technical expertise required
		Maximum drug availability in affected brain region	Unsuitable for regular drug administration
		Rapid drug release and effect	High risk of infection