A Review on In Vitro Methods and Factors Affecting Nasal Drug Absorption

Nasal drug delivery is an excellent approach for avoiding first pass effect of oral dosage form. It offers a direct systemic delivery of drugs. Nasal administration can therefore be used as an alternative to oral administration for example tablets and capsules if a fast effect is desired or if the drug is extensively degraded in the gut or liver. The primary goal of this article is to study factors affecting nasal drug absorption and the in-vitro methods available for nasal absorption of drugs. There are many in-vitro models for testing absorption studies and it has many advantages over in-vivo methods such as a controlled environmental study of epithelial cell growth and differentiation, drug transport pathways and mechanisms are elucidated easily, it has very fast means of evaluating drug permeability and to minimize expensive use of animals. Cell culture and cell line models were found to be best for nasal in-vitro absorption studies. Similar results are obtained from in-vitro studies. So by using in-vitro methods one can mimic the in-vivo conditions. It avoids disadvantages of in-vivo study. It was concluded that in-vitro models mimics the results of in-vivo study. But up till now no any system is superior to one another. Keywords- In-vitro methods, nasal drug absorption, PDMS and Culture models.