Eexplain how different factors can influence the rate of drug diffusion in the nasal cavity?

- There are different factors that can influence the rate of drug diffusion in the nasal cavity, for example:

- Physico-Chemical Properties of the drug:  In terms of molecular weight, sometimes when is is administered via the nasal route in bigger quantities, the concentration of drug in the brain decreased. Molecular weights higher than 1000 Da show less ability to get absorbed in to the brain via the nasal mucosa.

- The degree of ionization of a drug administered via the nasal route, also affect the ability of drug to get absorbed in the nasal mucosa and its concentrations in the CSF.

- Drug Concentration, Dose and Volume of administration: they are factors that can affect nasal drug delivery to the brain.  When the concentration of the drug administered is high in volume, it can negatively impact the absorption of the drug regarding to local adverse effects and in some cases, it can damage the nasal mucosa.

-Presence of Enzymatic Activity: The nasal cavity has enzymes that form an enzyme barrier that affect the stability of the drug in the cavity, decreasing its therapeutic effects.