Nasal delivery

Colombo, P. (1999), Mucosal drug delivery, nasal, in Mathiowitz, E., Ed., Encyclopedia of Controlled Drug Delivery, J Wiley, New York, pp. 593-605. 

During oral drag absorption, metabolism can occur in the enterocyte cells that line the lumen of the intestine and in the liver before a drug enters the systemic circulation. Loss of drug in either of those locations constitutes first pass elimination . This first-pass effect can be observed for any type of extravascular delivery (nasal, pulmonary, rectal, vaginal, etc.). The magnitude of the first-pass elimination can be quite different in different tissues. However, the most common site for first-pass metabolism is the gut and liver. Once a drug enters the systemic circulation, most of its metabolic elimination occurs in the liver. Consequently, much of the literature on metabolism centers on hepatic metabolism. 

Drug Delivery Mucoadhesive Hydrogels, p. 1169. Drug Delivery Nasal Route, p. 1201. 

Desmopressin may be given orally, intranasally, SC, or IV. The oral dose must be determined for each individual patient and adjusted according to the patient s response to therapy. When the drug is administered nasally, a nasal tube is used for administration. The nasal tube delivery system comes with a flexible calibrated plastic tube called a rhinyle. The solution is drawn into the rhinyle. One end is inserted into the nostril and the patient (if condition allows) blows the other end to deposit solution deep into the nasal cavity. A nasal spray pump may also be used. Most adults require 0.2 mL daily in two divided doses to control diabetes insipidus. The drug may also be administered via the SC route or direct IV injection. 

Educating the Patient and Family If lypressin or desmopressin is to be used in the form of a nasal spray or is to be instilled intranasally usingthe nasal tube delivery system, the nurse demonstrates the technique of instillation (see Fhtient and Family Teaching Checklist Self-Adnrinistering Nasal Vasopressin). The nurse includes illustrated patient instructions with the drug and reviews them with the patient. If possible, the nurse lias the patient demonstrate the technique of administration. The nurse should discuss the need to take the drug only as directed by the primary health care provider. The patient should not increase the dosage (ie, the number or frequency of sprays) unless advised to do so by the primary health care provider. 

When administering nasally, a nasal tube is used for administration. The nasal tube delivery system comes with a flexible calibrated plastic tube called a rhinyle... 

Hamman et al. [281,282] tested five trimethyl chitosans with different degrees of quaternization as nasal delivery systems the degree of quaternization had a major role in the absorption enhancement of this polymer across the nasal epithelia in a neutral environment. 

Water-soluble polymers can also be used as aqueous solutions for drug delivery. Although the polymer is already dissolved, its increase in viscosity of the drug solution causes the drug to be retained somewhat longer in the desired application. This technique is common with ocular, nasal, and oral applications of drug solutions. 

A number of other peptide molecules are currently being explored for delivery via inhalation (6). Very recently, a much smaller peptide (leuprolide, about 9 amino acid residues) has been delivered by metered dose inhaler (MDI) in a characterized fashion to humans (7). This work revealed that about 50% of a dose deposited in the lung could be bioavailable. This value is much greater than those reported for nasal bioavailabilities of this and similar molecules (8). These results, and ours in the rat lung (9), imply that inhalation administration of some peptide and polypeptide molecules is perfectly feasible. 

Possible noninvasive routes for delivery of proteins include nasal, buccal, rectal, vaginal, transdermal, ocular, oral, and pulmonary. For each route of delivery there are two potential barriers to absorption permeability and enzymatic barriers. All of the... 

Nasal Systemic Drug Delivery, Yie W. Chien, Kenneth S. E. Su, and Shyi-Feu Chang... 

Virtually all therapeutic proteins must enter the blood in order to promote a therapeutic effect. Such products must usually be administered parenterally. However, research continues on the development of non-parenteral routes which may prove more convenient, less costly and obtain improved patient compliance. Alternative potential delivery routes include transdermal, nasal, oral and bucal approaches, although most progress to date has been recorded with pulmonary-based delivery systems (Chapter 4). An inhaled insulin product ( Exubera , Chapters 4 and 11) was approved in 2006 for the treatment of type I and II diabetes. 

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