Nasal drops administration

R. J. Henry, N. Ruano, D. Casto, and R. H. Wolf. A pharmacokinetic study of midazolam in dogs Nasal drop vs. atomizer administration. Pediatr Dent 20 321-326 (1998). 

Figure 9.8 Deposition and clearance of nasal drops (upper panel 4 minutes after administration) and a nasal spray (lower panel 1 minute after administration) in a normal subject...

Figure 9.9 Illustration of correct and incorrect administration from a nasal drop-bottle...

The site of drug deposition in the nasal cavity highly depends on the method of administration. When administering solution formulation, it is important to consider the particle/droplet size. In addition, the limitation is that the entire dose must be given in a volume of 25-200 pL, depending on the formulation. Nasal drops are the simplest and most convenient form. However, the exact volume of dosing is difficult to determine, which may be a device-related matter, and rapid drainage from the nose is another problem with drops. 

Ease of administration by the patients, who are usually familiar with nasal drops and sprays... 

An alternative to the pulmonary route of administration is the nasal route, which is less demanding when it comes to formulation. With regard to, for example, particle size and simpler device development (5,90), examples are Minirin (Ferring), desmopression, and Suprecur (Sanofi-Aventis), buserelin, which are proteins formulated as nasal drops or nasal spray, where bioavailabdities of approximately 3% to 10% can be obtained. The formulations are just protein dissolved in purified water containing preservatives chlorbutanol and benzalkonium chloride (91,92). However, more advanced delivery systems are also used, for example, chitosan formulations where bioavailabihties of 14% to 15% compared to subcutaneous administration can be obtained (90). A recent review by nium (2007) gives more details on nanoparticulate systems used for nasal delivery (93) or consult Costantino et al. (2007) on the physiochemical and therapeutic aspects (5). 

The client should tilt the head back for the drops to reach the frontal sinus and tilt the head to the affected side to reach the ethmoid sinus. This action indicates the nurse knows the correct administration of nasal drops and does not need more teaching. 

The interaction between the MAOIs and oral phenylephrine is established, serious and potentially life-threatening. Phenylephrine commonly occurs in oral non-prescription cough, cold and influenza preparations, so patients should be strongly warned about them. Whether the effects of nasal drops and sprays and eye drops are also enhanced is uncertain, but it would be prudent to avoid them until they have been shown to be safe. The response to parenteral administration is also approximately doubled, so that a dosage reduction is necessary. 

Aqueous nasal drops as well as sprays are suitable for self administration. Viscous solutions are best avoided, as they make less contact with the nasal mucosa. To clear a congested nose the patient can also sniff a salt solution (half a teaspoon of salt in a glass of lukewarm water) four to six times a day. The benefit of the addition of sodium hydrogen carbonate for a so-called alkaline nasal wash has not been demonstrated [2]. 

The administration of nasal drops or sprays may sometimes cause temporary irritation of the nasal mucosa. Systemic (side) effects, e.g. of decongestants, may be seen as a result of absorption by the nasal mucosa and the gastrointestinal tract. Problems of this kind can be avoided, if the patient carefully follows the instructions for use, the quantity to be administered and the duration of the therapy. 

Nasal drops can be supplied in a multidose bottle with an integral dropper or with a dropper applicator. From a microbiological point of view an integral dropper may offer better protection, but for practical reasons a dropper applicator is often preferred. It makes dosing easier for the patient and so prevents overdosing (see Sect. 24.4.19.9). The disadvantage of a separate dropper for the administration of nasal drops is that mucus with bacteria from the nose can get into the liquid. This can be avoided if patients are instructed to keep squeezing the rubber balloon until the dropper tip has been removed from the nostril. In any case the dropper should be cleaned with warm water each time it has been used. 

Fig. 8.2 Position of the head during the administration of nasal drops. Source Recepteerkunde 2009, KNMP...

The administration of ephedrine may be given orally or topically as nasal drops or... 

Sedation and dry mouth are the most common adverse reactions seen with the use of TCAs. Tolerance to these effects develops with continued use. Orthostatic hypotension can occur with the administration of the TCAs. Orthostatic hypotension is a drop in blood pressure of 20 to 30 points when a person changes position, such as going from a lying position to a standing position. Mental confusion, lethargy, disorientation, rash, nausea, vomiting, constipation, urinary retention, visual disturbances, photosensitivity, and nasal congestion also may be seen. Sexual dysfunction may occur with administration of clomipramine. 

The implications of this for drag absorption are that administration of a drug as drops may only be suitable if the drag molecule is rapidly absorbed. Those drug molecules which diffuse across the nasal epithelium more slowly will need a longer contact time and may be better administered as sprays. The absorption rate of certain drags may be so slow that therapeutically active plasma levels are not attained. 

Usually, desmopressin is administered intranasally by use of sprays or drops. This administration route of desmopressin was considered to be more efficacious than the oral route, because bypassing the gastrointestinal tract increases the absolute bioavailability from less than 1% to approximately 5%. However, nasal application of desmopressin is accompanied by high intersubject and intrasubject variability in plasma pharmacokinetics [215]. Therefore, there have been several pharmaceutical research efforts to improve nasal delivery of desmopressin. 

Administration of more than one eye drop makes no sense. The second drop or a drop of double volume will be drained almost immediately. The availability could only be improved by lengthen the residence time of the preparation in the lower conjunctival sac. Closing the punctaby applying pressure with the thumb or fingers, but also closing the eyelids for approximately three minutes, increases the residence time and decreases the drainage of the ophthalmic solution to the nasal mucosae [48]. 

Even if eye drops are applied topically, undesirable systemic side effects could occur after absorption [43, 62]. The effects could be dangerous to life. Administration of scopolamine eye drops in children resulted in a toxic coma [63]. A substantial amount of active substance administered is drained through the nasolachrymal tube, reaches the nasal mucosae and will be absorbed in the systemic circulation. The correct instillation of eye drops reduces the risk of drainage to the nose but this cannot be completely eliminated. The correct methodology for instilUng eye drops will be discussed under Sect. 10.9. 

Non-viscous liquids can be sprayed into the nose as an alternative to drops. To aid this type of administration two types of containers are available squeeze spray bottles and nasal spray pumps (see Fig. 24.14). 

---