Can a lidocaine 10% nasal spray be prepared? What excipients are necessary?

Introduction

This is a very high dosage and it should be noted at the dangers associated with lidocaine. Misuse of highly-dosed lidocaine creams have led to fatal accidents.

Nevertheless, the German formulary describes nasal preparations for use in     migraine and cluster headaches including a 4% solution of lidocaine HCl.

In the (experimental) treatment a distinction must be made between migraine and cluster headache: Cluster Headache: The instill of lidocaine nasal spray 4-10% is   described as a means of second   choice for acute treatment of cluster headaches (for stopping an attack). Although topical administration of topical anesthetics helps some patients, but not always,   each patient should try therapy, as systemic side effects are avoided in the course of efficacy. This is even more important because the attack frequency can be eight and more attacks per 24 hours.   The first choice medicines are still the parenteral 5-HT1B/D-agonists (Sumatriptan and Zolmitriptan) and the inhalation of oxygen.

Migraine:

The efficacy and use of lidocaine in migraine does not appear to have been scientifically proven, but it is mentioned in therapeutic studies. In the case of analogue dihydroergotamine applied the authors are unclear about the mechanism of action. Studies have apparently suggested a 4% solution of Lidocanehydrochloride   for local use, similar to Xylocain® 4% solution. In the current (AWMF) Migraine Guidelines   The treatment option with Lidocaine is not named. Dosage   The AWMF directive   does not provide information on the dosage and duration of administration of nasal sprays with   4-10% lidocaine in cluster headaches.

The German Migraine and Headache Society   recommends cluster headaches as therapy: "Nasal instillation of 1 ml of lidocaine solution 4-10% in the nostril along the side the occurrence of headache; In this case the head must be bent to the back below 45 ° and rotated at about 30-40 ° along to the affected side ".   This leads to a stopping of the attack at approximately 25-30% of the patients within the time span of a few minutes. In cases of migraine   the administered dose is 400 ul 4 percent lidocaine hydrochloride solution, possibly   500 ul, either in   one or both nostrils.

Contraindications Absolute or relative contraindications include: Significant disorders of the stimulation and conduction system, decompensated   heart failure,   cardiovascular disease,   advanced liver disease, pregnancy.

Specialties Lidocaine or Lidocasein hydrochloride (monohydrate) containing nasal droplets or nasal sprays are not registered.   So there is a need for a magistal preparation on prescription   a prescription is   desirable because this allows a good   Composition, which takes into account   the acidic reaction of lidocaine HCl and the possible incorrect preservation of the specimen

Magistal Preparations Little is known about the actual use of proposed   preparation. For aqueous preparations for use in the nose, Lidocais hydrochloride should be used   because the base is only about 0.4% soluble in water. Of the salt form of lidocaine is known to not penetrate   through intact skin  , but due to the lack of a barrier such as the cornea, a   locally numbing   effect can be expected in the case of use on mucous membranes. The proposed composition is hyptertoon. The ISO-osmotic concentration of lidocaine hydrochloride 4%. To the extent     a 4-procentige formulation would indeed be isotone, but it remains much too acidic (pH ~ 4.5) for the nasal mucosa. Therefore,   the pH is increased by alkaline sodium phosphate dodecahydrate, which results in a hypertonic preparation.

Composition

By adjusting the described 4% nasal spray   You can use the following formula: Lidocaine   HCl   1g  , Na2HPO4 400 mg; Benzalkonium Chloride 0.1% 1g   and water for injections AD 10 ml  

The final pH = 6.5

Administered   Quantity +/-  150 microliter

Shelf life   1 month