Introduction: Xylometazoline hydrochloride (HCl) is a nasal decongestant that causes vasoconstriction in the nasal submucosa. It has been used for more than 50 years for the treatment of nasal congestion caused by rhinitis/sinusitis. Iota-carrageenan is effective against a broad variety of respiratory viruses, which are the most common cause of infections of the upper respiratory tract. Therefore, it is used as the active component in the antiviral nasal spray Coldamaris prophylactic (1.2 mg/mL iota-carrageenan in 0.5% NaCl) and other medical device nasal sprays that are approved and marketed in the EU. Recently, we developed a nasal spray formulation containing both xylometazoline HCl (0.05%) and iota-carrageenan (0.12%) that provides decongestion and antiviral protection of the nasal mucosa at the same time.
Results: A set of in vitro experiments revealed that the vasoconstrictive properties of xylometazoline HCl and the antiviral effectiveness of iota-carrageenan against human rhinovirus (hRV) 1a, hRV8 and human coronavirus OC43 were maintained in the formulation containing these two compounds. Permeation experiments using bovine nasal mucosa showed that iota-carrageenan had no significant influence on the permeation of xylometazoline HCl. Finally, in the local tolerance and toxicity study, it was shown that the formulation was well tolerated at the application site with no occurrence of erythema or edema in the nostrils of all rabbits or any signs of toxicity in any of the organs and tissues inspected.
Conclusion: Investigations on compatibility of xylometazoline HCl and iota-carrageenan demonstrated that the substances do not influence each other, allowing both to fulfill their known specific clinical efficacy (xylometazoline HCl) and effectiveness (iota-carrageenan).
Keywords: antiviral; permeation; toxicity; vasoconstriction.