## 1 Introduction  
One of the most important physiological defense mechanisms is the integrity of the nasal mucosa. Nasal secretions primarily derive from anterior serous glands, goblet cells, sinus secretions, and small semiconcus glands. The passage of water into the nasal lumen is facilitated by a network of subepithelial capillaries [1; 2]. For a variety of reasons, this delicate balance can be disrupted, leading to nasal dryness by compromising both the epithelial barrier and mucociliary transport [3].  
The most common symptoms range from mild burning, itching, and nasal congestion to a reduced sense of smell, persistent nasal discharge, and visible scabs on the nose. Dry rhinitis is one of the various forms of non-allergic rhinitis where the symptoms are independent of any allergic or infectious factors. Depending on the underlying disease, this condition may be nasal only or may be associated with other symptoms such as dry mouth [4; 5; 6]. Other causes of nasal dryness include climatic factors, workplace conditions, advancing age, allergic rhinitis (house dust mites and molds), bacterial infections, obstructive sleep apnea (OSA), or even specific side effects of medications. Of course, one of the first symptoms of a cold infection is the so-called \"runny nose\" [7; 8; 9].  
Maintaining the nasal mucosa with continuous topical application of nasal sprays maintains good humidification and hydration and is an important therapy to counteract dry nose symptoms. Saline nasal sprays are commonly used, and there are several supposedly superior formulations on the market, such as those containing hyaluronic acid (HA), N-acetylcysteine (NAC), and Methylsulfonylmethane (MSM).  
Hyaluronic acid is a physiological component of the nasal mucosa and belongs to the class of bioadhesive polymers. It increases the bioavailability and absorption of some compounds due to its high viscosity and mucoadhesiveness. One of its main functions is to moisturize the surface of the nasal pits to restore normal hydration [10; 11; 12]. It also intervenes in the regulation of vasomotor tone and glandular secretion, contributing to the defense of the nasal mucosa [13].  
The mucolytic action of N-acetylcysteine is attributed to its ability to cleave the disulfide bridges that characterize many mucoproteins, which, once the bonds are broken, disintegrate into smaller units of lower viscosity, allowing excess mucosal mass to be thinned and facilitating subsequent expulsion. Some studies suggest that NAC stimulates glutathione biosynthesis by neutralizing free radicals and acting as an antioxidant [14; 15]. In other studies, NAC has been found to have anti-inflammatory activity through the inhibition of nuclear factor NF-kB and modulation of pro-inflammatory cytokine synthesis [16; 17].  
Methylsulfonylmethane (MSM) is an organosulfur compound found naturally that has gained recognition in the realm of complementary and alternative medicine [18]. Over the years, several studies have highlighted that MSM has many effects (antioxidant and anti-inflammatory effects, anticholinesterase activity, and the capacity to induce histamine release from mast cells) [19] that allow it to cover a wide range of applications ranging from stress reduction, pain alleviation, and the treatment of parasitic infections, to claims of energy enhancement, metabolism acceleration, circulation improvement, and wound-healing promotion [20; 21; 22; 23; 24; 25].  
The purpose of this article is to investigate the efficacy and safety of VIARINOX(r), a new patented technology suitable for the treatment of otolaryngological disorders. The efficacy of VIARINOX(r) is due to the main components present in the formulation: sodium hyaluronate, methylsulfonylmethane (MSM), and N-acetylcysteine. The innovation of the technology under study is the presence of the three active ingredients in a single formulation, which gives it the ability to protect the nasal mucosa and to exert antioxidant and anti-inflammatory effects at the same time.