# Stabilization of Argan Oil Nanoemulsions Using Chitosan Extracted from Pink Shrimp Shells
## 1 Introduction  
Argan oil (_Argania spinosa_ L. [PERSON]) is a highly valued natural product in the fields of beauty and medicine due to its diverse therapeutic and cosmetic properties. Its rich composition of bioactive compounds, including unsaturated and saturated fatty acids, polyphenols, tocopherols, chlorophylls, carotenoids, phytosterosols, squalene, and coenzyme Q10, contributes to a wide range of benefits. These include improved skin hydration, enhanced elasticity, anti-aging effects, accelerated wound healing, and anti-inflammation properties, making it effective in treating skin conditions such as acne, psoriasis, eczema, and blisters [1, 2, 3, 4]. However, the stability and bioavailability of these bioactive compounds are often limited in conventional formulations, reducing their effectiveness. To overcomethese limitations, encapsulating organ oil in a dermatological nanoemulsion has emerged as a promising approach to enhance solubility, absorption, and the targeted delivery of active ingredients [2].  
Nanoemulsions are advanced colloidal systems characterized by nanometer-sized droplets and exist as either oil-in-water (O/W) or water-in-oil (W/O) dispersions. These formulations offer several advantages, including increased surface area, enhanced stability, and improved bioavailability of encapsulated compounds, making them highly suitable for drug delivery, food fortification, and cosmetics [5]. However, a major challenge in nanoemulsion technology is maintaining the long-term stability of nanoemulsions, as these systems are prone to Ostwald ripening and phase separation over time. A promising strategy to address this issue involves coating nanoemulsions with polymers such as chitosan, which can enhance both physical stability and functional properties.  
Chitosan (CS), a biopolymer derived from the deacetylation of chitin--a natural polysaccharide found in the exoskeletons of crustaceans and insects as well as the cell walls of certain fungi--possesses unique physicochemical properties. These include solubility in acidic solutions, biocompatibility, biodegradability, and functional versatility, making it widely applicable in pharmaceuticals, biotechnology, and food sciences [6; 7]. CS's ability to form thin films, emulsify substances, and exhibit antimicrobial activity makes it an ideal stabilizing agent for nanoemulsions [6]. Its amino groups interact with negatively charged molecules, creating steric and electrostatic barriers that prevent droplet coalescence [8]. Additionally, its intrinsic antimicrobial properties contribute to the extended shelf-life and safety of nanoemulsions across various applications. Despite its potential, there is still a need for research on optimizing CS-stabilized nanoemulsions, particularly in dermatological applications where formulation challenges remain.  
This study investigates the use of CS as a natural stabilizing agent for organ oil nanoemulsions. Specifically, it focuses on formulating stable nanoemulsions using a single nonionic surfactant and a low-energy emulsification method. Additionally, this research explores the enhancement of nanoemulsion stability through chitosan coating derived from pink shrimp waste. This approach not only improves the effectiveness of chitosan in nanoemulsion stabilization but also aligns with environmental sustainability by valorizing shrimp waste as a valuable resource in nanotechnology.