## 1 Introduction  
Azealic acid (HOOC(CH\({}_{2}\)))-COOH) is a saturated dicarboxylic acid naturally found in grains like rye, barley, and wheat. In addition, it is produced by the fungus _Malassezia furfur_, a yeast that lives on the normal skin of mammals. It has well-known effects, such as being ankiteratinizing, antibacterial, anti-inflammatory, being well-tolerated by most people with dermatological diseases, and it can be safely used for years. It prevents acne-causing bacteria from growing on the skin and keeps the pores clean, as it is able to kill bacteria such as _Propionibacterium_ acne and _Staphylococcus epidermidis_ by preventing them from producing cellular proteins. The pharmacological applications of azelaic acid (AA) include the treatment of inflammatory acne vulgaris with medium to moderate severity, skin pigmentation, and melasma [1; 2; 3; 4]. It was demonstrated that AA exerts a bacteriostatic effect on both aerobic and anaerobic bacteria including _Propionibacterium_[5]. Azelaic acid produces a direct anti-inflammatory effect due to its ability to neutralize free oxygen radicals, and hence, acne and rosacea-related inflammation can be treated with topical medication based on azealic acid applied to the skin [6]. The mechanism of action is based on the indirect activity against tyrosinase by inhibiting the interaction with thioredoxin reductase associated with the plasma membrane [7]. The traditional treatment of acne includes retinoids and retinoid-like drugs, benzoyl peroxide (BPO), antibiotics (clindamycin, erythromycincin, alone or combined with BPO), adapalene combined with BPO [8; 9; 10; 11], which are considered first-line treatments. It is well known that antibiotic overuse in the treatment of acne and other skin diseases has led to resistance patterns in _Pseudomonas acenes_, as both systemic and topical antibiotics are capable of changing the antibiotic-resistance patterns in bacteria [12]. Moreover, antibiotics used in the treatment of acne are also associated with the overgrowth of _Streptococcus pyogenes_ and _Staphylococcus aureus_ in the oral cavity, which in turn, may lead to the development of multiple pathologies [13]. In this context, azelaic acid, as a natural product, was proved to be effective in targeting multiple causes of acne, being well tolerated in numerous clinical trials [7] using different formulations (gel, cream, etc.) with an AA concentration in the range 10-20%. However, its limited aqueous solubility and inadequate penetration across the stratum corneum [14] might be related to different possible side effects such as itching and burning [15]. In order to overcome these limitations, researchers are focused on advanced and innovative formulations described as nanocarriers with versatile delivery systems for the effective management of acne and other cutaneous diseases [16]. Vesicular nanocarriers (liposomes, niosomes, ethosomes, cubosomes, etc.) and polymeric nanocarriers have been developed in order to increase its local efficacy while minimizing its side effects [17; 18; 19; 20; 21]. Among these, the advantages of the liposomal formulations are related to their unique composition, as cholesterol is able to reduce vesicle sizes in order to control skin permeation and deposition, along with significantly enhanced drug release [22]. The aim of our work was to elaborate a novel azelaic-acid-based liposomal formulation with enhanced biocompatibility, bio-availability, antimicrobial, antioxidant, antigenotoxic, and anti-inflammatory properties. For this purpose, the liposomes were formulated using the lipid film hydration technique and characterized in terms of physico-chemical and morphological features. The antibacterial effect of liposomal formulations was assessed in comparison to free azelaic acid against the most common Gram+ and Gram- germs. The cytotoxicity and viability assays were also performed for the liposomal formulations containing different concentrations of AA, using normal human dermal fibroblasts (NHDF).