###### Abstract  
Gold nanoparticles have been identified as a promising avenue for the development of drug carriers, particularly in the context of antimicrobial drug delivery, where limited solubility represents a significant challenge. The ability of gold nanoparticles to penetrate biofilms and disrupt fungal cell membranes makes them an effective tool to support antifungal therapy, especially against resistant strains. Gold nanoparticles also demonstrate synergistic effects with chemotherapeuticy and can influence the release profile of the active substances. This study aimed to develop a topical hydrogel drug formulation containing itraconazole (ITZ), with the addition of gold nanoparticles, to enhance its therapeutic properties. Due to ITZ's poor water solubility, three types of the gold nanoparticles (AuNPs) of different sizes were synthesized and subsequently coated with itraconazole. The resulting formulations were incorporated into carbopol gels and their ability to diffuse through semipermeable membranes was assessed. The findings demonstrated that the combination of gold nanoparticles and itraconazole elevated the diffusion coefficient to twice the level observed in gels without nanoparticles. Furthermore, the combined effect of gold nanoparticles and itraconazole against a reference _Candida albicans_ strain was investigated. The combination of gold nanoparticles and itraconazole demonstrated a growth-inhibitory effect on this strain, indicating that this formulation could potentially be employed in the treatment of fungal infections. The study confirms that hydrogels with itraconazole and gold nanoparticles can be obtained, offering enhanced drug diffusion. 202  
wide range of colors, such as brown, violet, blue, orange, and red, due to the interference of surface plasmons [5]. The main step in the synthesis of gold nanoparticles is the reduction of Au\({}^{3+}\) or Au\({}^{1+}\) to Au\({}^{\circ}\)[5; 6]. The most common method of their synthesis is the Turkevich method [7]. The most commonly used precursors for creating nanoparticles are tetrachloroauric(III) acid or gold(III) chloride. Some of the reducing agents used include hydrazine, glucose, sodium borohydride, formaldehyde, hydroxylamine, citric acid, oxalic acid, polyols, hydrogen peroxide, and even natural or bacterial substances. To prevent nanoparticles from clumping together, stabilizing agents such as trisodium citrate dihydrate, thiolate, polymers, and surfactants (especially cetyltrimethylammonium bromide CTAB) are used. The choice of synthesis method depends on the intended use of the synthesized nanoparticles and the desired particle size to be obtained [3; 6; 8; 9]. The Turkevich method represents a well-established approach to the synthesis of spherical AuNPs. The size and yield of the nanoparticles can be optimized by manipulating the reaction conditions, including pH, temperature, and the molar ratio of reagents. The utilization of elevated temperatures and the modification of reagent proportions can result in the formation of smaller, more spherical nanoparticles [10]. It is noteworthy that the concentration of the gold precursor and the presence of other metals, such as silver, can exert a marked influence on the morphology of the resulting nanomaterials. For example, the formation of nanostars in the final material may be induced [11]. The order of reagent addition can also influence the final characteristics of the nanoparticles in alterations to particle size and synthesis efficiency [10]. Surfactants, such as polyvinylpyrrolidone (PVP), are employed to stabilize the nanoparticles and regulate their growth, which can result in the formation of a range of shapes, including quasi-spherical, triangular, and nanoplatelet forms [12]. It is therefore evident that the method of synthesis is of paramount importance in obtaining the optimal size and shape of nanoparticles [13].