Desenvolvimento de hidrogéis com o argilomineral Laponita para liberação controlada de sulfadiazina de prata

Abstract

Cutaneous lesions represent a significant global public health issue due to their diverse etiologies and high risk of infection by microorganisms. Conventional treatment involves the use of products such as dermatological cream containing 1% silver sulfadiazine (AgSD), recognized for its antimicrobial activity. However, its low solubility and the need for frequent reapplications can cause discomfort, pain, and low treatment adherence. As an alternative, controlled release systems using clay-based nanocarriers have been investigated, with Laponite® (LAP) standing out — a synthetic phyllosilicate in the form of nanodiscs, capable of forming gels and entrapping substances between its layers. In this context, the present study aimed to develop LAP hydrogels for the controlled release of AgSD. A hydrogel containing 3.8% LAP was prepared, followed by the incorporation of AgSD to obtain hydrogels with 1 and 1.2% of the drug. Subsequently, the samples, along with a commercial cream containing 1% AgSD, were submitted to rheological, structural, thermal, and microbiological analyses. The addition of AgSD reduced the spreadability of the hydrogels, favoring skin adhesion and controlled release. Rheological analysis indicated that the hydrogel with 1% AgSD exhibited more balanced mechanical properties and greater conformity to irregular surfaces. Both hydrogels demonstrated superior thermal stability compared to the LAP hydrogel. Structurally, significant interactions between LAP and AgSD were evidenced, notably in the hydrogel with 1.2% AgSD, suggesting drug entrapment by the clay matrix. Release assays using Franz diffusion cells indicated controlled release profiles for both formulations, with emphasis on the hydrogel containing 1% AgSD, which maintained controlled release at the same concentration as the commercial cream. The hydrogels also exhibited significant antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli, in minimum inhibitory concentration, minimum bactericidal concentration, and antibiofilm assays, with a more balanced performance observed for the formulation with the lower concentration. Thus, the developed AgSD hydrogels demonstrated promising potential for future clinical application in cutaneous lesions, especially the formulation containing 1% AgSD, although additional studies are needed to validate their efficacy and safety in broader biological models.