Carreadores nanoestruturados para veiculação de levofloxacino como potencial tratamento de infecções pulmonares

Author(s)

Viviane Lucia Beraldo de Araujo

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Ciências Farmacêuticas
• Defense date: 2023-05-23

Examining board members

Laura de Oliveira Nascimento; Taís Gratieri; Marlus Chorilli; Newton Andreo Filho

• Advisor: Laura de Oliveira Nascimento

Abstract

Lung infections, such as community-acquired pneumonia (CAP), are the leading cause of mortality and morbidity worldwide and can be caused by viruses, bacteria, or fungi. Bacterial CAP is usually treated with ?-lactam, macrolides, tetracycline, and/or fluoroquinolones antibiotics such as levofloxacin (LV). LV has a broad spectrum and is effective against CAP, but some rare adverse events such as tendinitis and risk of tendon rupture make its use cautious. Ideally, the treatment of CAP should not only target the etiological agent but also the exacerbated alveolar inflammation resulting from the disease. Therefore, the aim of this thesis was to develop nanostructured lipid carriers (NLCs) to deliver LV via pulmonary route, with the future intention of locally treating lung infections, potentially reducing the systemic concentration of LV and its adverse events. A pre-formulation study was conducted, including drug solubility in excipients and LV-excipient compatibility, characterized by thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction, and infrared spectroscopy. The formulation step involved determining and evaluating critical formulation and process parameters using multivariate analysis for formulation optimization, aiming for a stable system with high drug entrapment efficiency (EE). NPLLV_033 was the optimized formulation that achieved the desired characteristics (size < 200 nm, polydispersity ? 0.3, zeta potential around -20 mV, EE > 71%, and an acceptable level of LV degradation products (0.37-1.13%). However, the presence of LV impurities after NLC production led to the search for alternatives to reduce them, resulting in NLCs produced with other surfactants (NPLLV_034, with poloxamer 407, and NPLLV_035, with poloxamer 188), as surfactants play a crucial role as coating agents for nanoparticles, affecting their physicochemical and biological characteristics. The three NLCs exhibited similar physicochemical characteristics as described above, with NPLLV_034 and NPLLV_035 showing lower LV degradation. In the biological assays, the minimum inhibitory concentration (MIC) values of the three NLCs were similar and did not differ from free LV, indicating that the NLC-incorporated drug remained effective against the tested bacteria (Klebsiella pneumoniae and Staphylococcus aureus). The cell viability of Calu-3 (lung model) showed that NPLLV_034 did not reduced viability at 50 µg/mL.In the transwell system, with differentiated Calu-3 cells, NPLLV_034 was able to reduce the production of IL-8 after lipopolysaccharide stimulation compared to free LV, indicating a potential anti-inflammatory activity of the formulation. Haemolytic activity determination of the NLCs indicated different safe concentrations, in order of safety: NPLLV_034 > NPLLV_033 > NPLLV_035, making them considered safe for pulmonary administration. NPLLV_034 stood out in the physicochemical (greater drug stability) and biological assays, being the safest and least cytotoxic to Calu-3 cells, with the potential to reduce exacerbated inflammation, making it advantageous in the treatment of lung infections (AU)

• FAPESP's process: 18/03666-3 - Use of nanostructured carriers to load combined antibiotics
• Grantee: Viviane Lucia Beraldo de Araújo
• Support Opportunities: Scholarships in Brazil - Doctorate