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Spray-Dried Inhalable Favipiravir Dry Powder Formulation for Influenza Therapy: Preparation and In vivo Evaluation
Xinyu Zhang1,2, Baogang Wang2, Likun Xu2
1School of Public Health and Health Management, Gannan Medical University, Ganzhou 341000, People's Republic of China.
Background:
Influenza, a seasonal infectious disease, has consistently posed a formidable challenge to global health in recent years. Favipiravir, an RNA-dependent RNA polymerase inhibitor, serves as an anti-influenza medication, currently administered solely in oral form for clinical use. However, achieving an effective therapeutic outcome often necessitates high oral doses, which can be accompanied by adverse effects and suboptimal patient adherence.
Objective:
To enhance favipiravir delivery efficiency and potentially mitigate dosage-related side effects, this study aimed to formulate favipiravir as a dry powder for pulmonary inhalation, facilitating direct targeting of lung tissue.
Methods:
Employing L-leucine as a carrier, favipiravir was prepared as an inhalable dry powder through the spray-drying technique. A 3x3 full-factorial design approach was adopted to optimize the formulation. The optimized spray-dried powder underwent comprehensive characterization, including assessments of its morphology, crystallinity, flowability, and aerodynamic particle size distribution. The therapeutic efficacy of the powder was evaluated in a mouse model infected with the H1N1 influenza virus.
Results:
The formulated powder demonstrated good aerosol properties, rendering it suitable for inhalation delivery. Its therapeutic efficacy was demonstrated in the mouse model, where it exhibited marked protective effects against the virus in vivo after 5 days of treatment. Notably, the inhalation dose required (15 mg/kg/day) was significantly lower than the oral gavage dose (150 mg/kg/day), indicating that substantially reduced doses, when administered via inhalation, were sufficient to confer protection against mortality in mice.
Conclusion:
The findings underscore the potential of inhalation therapy using spray-dried favipiravir powder as an effective and efficient treatment option for influenza, offering the promise of reduced dosing requirements and associated adverse effects.
Insights
Inhaled favipiravir powder offers an effective influenza treatment. This study shows lower doses via inhalation provide protection against H1N1 influenza in mice, reducing side effects.
Area of Science:
- Pharmaceutical Sciences
- Infectious Diseases
- Drug Delivery Systems
Background:
- Influenza remains a significant global health challenge, often requiring high oral doses of favipiravir.
- Current oral favipiravir administration can lead to adverse effects and poor patient adherence.
Purpose of the Study:
- To develop an inhaled dry powder formulation of favipiravir for direct lung delivery.
- To improve favipiravir delivery efficiency and reduce dosage-related side effects.
Main Methods:
- Favipiravir was formulated into an inhalable dry powder using L-leucine and spray-drying.
- A 3x3 full-factorial design optimized the formulation.
- Characterization included morphology, crystallinity, flowability, and aerodynamic particle size distribution.
- Efficacy was tested in a mouse model infected with H1N1 influenza.
Main Results:
- The spray-dried powder exhibited suitable aerosol properties for inhalation.
- Inhaled favipiravir demonstrated significant protective effects against H1N1 influenza in vivo.
- The effective inhalation dose (15 mg/kg/day) was 10-fold lower than the oral dose (150 mg/kg/day).
Conclusions:
- Inhalation therapy with spray-dried favipiravir powder is a promising strategy for influenza treatment.
- This approach offers potential for reduced dosing and fewer adverse effects.
- Pulmonary delivery enhances favipiravir's therapeutic efficiency.
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