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Lipid microsphere formulation containing rifampicin targets alveolar macrophages
1Institute of Medical Science, St. Marianna University School of Medicine, Kawasaki, Japan. m2take@marianna-u.ac.jp
Abstract:
The study demonstrated that lipid microspheres (LM) containing rifampicin (LM-RFP) could deliver the drug to alveolar macrophages in vitro and in vivo, and that intranasal administration to animals could achieve preferential accumulation in the lungs with less effect on the liver. The LM-RFP particles had a mean diameter of 247.2 +/- 75.7 nm, and their size remained stable when stored at 4 degrees C or 25 degrees C for at least 4 weeks. In vitro uptake of [(3)H]LM-RFP by alveolar macrophages was over 4 times higher than that of unencapsulated [(3)H]RFP, whereas the in vivo uptake was 30 times higher. Flow cytometric analysis and confocal laser scanning microscopy confirmed that LM could deliver the encapsulated drug effectively to alveolar macrophages in vitro and in vivo. Intranasal administration of [(3)H]LM-RFP to normal mice resulted in preferential pulmonary uptake of the drug and lower levels in the blood and liver compared with administration of unencapsulated [(3)H]RFP. In conclusion, LM-RFP could be a promising preparation for delivery via the respiratory tract to tuberculosis (TB) and TB/HIV patients.
Insights
Lipid microspheres (LM) carrying rifampicin (LM-RFP) effectively deliver drugs to lung macrophages. Intranasal administration shows preferential lung accumulation, offering a promising delivery method for tuberculosis patients.
Area of Science:
- Pharmacology
- Nanotechnology
- Respiratory Medicine
Background:
- Tuberculosis (TB) treatment requires effective drug delivery to alveolar macrophages.
- Current drug delivery methods may have limitations in targeting lung tissues and minimizing systemic side effects.
Purpose of the Study:
- To evaluate lipid microspheres (LM) containing rifampicin (LM-RFP) as a novel drug delivery system.
- To assess the in vitro and in vivo efficacy of LM-RFP for targeting alveolar macrophages.
- To investigate the biodistribution of intranasally administered LM-RFP.
Main Methods:
- Characterization of LM-RFP particle size and stability.
- In vitro uptake studies of LM-RFP by alveolar macrophages using radiolabeled drug.
- In vivo biodistribution studies following intranasal administration in mice.
- Flow cytometry and confocal laser scanning microscopy for cellular uptake confirmation.
Main Results:
- LM-RFP particles exhibited a stable mean diameter of approximately 247 nm.
- In vitro and in vivo uptake of LM-RFP by alveolar macrophages was significantly higher (4x and 30x, respectively) than unencapsulated rifampicin.
- Intranasal administration of LM-RFP led to preferential lung accumulation and reduced liver exposure compared to free rifampicin.
Conclusions:
- Lipid microspheres are effective carriers for rifampicin delivery to alveolar macrophages.
- Intranasal administration of LM-RFP facilitates targeted lung delivery, reducing systemic exposure.
- LM-RFP represents a promising formulation for respiratory tract delivery in tuberculosis and TB/HIV patients.
