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Published on: June 12, 2021
Preparation, characterization, and antibacterial activity of tigecycline-loaded, ultrasound-activated microbubbles
Yanyan Xu1, Yajun Ren2, Yanyan Zhu1
1Department of Pharmacy, Lishui Hospital of Zhejiang University, Lishui, China.
Abstract:
Central nervous system infectious disease caused by the multidrug-resistant Acinetobacter baumannii (AB) seriously threatens human life in clinic. Tigecycline has good sensitivity in killing AB, but due to its wide tissue distribution and blood-brain barrier, concentration in cerebrospinal fluid is low, therefore, the clinical effect is limited. Herein, we designed micro-bubbled tigecycline, aimed to enhance its anti-MDRAB effects under ultrasound. The lipid microbubbles with different ratios of lipids to drugs (a ratio of 10:1, 20:1, and 40:1) were prepared by the mechanical shaking method. The morphology, zeta potential and particle size of microbubbles were tested to screen out the much better formulation. Encapsulation efficiency and drug loading amount were determined by ultracentrifugation combined with high-performance liquid chromatography. Then the in vitro antibacterial activity against AB was conducted using the selected ultrasound-activated microbubble. Results showed the selected microbubbles with high encapsulation efficiency and good stability. The mechanical shaking method is feasible for preparation of drug-loaded and ultrasound-activated lipid microbubbles. Using 0.2 mg/mL microbubbles, combined with 1 MHz, 2.5 W/cm2 and 1 min of ultrasound exhibited a potent anit-AB in vitro. This study indicates that tigecycline treatment in form of ultrasound-activated microbubble is a promising strategy against AB infections.
Insights
Ultrasound-activated microbubbles enhance tigecycline
Area of Science:
- Microbiology
- Nanotechnology
- Pharmacology
Background:
- Central nervous system infections caused by multidrug-resistant Acinetobacter baumannii (MDR-AB) pose a significant clinical threat.
- Tigecycline is effective against MDR-AB but has limited efficacy in cerebrospinal fluid due to low concentrations, hindering its use in CNS infections.
Purpose of the Study:
- To design and evaluate ultrasound-activated microbubbles loaded with tigecycline to enhance its antibacterial effects against MDR-AB.
- To optimize the formulation of lipid microbubbles for improved drug delivery and stability.
Main Methods:
- Lipid microbubbles with varying lipid-to-drug ratios were prepared using a mechanical shaking method.
- Microbubble characterization included morphology, zeta potential, and particle size analysis.
- Encapsulation efficiency and drug loading were quantified using ultracentrifugation and HPLC.
- In vitro antibacterial activity against MDR-AB was assessed using ultrasound-activated microbubbles.
Main Results:
- The optimized microbubble formulation demonstrated high encapsulation efficiency and good stability.
- The mechanical shaking method proved effective for preparing drug-loaded, ultrasound-activated microbubbles.
- Ultrasound-activated microbubbles (0.2 mg/mL) combined with specific ultrasound parameters (1 MHz, 2.5 W/cm², 1 min) showed potent in vitro antibacterial activity against MDR-AB.
Conclusions:
- Ultrasound-activated tigecycline-loaded microbubbles represent a promising strategy for combating MDR-AB infections.
- This approach enhances the delivery and efficacy of tigecycline, potentially overcoming limitations in treating CNS infections.
