Physicochemical Characterization of the Shell Composition of PBCA-Based Polymeric Microbubbles.

Area of Science:

• Biomaterials Science
• Nanotechnology
• Ultrasound Imaging

Background:

• Microbubbles (MB) are utilized as contrast agents in ultrasound (US) imaging.
• Polymeric MB are being explored for drug delivery due to their robust shells and high drug loading capacity.
• The shell composition of polymeric MB, crucial for drug delivery applications, is not well understood.

Purpose of the Study:

• To determine the molecular weight and polydispersity of poly(butyl cyanoacrylate) (PBCA) polymer chains forming the shell of MB.
• To assess the suitability of PBCA MB for drug delivery based on the physicochemical properties of their shell components.

Main Methods:

• Synthesis of PBCA MB with variations in preparation parameters (pH, surfactant, stirring speed, stirring time).
• Characterization of PBCA MB shell composition using gel permeation chromatography (GPC).

Main Results:

• The number average molecular weight (M n) of PBCA polymer chains in the MB shell was determined to be 4 kDa.
• Over 99% of the polymer chains in the PBCA MB shell were found to be below 40 kDa.
• These findings indicate that the polymeric building blocks are of a size conducive to renal excretion.

Conclusions:

• The characterized molecular weight and size distribution of PBCA MB shell components support their potential for safe and effective drug delivery.
• The small size of the polymer chains facilitates renal clearance, a desirable characteristic for intravenously administered drug carriers.
• This study provides critical physicochemical data on PBCA MB, advancing their development as drug delivery vehicles.