Fabrication of polymethyl methacrylate microspheres for improving immunogenicity of tetanus toxoid

Background and objectives

The polymer’s slow hydrolysis facilitates the sustained release of the immunogen, stabilizing the antigen encapsulated within the microspheres. As a result, microspheres ranging from 40 µm to 70 µm in diameter can be formed. This innovative microsphere formulation allows for efficient uptake by macrophages and other antigen-presenting cells. This study aimed to use biocompatible polymethyl methacrylate microspheres for the controlled delivery of antigens.

Methods

The potency of various formulations containing encapsulated tetanus toxoid (TT) with polymethyl methacrylate polymer microspheres was assessed using the toxin neutralization and challenge methods. The neutralization test was conducted on pooled sera two weeks after the initial immunization and weekly for four weeks following the booster dose administration. Scanning electron micrographs of the microspheres revealed drug leaching from spherical granular matrices.

Results

The injection site showed a higher distribution of smaller microparticles, resulting in depot release. The polymer coating’s thickness was significantly lower compared to the 25% polymer microspheres. Concentrations ranging from 0.00024 mL to 0.00030 mL caused significant tetanic paralysis. Two weeks after the initial immunization, the antigenic activity of TT was below the minimum threshold, possibly due to insufficient levels of antigenic TT within the system within seven days post-immunization. The polymethacrylate microsphere elicited a notable immune response, but only the polymer concentration of 25% w/v met the I.P. requirements; lower polymer concentrations were ineffective.

Conclusions

The polymer’s slow hydrolysis facilitates the sustained release of the immunogen, stabilizing the antigen encapsulated within microspheres. Consequently, microspheres ranging from 40 µm to 70 µm in diameter can be assembled. This innovative microsphere formulation allows for efficient uptake by macrophages and other antigen-presenting cells.

Full text

https://www.xiahepublishing.com/2572-5505/JERP-2023-00005

The study was recently published in the Journal of Exploratory Research in Pharmacology.

Journal of Exploratory Research in Pharmacology (JERP) publishes original innovative exploratory research articles, state-of-the-art reviews, editorials, short communications that focus on novel findings and the most recent advances in basic and clinical pharmacology, covering topics from drug research, drug development, clinical trials and application.

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