Abstract
Background:
Bromelain (BRN), a naturally derived proteolytic enzyme, has gained significant attention for its anticancer potential. However, tumor heterogeneity and variability among patients necessitate personalized nanomedicine approaches. Nanoparticle size plays a critical role in enhancing tumor targeting through the enhanced permeability and retention (EPR) effect.

Objective:
The present study aimed to optimize the particle size of bromelain-loaded nanocarriers within the range of 50–100 nm using a Box–Behnken design to improve targeted delivery and therapeutic efficacy.

Materials and Methods:
Bromelain-loaded nanoparticles were prepared using the nanoprecipitation method. Three independent variables—PLGA concentration, Tween 80 concentration, and bromelain content—were selected based on preliminary screening and optimized using Design-Expert software. A Box–Behnken design comprising 17 experimental runs was employed to evaluate the effect of formulation variables on particle size and entrapment efficiency. The optimized formulation was further characterized for polydispersity index (PDI), zeta potential, surface morphology using scanning electron microscopy (SEM), drug content, and in vitro drug release.

Results:
The optimized formulation achieved a particle size of 78.64 ± 2.14 nm, falling within the desired range for enhanced tumor targeting. The formulation exhibited a high entrapment efficiency of 89.14% at 24 hours. The characterization studies confirmed uniform particle size distribution, appropriate surface charge, and spherical morphology. In vitro drug release studies demonstrated sustained release behavior, supporting its potential for improved therapeutic performance.

Conclusions:
The study successfully optimized bromelain-loaded nanocarriers with desirable particle size and high entrapment efficiency using a Box–Behnken design. The developed nanocarrier system shows promise for enhancing tumor targeting via the EPR effect and may serve as an effective platform for personalized cancer therapy.