# Alginate–Aluminosilicate Clay Beads for Sustained Release of Chlortetracycline Hydrochloride: Development and In Vitro Studies

## TL;DR

Researchers developed alginate-based beads with clay materials to control the release of an antibiotic, showing improved drug delivery and antibacterial effects.

## Contribution

The study introduces a novel composite bead system using halloysite nanotubes and kaolin for sustained antibiotic release.

## Key findings

- HNTs@Alg-1 beads showed the highest drug loading capacity at 59.85 ± 2.3 mg/g.
- Alginate inclusion extended drug release beyond 100 hours.
- CTC-loaded beads effectively inhibited E. coli and S. aureus.

## Abstract

This study reports the preparation of alginate (Alg) beads incorporating different amounts of halloysite nanotubes (HNTs) and kaolin (K) in the presence of Ca2+ ions to compare their drug loading and release behaviors. The resulting composites, HNTs@Alg and K@Alg, were characterized using FTIR, SEM–EDS, XRD, and XPS analyses. Chlortetracycline hydrochloride (CTC) was employed as a model antibiotic to evaluate their drug delivery performance. The concentration of Alg and the incorporation of HNTs or K markedly influenced the adsorption capacity and release profile. The maximum drug loading capacities were 48.12 ± 1.4 mg/g for HNTs, 40.1 ± 1.2 mg/g for K, 59.85 ± 2.3 mg/g for HNTs@Alg-1 (1 g HNTs and 1% Alg), and 68.74 ± 2.1 mg/g for K@Alg-1 (1 g K and 1% Alg). The inclusion of Alg enhanced sustained release, extending beyond 100 h. Among the composite beads, HNTs@Alg-1 showed superior CTC release behavior compared to K@Alg-1. Furthermore, antibacterial assays confirmed that the CTC-loaded beads effectively inhibited E. coli and S. aureus, demonstrating maintained drug activity after encapsulation. Both systems effectively prolonged CTC release and exhibited antibacterial efficacy, highlighting their potential as controlled drug delivery matrices for wound treatment applications.