Open Access

ARTICLE

Characterization, In Vitro Dissolution, and Drug Release Kinetics in Hard Capsule Shells Made from Hydrolyzed κ-Carrageenan and Xanthan Gum

Tri Susanti^1,2, Syahnur Haqiqoh¹, Pratiwi Pudjiastuti^2,*, Siti Wafiroh^2,*, Esti Hendradi³, Oktavia Eka Puspita⁴, Nashriq Jailani⁵

1 Halal Research Center, Airlangga University, Surabaya, 60286, Indonesia
2 Departement of Chemistry, Faculty of Science dan Technology, Airlangga University, Surabaya, 60115, Indonesia
3 Department of Pharmaceutical Sciences, Faculty of Pharmacy, Airlangga University, Surabaya, 60115, Indonesia
4 Departement Pharmacy, Faculty of Medicine, Brawijaya University, Malang, 65145, Indonesia
5 Department of Bioprocess & Polymer Engineering, Faculty of Chemical & Energy Engineering, Universiti Teknologi Malaysia, 81310, Skudai, Johor, Malaysia

* Corresponding Authors: Pratiwi Pudjiastuti. Email: ; Siti Wafiroh. Email:

Journal of Renewable Materials 2025, 13(9), 1841-1857. https://doi.org/10.32604/jrm.2025.02024-0084

Received 31 December 2024; Accepted 22 May 2025; Issue published 22 September 2025

Abstract

This study aims to enhance the mechanical properties, disintegration, and dissolution rates of cross-linked carrageenan (CRG) capsule shells by shortening the long chains of CRG through a hydrolysis reaction with citric acid (CA). The hydrolysis of CRG was carried out using varying concentrations of CA, resulting in hydrolyzed CRG (HCRG). This was followed by cross-linking with xanthan gum (XG) and the addition of sorbitol (SOR) as a plasticizer. The results indicated that the optimal swelling capacity of HCRG-XG/SOR hard-shell capsules occurred at a CA concentration of 0.5%, achieving a maximum swelling rate of 445.39% after 15 min. Additionally, the best capsule hardness was also measured at this CA concentration, reaching a hardness level of 480.157 g (F = 4.67 N). FTIR analysis demonstrated that the presence of the acid group from CA altered the composition of the CRG chains. Furthermore, SEM-EDX mapping analysis revealed that the surface morphology of the synthesized capsules exhibited a relatively smooth texture with a limited number and size of pores, resulting in good capsule stability for drug delivery. The in vitro disintegration and dissolution rates of the HCRG-XG/SOR capsules were observed to be the fastest and highest at pH 1.2, respectively. The disintegration time was recorded at 20 min and 46 s, while the dissolution test indicated a drug release of 78.08% after 5 min and 100% after 120 min. The drug delivery kinetics of HCRG-XG/SOR followed the Ritger-Peppas model, indicating a complex release mechanism that involved swelling, diffusion, erosion, and capsule disintegration.

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