Author: H.N. Imtihani, N.I. Azkiya, and Y. Nailufa

DOI: http://doi.org/10.31788/RJC.2026.1919583

Biochitosan derived from marine biomass has attracted wide interest in pharmaceutical and biomedical applications due to its biocompatibility and functional amino groups. This study aimed to isolate andcharacterise chitosan from mangrove crab (Scylla paramamosain) shell waste and to evaluate thephysicochemical differences between high molecular weight chitosan (HMWC) and low molecular weight chitosan (LMWC) for their potential use in cocrystal formulations. Chitosan was isolated throughdemineralisation, deproteinization, deacetylation, and decalcification, followed by depolymerisation to obtainLMWC. Physicochemical evaluations included moisture content, ash value, degree of deacetylation (DD), ninhydrin test, SEM morphology, SEM-EDX elemental analysis, FTIR spectroscopy, XRD, and Gel PermeationChromatography (GPC). The results showed that LMWC exhibited superior quality, with lower moisture(3.09%) and ash content (7.41%), and the highest DD (77.76%) compared to HMWC. SEMimages confirmedthat LMWC had a finer and more porous morphology, while SEM-EDX revealed the dominance of carbonandoxygen with undetected nitrogen due to instrumental limitations. FTIR confirmed the presence of –NH₂and–OH groups, and XRD patterns indicated that LMWC exhibited crystallinity more consistent with standardchitosan than HMWC. GPC further demonstrated a significant reduction in molecular weight from73,000Da(HMWC) to 19,000 Da (LMWC), improving solubility and reactivity. Collectively, these findings indicate that LMWC more closely resembles commercial chitosan in structural and functional properties, making it moresuitable for pharmaceutical cocrystal formulation.

Keywords: Biochitosan, Low-High Molecular Weight, Scylla paramamosain, Characterisation, Cocrystal.