TITLE:
Development of Sustainable Activated Carbon Tablets from Coconut Shell: Formulation and Binder Optimization Studies
AUTHORS:
Godwin Owoicho Awodi, Adams Udoji Itodo, Raymond Ahule Wuana, Sesugh Ande, Roselyn Benjamin Sumi
KEYWORDS:
Carbo Tablets, Activated Carbon, Coconut Shell, Sodium Alginate, Gelatin Binder, Physicochemical Evaluation
JOURNAL NAME:
Open Access Library Journal,
Vol.13 No.7,
July
22,
2026
ABSTRACT: This study investigated the formulation, physicochemical evaluation, and instrumental characterization of sustainable carbo tablets prepared from coconut shell-derived activated carbon using gelatin and sodium alginate as binder systems in accordance with United States Pharmacopeia (USP 30) standards. Five formulations comprising gelatin-based tablets (FCTG) and sodium alginate formulations containing 1% - 4% binder concentrations (FCTa1-FCTa4) were developed and compared with a commercial carbo tablet (CCT). Pre-compression evaluation showed excellent granule flowability with angle of repose values ranging from 25˚ - 27˚, bulk density between 0.53 - 0.57 g/cm3, and tapped density of 0.67 - 0.71 g/cm3, indicating suitability for tablet compression. Mechanical studies revealed progressive increases in crushing strength from 3.4 kgf (FCTa1) to 6.4 kgf (FCTa4) with increasing sodium alginate concentration, while friability decreased correspondingly. FCTG (0.4%), FCTa3 (0.80%), and CCT (0.4%) complied with the pharmacopeial friability requirement of −1, aliphatic C–H peaks near 2900 cm−1, carbonyl and aromatic C=C bands around 1600 - 1700 cm−1, and C–O/C–O–C stretching vibrations within 1000 - 1300 cm−1, confirming the presence of hydroxyl, carbonyl, aromatic, and polysaccharide functional groups without evidence of chemical incompatibility. EDX analysis verified the predominance of carbon and oxygen within the formulations, confirming the carbon-rich composition of the activated carbon tablets. Among all formulations, FCTa3 demonstrated the most balanced pharmaceutical performance in terms of hardness, friability, disintegration, thermal stability, and structural integrity. The study highlights the potential of sodium alginate as an effective natural binder and demonstrates the feasibility of utilizing coconut shell-derived activated carbon as a sustainable pharmaceutical material for carbo tablet formulation.