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%. Disintegration testing demonstrated rapid disintegration for gelatin tablets (0.52 min), whereas alginate formulations exhibited concentration-dependent prolongation from 4.62 to 21.20 min. FCTa4 displayed sustained-release characteristics due to hydrogel matrix formation by sodium alginate. Thermogravimetric analysis (TGA/DTA) confirmed adequate thermal stability of the formulations with characteristic moisture loss below 150？C and gradual decomposition at elevated temperatures. SEM micrographs revealed highly porous and heterogeneous surface morphology favorable for adsorption activity. FTIR spectra showed broad O–H stretching bands at 3200 - 3500 cm？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.
Cite this paper
Awodi, G. O. , Itodo, A. U. , Wuana, R. A. , Ande, S. and Sumi, R. B. (2026). Development of Sustainable Activated Carbon Tablets from Coconut Shell: Formulation and Binder Optimization Studies. Open Access Library Journal, 13, e15584. doi: http://dx.doi.org/10.4236/oalib.1115584.
Tan, I.A.W., Ahmad, A.L. and Hameed, B.H. (2008) Preparation of Activated Carbon from Coconut Husk: Optimization Study on Removal of 2,4,6-Trichlorophenol Using Response Surface Methodology. <i>Journal</i> <i>of</i> <i>Hazardous</i> <i>Materials</i>, 153, 709-717. <br>https://doi.org/10.1016/j.jhazmat.2007.09.014
United States Pharmacopeia (2024) United States Pharmacopeia and National Formulary (USP 47-NF 42). United States Pharmacopeial Convention. <br>https://www.uspnf.com
Taylor, K.M.G. and Aulton, M.E. (2022) Aulton’s Pharmaceutics: The Design and Manufacture of Medicines. 6th Edition, Elsevier. <br>https://www.elsevier.com/books/aultons-pharmaceutics/taylor/978-0-7020-8154-5
Allen, L. (2021) Ansel’s Pharmaceutical Dosage Forms and Drug Delivery Systems 12th Edition. Wolters Kluwer. <br>https://shop.lww.com/Ansel-s-Pharmaceutical-Dosage-Forms-and-Drug-Delivery-Systems/p/9781975171773
Coates, J. (2020) Interpretation of Infrared Spectra, a Practical Approach. In: Meyers, R.A., Ed., <i>Encyclopedia of Analytical Chemistry</i>:<i> Applications</i>,<i> Theory and Instru</i><i>mentation</i>, John Wiley & Sons, 10815-10837. <br>https://doi.org/10.1002/9780470027318.a5606
Builders, P.F., Mbah, C.C. and Attama, A.A. (2011) Intrinsic and Compaction Properties of a Microcrystalline Cellulose Material Derived from the Agricultural Waste of Sorghum Bicolor. <i>International Journal of Pharmaceutics</i>, 414, 154-163.
Eraga, S.O., Meko, O.A. and Iwuagwu, M.A. (2019) Evaluation of Xerogels of Cassava and Cocoyam Starches as Dry Granulation Binders and Disintegrants in Directly Compressed Paracetamol Tablet Formulations. <i>Pharmaceutical and Biomedical Research</i>, 4. <br>https://doi.org/10.18502/pbr.v4i4.545
Aulton, M.E. and Taylor, K.M.G. (Eds.) (2022) Aulton’s Pharmaceutics: The Design and Manufacture of Medicines. 6th Editon. Elsevier. <br>https://www.educate.elsevier.com/book/details/9780702081545
Jadach, B., Świetlik, W. and Froelich, A. (2022) Sodium Alginate as a Pharmaceutical Excipient: Novel Applications of a Well-Known Polymer. <i>Journal</i> <i>of</i> <i>Pharmaceutical</i> <i>Sciences</i>, 111, 1250-1261. <br>https://doi.org/10.1016/j.xphs.2021.12.024
Sun, Y., Zhang, H., Yuan, N., Ge, Y., Dai, Y., Yang, Z. and Lu, L. (2021) Phosphorylated Biomass-Derived Porous Carbon Material for Efficient Removal of U(VI) in Wastewater. <i>Journal of Hazardous Materials</i>, 413, Article 125282. <br>https://doi.org/10.1016/j.jhazmat.2021.125282
Shiga, T. and Takei, T. (2021) Influence of Sodium Alginate and Gelatin Binder Concentrations on the Mechanical Stability and Porosity of Composite Matrix Tablets. <i>Materials Chemistry and Physics</i>, 263, Article ID: 124395.
Sanchez-Ballester, N.M., Bataille, B. and Soulairol, I. (2021) Sodium Alginate and Its Applications in Pharmaceutical Dosage Forms. <i>Carbohydrate Polymers</i>, 270, Article 118399. <br>https://doi.org/10.1016/j.carbpol.2021.118399
