Cellulose nanocrystals from orange and lychee biorefinery wastes and its implementation as tetracycline drug transporter

Cellulose nanocrystals (CNC) possess many advanced applications such as enzyme immobilization, synthesis of antimicrobial drugs, and drug carriers in therapeutic and diagnostic medicine due to its mechanical, liquid crystalline nature and rheological properties. The present study focuses on the usage of cellulose nanocrystals extracted from organic waste biorefineries like orange and lychee peels, as a drug transporter for the tetracycline antibiotic drug. Since cellulose nanocrystals are nontoxic, they could be used as a potential drug transporter for tetracycline. CNC was obtained from natural products following steps like delignification, bleaching, and hydrolysis of cellulose part of orange and lychee peels. To characterize the extracted CNC, from the fruit peels of orange and lychee, TGA, DSC, SEM, and FTIR analyses were carried out. The acidic pH around 2.0 was maintained for drug adsorption procedures of tetracycline uptake by CNC. Langmuir, Freundlich, Temkin, and Dubinin isotherms were employed to fit the adsorption experimental data, qmax = 139.6 mg/g and 179.1 mg/g for orange and lychee peel-extracted CNC respectively. The in vitro discharge of tetracycline from CNC was supported in phosphoric buffer medium at a pH of 7.2. The maximum tetracycline release was 67.41% for orange peel and 73.19% for lychee peel respectively within a period of 72 h. Thus, the procedure of tetracycline adsorption and desorption from cellulose nanocrystals confirms to be safe without exhibiting any harmful impacts on health.