Bio-chemical Preparation of Microcrystalline Cellulose Powder from Cotton Linters for Utilization as Tablet Excipients

Aims: The present work is aimed to prepare microcrystalline cellulose (MCC) powder from cotton linters by an eco-friendly bio-chemical process and to evaluate the prepared MCC as tablet excipients.

Study Design: Randomized Complete Block Design.

Place and Duration of Study: Ginning Training Center, ICAR-Central Institute for Research on Cotton Technology, Nagpur, Maharashtra, India during June to December, 2019.

Methodology: The MCC was prepared from cotton linters by enzymatic and chemical methods and compared with commercial grade MCC (Avicel® PH101). The crude enzyme extract of Aspergillus sp. VM-1 was obtained by solid-state fermentation and used for hydrolysis of cotton linters at 60℃ for 60 min. In the chemical process, 10% alkali was used for hydrolysis at boiling temperature for 60 min. In both the processes, the hydrolyzed cotton linters were bleached with hydrogen peroxide. The MCC powders were characterized for physico-chemical and tableting properties based on Indian Pharmacopeia (IP) and Untied States Pharmacopeia (USP) specifications.

Results: The α-cellulose content (%) in the synthesized MCC by enzymatic process was 98.1 while the commercial grade MCC, Avicel® PH101 had 98.5. The physico-chemical properties of synthesized MCC by enzymatic process were comparable with Avicel PH101 and meet the IP standards. The degree of polymerization (DP) of prepared MCC and Avicel PH101 were 215 and 157, respectively. The FT-IR spectrum of synthesized MCC had similarity to that of Avicel® PH101. The tableting properties of prepared MCC met USP standards. The MCC prepared from cotton linters by enzymatic was found to be superior to chemical process with respect to cellulose yield, degree of polymerization and tablet dissolution property.

Conclusion: The results showed MCC synthesized from cotton linters through enzymatic route is a promising candidate for direct compressible excipient of tablet. The present study highlights that the enzymatic process significantly reduces the alkali usage and heating temperature and thus saves the chemicals and energy in the process.