Effect of shrimp shells milling on the molar mass of chitosan

Alternative methods for the pilot-scale production and characterization of chitosan nanoparticles

This work describes the production/characterization of low molar mass chitosan nanoparticles derived from waste shrimp shells (SSC), as well as from a commercial chitosan (CC). The production of low molar mass nanochitosan employed thermal shock, alternating between 100 °C and ambient temperature, followed by grinding the dry material (SSC and CC) in a ball mill, producing around 500 g of nanochitosan per batch. A highlight of the methodology employed is that it enables nanochitosan to be obtained even from a low quality commercial raw material. All particles had diameters smaller than 223 nm, with an average diameter below 25 nm (determined by DLS), while reductions of molar mass were between 8.4-fold and 13.5-fold. The depolymerization process resulted in a reduction in crystallinity of 38.1 to 25.4% and 55.6 to 25.9% in the CC and SSC samples, respectively. The production of nanochitosans was also confirmed by TEM through the observation of crystalline domains with diameters between 5 and 10 nm. This work perfectly reproduces the results on bench scale from previous research. The simple and inexpensive processes enable easy scale-up, representing an important advance in the production chain of biopolymers. Graphical abstract.

Understanding the Performance of a Novel Direct Compression Excipient Comprising Roller Compacted Chitin

Chitin has been investigated in the context of finding new excipients suitable for direct compression, when subjected to roller compaction. Ball milling was concurrently carried out to compare effects from different energy or stress-inducing techniques. Samples of chitin powders (raw, processed, dried and humidified) were compared for variations in morphology, X-ray diffraction patterns, densities, FT-IR, flowability, compressibility and compactibility. Results confirmed the suitability of roller compaction to convert the fluffy powder of raw chitin to a bulky material with improved flow. X-ray powder diffraction studies showed that, in contrast to the high decrease in crystallinity upon ball milling, roller compaction manifested a slight deformation in the crystal lattice. Moreover, the new excipient showed high resistance to compression, due to the high compactibility of the granules formed. This was correlated to the significant extent of plastic deformation compared to the raw and ball milled forms of chitin. On the other hand, drying and humidification of raw and processed materials presented no added value to the compressibility and compactibility of the directly compressed excipient. Finally, compacted chitin showed direct compression similarity with microcrystalline cellulose when formulated with metronidazole (200 mg) without affecting the immediate drug release action of the drug.

Anti-proliferative effect of chitosan nanoparticles (extracted from crayfish Procambarus clarkii, Crustacea: Cambaridae) against MDA-MB-231 and SK-BR-3 human breast cancer cell lines

Actually, the most common cancer in women is the breast cancer which is the second most widespread cancer overall. In 2018, there were over two million new cases of women breast cancer. Particularly, we tried to extract chitosan from crayfish Procambarus clarkii, Crustacea: Cambaridae, by N-deacetylation of chitin. The chemical structure of chitosan was characterized by Fourier transform infrared (FT-IR) spectroscopy. Also DDA was calculated from FT-IR and ultraviolet spectrophotometry data. Chitosan nanoparticles were prepared using a ball-milling technique. The as-prepared chitosan nanoparticles were characterized by transmission electron microscopy, dynamic light scattering as well as zeta potential. The cytotoxicity of chitosan and its nanoparticles (50 and 100 μg/mL) against human breast cancer (SK BR3 and MDA-MB-231 cell lines) was evaluated. MTT assay asserts the significant inhibitory action of both chitosan and its nanoparticles on the proliferation of human breast cancer cells in vitro. Chitosan nanoparticles had more anti-proliferative effects on MDA-MB-231 and SK-BR-3 cell lines than its corresponding chitosan. Although, chitosan nanoparticles, that has higher DDA, had a higher cytotoxic activity against human breast cancer MDA-MB-231 and SK-BR-3 cell lines in vitro. Eventually, chitosan and its nanoparticles can be considered as a promising natural compounds in human breast cancer treatment.