Spheronized drug microcarrier system from canola straw lignin

Abstract

Inhomogeneous lignin from a canola (rapeseed) straw was isolated and valorized as regularly shaped spherical microparticles for drug delivery formulations. Lignin with a purity of 83% and broad molecular weight distribution (Ð > 5.0) was extracted by alkali pulping and acetylated to increase spheronization ability. Lignins with high degrees of acetylation (0.76 and 0.89) were successfully assembled into microparticles with uniform sizes (approximately 2 μm) and smooth spherical surfaces via solvent–antisolvent precipitation. Hydrophobic coumarin 153 and positively charged ciprofloxacin were used as model drugs to assess the encapsulation and release performance of lignin microparticles. Highly acetylated lignin microparticles displayed encapsulation efficiencies of 89.6% for coumarin 153% and 90.6% for ciprofloxacin. Scanning electron microscope images showed that coumarin 153 was encapsulated in the hydrophobic core, while ciprofloxacin was adsorbed on the less hydrophobic shell. The synthesis of lignin microcarriers not only provides a facile approach to utilizing waste canola straw lignin for drug delivery matrices but also has the potential to serve as an alternative lignin powder feedstock for bio-based materials.

Newly Synthesized Lignin Microparticles as Bioinspired Oral Drug-Delivery Vehicles: Flavonoid-Carrier Potential and In Vitro Radical-Scavenging Activity

“…The increased particle size of the morin-encapsulated lignin particles could be attributed to the spatial arrangement of the O-containing functional groups of lignin interacting with the phenolic groups of the encapsulated morin molecules leading to the formation of morin-monolignol units via a mechanism of radical coupling [33]. Similar results were reported by other authors [14].…”

“…Provoked by the latter, nowadays, the design of nano-/micro-formulations based on lignin has gained interest for application as drug delivery systems due to their potential as entrapping and encapsulation vehicles of pesticides, drugs and enzymes, as surfactants, as reinforcing agents in nanocomposites, sorbents for heavy metal ions, organic priority pollutants [8] and other environmental contaminants and for antibacterial and antioxidant applications [9,10]. The literature reports diverse approaches for the production of micro-/nano-scale lignin formulations: solvent/pH shifting [11], acid-catalysed precipitation; flash precipitation [12], dialysis, supercritical antisolvent process, W/O microemulsion methods [13], spray drying, polymerization, ice-segregation, aerosol processing, mechanical processing [9], interfacial crosslinking, self-assembly via emulsion-solvent diffusion, emulsion solvent evaporation, antisolvent precipitation, sonochemical synthesis [14][15][16][17]. Spherical lignin micro-/nanoparticles exhibit superior properties as compared to powdered lignins, such as excellent surface activity, high UV shielding, significant oxidation resistance, and satisfactory antimicrobial potential, etc.…”

“…Spherical lignin micro-/nanoparticles exhibit superior properties as compared to powdered lignins, such as excellent surface activity, high UV shielding, significant oxidation resistance, and satisfactory antimicrobial potential, etc. [14]. According to the study of Gomide et al (2020), the ultrasonic treatment of lignin particles leads to a reduction in their size, which provokes a decrease in the zeta potential and lower probability of agglomeration and increases the thermal stability and the antioxidant potential of the microparticles [9].…”

“…The three-dimensional polymer structure of lignin, comprising of both hydrophobic and hydrophilic groups, determines its applicability and efficiency in tissue engineering and in drug/gene transport, as well as its compatibility with biological media [16,17]facts that explicate the constantly increasing scientific interest towards the biopolymer as a potential source for the synthesis of controlled delivery carriers [14].…”

“…Modern scientific literature provides evidence that in vitro systems for drug delivery based on micro-/nano biopolymer carriers ensure the integration of bioactive molecules and protect them from degradation along their physiological distribution pathways, thus meeting the challenging objective of their delivery to a specific area of therapeutic action [14].…”