Controlled Release of Theophylline-Chitosan Composite Particles Prepared Using Supercritical Assisted Atomization

Abstract

This study investigated the formation of composite particles of chitosan (CS) and theophylline (TPH) via supercritical assisted atomization (SAA) using aqueous ethanol (50%, v/v) as the solvent and supercritical CO 2 as the spraying medium. According to XRD, DSC, and FTIR analyses, the crystal form of the SAA-treated TPH from the as-received TPH was unchanged. The effect of different mass ratios of CS to TPH on the in vitro release of TPH showed that the dissolution of the highly water-soluble TPH was retarded when included in the composite particles and could be controlled by the mass ratio of the component in the SAA process. The in vitro dissolution data showed a good fit with the Peppas-Sahlin model, which was used to conclude that the drug release from the composite particles resulted from a combination of drug diffusion and relaxation of the polymer. As the mass ratio of CS to TPH increased, the mechanism relating to polymer relaxation became crucial in the TPH-CS composite particles.

Nanoparticles and Nanocrystals by Supercritical CO2-Assisted Techniques for Pharmaceutical Applications: A Review

“…Water, ethanol, methanol, and acetone are mainly employed, pure or mixed, to process active compounds using the SAA technique. However, until now, sub-micrometric particles have mostly been prepared by SAA [136][137][138][139], while pharmaceutical nanoparticles have been produced in few papers [36,133,140]. Briefly, SAA is based on the solubilization of a controlled amount of scCO 2 in a liquid solution consisting of the solvents and solutes to be nanonized.…”

“…When operating at low GLR values, as well as at low temperatures in the precipitator, the time required for the complete evaporation of the liquid solvents increases; thus, the precipitation of the solute/solutes occurs slowly. A GLR value of 1.8 has often been found to be the most effective for the attainment of spherical particles by SAA [133,136,137,139,141]. The concentration of the solute/solutes in the liquid solution can also strongly influence the particle size [133,138,142].…”

Biopesticide Encapsulation Using Supercritical CO2: A Comprehensive Review and Potential Applications

“…This is a two-step atomization: first, there is pneumatic atomization, in which a pressure drop occurs at the nozzle outlet, and then there is decompressive atomization, by steadily delivering CO 2 in the primary droplets. The microparticles are formed through the evaporation of the solvent and supersaturation of the solute in the droplets ( Figure 4 ) [ 97 ].…”

“…This technique has been used with different compounds: active molecules, proteins, and polymers [ 81 ]. SAA can be applied with an organic and aqueous solvent, and it is a flexible and easily scalable process [ 97 ]. Even though this process presents some limitations for thermolabile compounds due to the high temperature required, this problem can be overcome by applying a vacuum in the precipitator [ 78 ].…”

Effect of the Carrier on the Coprecipitation of Curcumin through Supercritical-Assisted Atomization

“…Among the different techniques, supercritical antisolvent precipitation (SAS) and supercritical-assisted atomization (SAA) have been frequently and efficiently used to obtain coprecipitated microparticles constituted by a polymeric matrix in which the API is dispersed [23][24][25][26][27][28]. The role that scCO 2 has played in the two processes is conceptually different.…”