Physicochemical Properties and In Vitro Dissolution of Spiramycin Microparticles Using the Homogenate-Antisolvent Precipitation Process

Preparation of Daidzein microparticles through liquid antisolvent precipitation under ultrasonication

In this study, daidzein microparticles (DMP) were prepared using an improved ultrasound-assisted antisolvent precipitation method. Preliminary experiments were conducted using six single-factor experiments, and principal component analysis (PCA) was adopted to obtain the three staple elements of the ultrasonic power, solution concentration, and nozzle diameter. The response surface Box-Behnken (BBD) design was used to optimize the level of the above factors. The optimal preparation conditions of the DMP were obtained as follows: the flow rate was 4 mL/min, the concentration of the daidzein solution was 16 mg/mL, the ratio of antisolvent to solvent (liquid-to-liquid ratio) was 9, the nozzle diameter was 300 μm, the ultrasonic power was 180 W (665 W/L), and the system speed was 760 r/min. The minimum average particle size of DMP was 181 ± 2 nm. The properties of daidzein particles before and after preparation were analyzed via scanning electron microscopy, X-ray diffraction analysis, Differential scanning calorimetry and Fourier transform infrared spectroscopy, no obvious change in its chemical structure was observed, but crystallinity was reduced. Compared with daidzein powder, DMP has a higher solubility and stronger antioxidant capacity. The above results indicate that the improved method of ultrasonication combined with antisolvent can reduce the size of daidzein particles and has a great potential in practical production.

Experimental study on the reduction of loratadine particle size through confined liquid impinging jets

The confined liquid impinging jets (CLIJ) technique was applied as a simple and effective approach to reducing the particle size of loratadine to enhance its solubility. The effect of anti-solvent (AS) to solution (S) flow rate ratio, organic phase concentration, Reynolds number (Re), and stabilizer concentration was investigated in this reduction process. After the synthesis, the chemical and physical properties of loratadine nanoparticles were determined through different characterization and analytical techniques. The results indicated that the particle size of loratadine decreases from 320 nm to 80 nm by increasing the AS/S ratio from 1 to 25. It was found that the particle size of loratadine was unchanged at the higher AS/S ratios. The loratadine nanoparticle size was optimized by changing the solution concentration, Re, and Tween 80 as a stabilizer. The finest loratadine nanoparticle size of about 53 nm was obtained with a narrow size distribution, which corresponds to solution concentration of 35 mg/mL, Re of 5687, and 0.1% (w/v) stabilizer concentration. It was revealed that the optimized loratadine nanoparticles completely dissolved after 11 min, indicating the loratadine nanoparticle dissolution rate 50 times faster than raw loratadine.

Enhancement of the apparent solubility and bioavailability of Tadalafil nanoparticles via antisolvent precipitation

The ability to increase the bioavailability and dissolution of poorly soluble hydrophobic drugs has been a major challenge for pharmaceutical development. This study shows that the dissolution rate, apparent solubility and oral bioavailability of tadalafil (Td) can be improved by nano-sized amorphous particles prepared by using antisolvent precipitation. Acetone and an acetone-water solution (v:v, 9:1) were selected as solvents, with deionized water as the antisolvent. The antisolvent precipitation process was conducted at a constant drug concentration of 10 mg/ml, at temperatures of 5, 10 and 15 °C and at volume ratios of antisolvent to solvent (AS/S) of 5, 8 and 10. Solid dispersion was achieved by dissolving the polymer in the antisolvent prior to the precipitation and by spray drying the suspension after the antisolvent precipitation process. The selected polymers were HPMC, VA64, and PVPK30 at concentrations of 33, 100 and 300 mg per 100 ml of water (equivalent to weight ratios of drug-to-polymer of 1:3, 1:1 and 3:1, respectively). The solid dispersions were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC) and fourier transform infrared spectroscopy (FT-IR). The improvements in the dissolution rate, equilibrium solubility, apparent solubility and bioavailability were tested and compared with unprocessed Td. Td particles in the suspension (before spray drying) were 200 nm, and the obtained Td solid dispersion had a size of approximately 5-10 μm. The XRPD, DSC and FT-IR analyses confirmed that the prepared Td particles in the solid dispersions were amorphous. The solid dispersion obtained using the optimized process conditions exhibited 8.5 times faster dissolution rates in the first minute of dissolution, 22 times greater apparent solubility at 10 min and a 3.67-fold increase in oral bioavailability than the as-received Td. The present work demonstrated that low temperature antisolvent precipitation technique has excellent potential to prepare nano-sized amorphous particles with a faster release and a higher bioavailability.

Joint tagging assisted fluctuation nanoscopy enables fast high-density super-resolution imaging

In fluctuation-based optical nanoscopy, investigating high-density labeled subcellular structures with high fidelity has been a significant challenge. In this study, based on super-resolution radial fluctuation (SRRF) microscopy, the joint tagging (JT) strategy is employed to enable fast high-density nanoscopic imaging and tracking. In fixed cell experiment, multiple types of quantum dots with distinguishable fluorescence spectra are jointly tagged to subcellular microtubules. In each spectral channel, the decrease in labeling density guarantees the high-fidelity super-resolution reconstruction using SRRF microscopy. Subsequently, the combination of all spectral channels achieves high-density super-resolution imaging of subcellular microtubules with a resolution of ~62 nm using JT assisted SRRF technique. In the live-cell experiment, 3-channel JT is utilized to track the dynamic motions of high-density toxin-induced lipid clusters for 1 minute, achieving the simultaneous tracking of many individual toxin-induced lipid clusters spatially distributed significantly below the optical diffraction limit in living cells.

Antisolvent precipitation for the preparation of high polymeric procyanidin nanoparticles under ultrasonication and evaluation of their antioxidant activity in vitro

An improved method of ultrasonic antisolvent precipitation was used to prepare micronized high polymeric procyanidins (HPC). Response surface methodology (Plackett-Burman and Box-Behnken design) was employed to predict the optimal preparation conditions and satisfactory mean particle size. Among seven parameters, three parameters (i.e., ultrasonic irradiation power, ultrasonic-stirring time, and stirring speed) were identified as the most significant variables using Plackett-Burman design; thus, these three parameters were further optimized using Box-Behnken design. The optimal preparation conditions for micronized HPC were obtained as follows: dropping speed of 4 mL/min, HPC solution concentration of 0.3 mg/mL, ratio of antisolvent and solvent of 5 mL/mL, precipitation temperature of 10 °C, ultrasonic-stirring time of 14 min, ultrasonic irradiation power of 620 W, and stirring speed of 760 r/min. A minimum mean particle size of 96 ± 2 nm was achieved under the aforementioned conditions. The obtained micronized HPC was analysed by scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric and X-ray powder diffraction patterns. Micronized HPC enjoyed the higher quantity dissolved and exhibited stronger antioxidant activity in compared to the unprocessed HPC. These results demonstrated that the improved method has great potential for the production of micronized particles.

Metal oxide nanoparticle-functionalized sebacic acid-grafted PHEAM nanocarriers for enriched activity of metronidazole against food borne bacteria: in vitro and in vivo study

Food borne infection is a serious complication caused by Listeria monocytogenes (L. monocytogenes), a dangerous bacteria.