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Purpose: The aim of this work was to prepare azithromycin (AZI) nanosuspensions to increase the solubility and dissolution rate. Method: AZI nanosuspensions were prepared by the combination of reactive precipitation and freeze-drying in presence of biocompatible stabilizer. Formulation and process variables affecting the characteristics of nanosuspensions were optimized. Various tests were carried out to study the physicochemical characteristics of AZI nanosuspensions. Results: The nanosuspensions were parenterally acceptable and autoclavable, because soybean lecithin was the stabilizer of choice and no organic solvents were used during the preparation. The mean particle size and zeta potential of the AZI nanosuspensions were about 200 nm (±20 nm) and −36.7 mV (±7.6 mV), respectively. Solid nanoparticles were obtained by lyophilization of the nanosuspensions and nanosuspensions rapidly reconstituted when the nanoparticles were dispersed in water. X-ray diffraction and differential scanning calorimetry analysis showed that the crystal state of nanoparticles was amorphous. Solubility and in vitro release studies indicated that the saturated solubility and dissolution rate increased obviously in comparison of raw AZI. The nanoparticles were physically stable over a period of 5 months as demonstrated by unchanged crystallinity and stable particle size when stored at room temperature and protected from humidity. Conclusion: The results suggested that reactive precipitation is an effective way to prepare AZI nanosuspensions with increased solubility and dissolution rate. [ABSTRACT FROM AUTHOR]

Abstract: Amorphous atorvastatin calcium (AC) ultrafine powder has been successfully prepared by antisolvent precipitation and spray drying process, in which hydroxypropyl methylcellulose (HPMC) was employed to control the particle size and morphology. The effects of experimental parameters, such as stirring time, drug concentration and drying methods, on particle size and morphology were investigated. The average particle size of AC obviously increased from 410nm to 1200nm as the stirring time changed from 30s to 60min. The enhancement of drug concentration favored to decrease the particle size from 410nm to 240nm. After spray drying process, ultrafine AC powder was obtained, which had good dispersibility and narrow particle size distribution of 1–3μm. The as-prepared ultrafine AC was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, thermal gravimetric analysis (TG), differential scanning calorimetry (DSC), specific surface area and dissolution test. The XRD analyses indicated that the ultrafine AC was amorphous. In the dissolution tests, the amorphous AC ultrafine powder exhibited enhanced dissolution property when compared to the raw material. [Copyright &y& Elsevier]

Abstract: The solidification process from emulsion, which consisted of emulsifier, water and molten drug as oil phase without use of any organic solvent, was firstly employed to prepare ultrafine fenofibrate (FF) powder. The effects of stirring speed and volume ratios of hot emulsion to cold water on the particle size and morphology were discussed as well as the impacts of different emulsifiers on emulsion. The produced ultrafine powder was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, specific surface area analysis and a dissolution test. XRD patterns and FT-IR spectra showed that the ultrafine FF was crystalline powder with the structure and the components similar to those of bulk drug. The product had a mean particle size of about 3μm with a narrow distribution from 1μm to 5μm. The specific surface area reached up to 6.23m2/g, which was about 25 folds as large as that of bulk FF. In the dissolution tests, about 96.1% of ultrafine FF was dissolved after 120min, while there was only 38.1% of bulk drug dissolved, proving that the dissolution property of ultrafine FF was significantly improved when compared to commercial drug. [Copyright &y& Elsevier]

Abstract: Direct encapsulation of water-soluble drug into silica microcapsules was facilely achieved by a sol–gel process of tetraethoxysilane (TEOS) in W/O emulsion with hydrochloric acid (HCl) aqueous solution containing Tween 80 and drug as well as cyclohexane solution containing Span 80. Two water-soluble drugs of gentamicin sulphate (GS) and salbutamol sulphate (SS) were chosen as model drugs. The characterization of drug encapsulated silica microcapsules by scanning electronic microscopy (SEM), FTIR, thermogravimetry (TG) and N2 adsorption–desorption analyses indicated that drug was successfully entrapped into silica microcapsules. The as-prepared silica microcapsules were uniform spherical particles with hollow structure, good dispersion and a size of 5–10μm, and had a specific surface area of about 306m2/g. UV–vis and thermogravimetry (TG) analyses were performed to determine the amount of drug encapsulated in the microcapsules. The BJH pore size distribution (PSD) of silica microcapsules before and after removing drug was examined. In vitro release behavior of drug in simulated body fluid (SBF) revealed that such system exhibited excellent sustained release properties. [Copyright &y& Elsevier]

Abstract: Ultrafine gemfibrozil (GEM) was prepared by reactive precipitation process in which methyl cellulose (MC) was employed to inhibit the growth and the agglomeration of particles. The impact of NaOH concentrations on bulk GEM consumption was explored. The effects of H2SO4 concentrations and the drying methods on the particle size and morphology were also discussed. The produced ultrafine powders were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, specific surface area analysis and dissolution test. XRD patterns and FT-IR spectra showed that the as-obtained ultrafine GEM was a crystalline powder with the structure and components similar to those of bulk GEM. The ultrafine GEM had a mean particle size of about 1.25μm with a narrow distribution from 0.6 to 3μm. The specific surface area reached up to 11.01m2/g, which was about 6 times as large as that of bulk GEM. In the dissolution tests, about 91.2% of ultrafine GEM was dissolved after 120min, while there was only 23.6% of bulk GEM dissolved, proving that the dissolution property of ultrafine GEM was significantly enhanced when compared to commercial GEM owing to a decreased particle size and an increased specific surface area. [Copyright &y& Elsevier]

Abstract: Micronized silybin particles were successfully prepared by emulsion solvent diffusion method. Uniform spherical and rod-shaped particles with a mean size of 2.48 and 0.89μm could be obtained using sodium dodecyl sulfate (SDS) concentration of 0.1wt% at 30 and 15°C, respectively. The characterization of silybin particles by SEM and particle size distribution (PSD) indicated that with the increase of temperature from 15 to 30°C, the as-prepared particles became bigger and had a tendency to turn into spherical shapes; with the increase of SDS concentration from 0.02 to 0.1wt%, the span of PSD became narrower while the mean particle size kept almost unchanged. XRD patterns and FT-IR spectra showed that the spherical and rod-shaped silybin particles possessed decreased crystallinity; however, the chemical structure and components were similar to those of the commercial silybin powder. Dissolution tests demonstrated that both of the spherical and rod-shaped silybin particles exhibited significantly enhanced dissolution rate when compared to the commercial silybin powder. [Copyright &y& Elsevier]

A novel double-template route to synthesize silica hollow spheres with mesostructured walls using nano-sized calcium carbonate particles as inorganic templates and cationic surfactant as organic templates at room temperature was presented. X-ray diffraction (XRD), nitrogen adsorption, and transmission electron microscopy (TEM) were employed to characterize the morphologies and mesostructures of the as-prepared silica hollow spheres. The effect of inorganic template/surfactant ratio on the pore structure of the hollow spheres was studied. Experimental results indicated that the hollow spheres had an average diameter of nearly 40 nm with a surface area of ∼766–1050 m2/g. [Copyright &y& Elsevier]

Highlights: [•] High-performance ultrafine budesonide particles were prepared for dry powder inhalation. [•] High pressure homogenization combined with spray drying was adopted. [•] The low-density porous spherical drug agglomerates with a VMD of 2.9μm could be generated. [•] An excellent aerosol performance with a FPFemitted value of 81±3% could be achieved. [•] The pressure, cycle time, initial particle size and concentration had obvious effects. [ABSTRACT FROM AUTHOR]