Electrospraying as a novel method of particle engineering for drug delivery vehicles.

Encapsulation technologies can be used to preserve therapeutic and bioactive compounds from harsh conditions (e.g., light, moisture, and oxygen) and biological destruction (enzymes, metabolism, and phagocytosis). Encapsulation involves the incorporation of the active moieties into a shell structure (e.g., protein, polysaccharide or lipid-based material). These techniques can improve the physicochemical properties of the encapsulated compounds, provide sustained release to specific organs, "cover up" undesirable properties, and improve their solubility, dispersion, and bioavailability. Different techniques have been applied to encapsulate drug compounds, including emulsification, inclusion complexation, nanoparticulate systems (solid lipid nanoparticles and nanostructured lipid carriers), liposome entrapment, nanoprecipitation, freeze drying, spray drying, etc. However, high temperatures or toxic solvents are used in some of these techniques such as spray drying, and liposome entrapment can degrade the bioactive compounds or reduce their functionality. Electrohydrodynamic spraying (electrospraying) is a versatile tool for liquid atomization by means of electrical forces. This technique is simple and easily controllable without any harsh conditions and could be a promising alternative method to encapsulate sensitive compounds. By optimizing the process variables e.g., properties of polymer solutions (type, viscosity, conductivity), solvent type, process parameters (applied voltage between the needle tip and the collector surface, applied flow rate, distance between the needle tip and the collector, ambient temperature, and relative humidity) this technique can be effectively used for micro- and nanoencapsulation of drug compounds. This article reviews the effects of electrospraying parameters in production of monodisperse particles with well-controlled shapes and high encapsulation efficiency. It also, summarizes the latest reports of encapsulation of therapeutic compounds, and critically discusses the limitations and future perspectives of this technique.

Physicochemical and pharmacological evaluation of carvedilol-eudragit® RS100 electrosprayed nanostructures.

OBJECTIVES: This study was carried out to boost the pharmacologic influence of carvedilol (CAR) (as a poorly water-soluble drug) by developing CAR-eudragit® RS100 (Eud) nanofibers and nanobeads benefiting an electrospraying approach. MATERIALS AND METHODS: CAR-Eud nanoformulations with varying ratios (1:5 and 1:10) at total solution concentrations of 10 %, 15 % and 20 % w/v were formulated. RESULTS: The solution concentration remarkably impressed the size and morphology of the samples; in which, the nanobeads (mean diameter of 135.83 nm) were formed at low solution concentrations and high concentrations led to nanofibers (mean diameter of 193.45 nm) formation. DSC thermographs and PXRD patterns along with FTIR spectrum precisely showed CAR amorphization and no probable chemical interactions between CAR and Eud in the electrosprayed nanosystems. The in vitro release considerations demonstrated that the nanoformulations with the drug: polymer ratios of 1:10 and 1:5 depict rapid dissolution rate compared to the physical mixtures (PMs) and the pure drug. The in vivo studies in Wistar male rats suggested that the electrosprayed nanoformulation (1:10; 20 %) reduced the isoproterenol (ISO) induced elevation of heart rate, necrosis and accumulation of neutrophils in the heart tissue more efficient than the pure drug and PM. CONCLUSION: Our finding illustrated that the electrospraying as a profitable one-step procedure could be productively benefited to improve the physicochemical features and pharmacologic influences of CAR.

Triamcinolone acetonide-Eudragit(®) RS100 nanofibers and nanobeads: Morphological and physicochemical characterization.

CONTEXT AND OBJECTIVE: The aim of the present research was to fabricate triamcinolone acetonide (TA)-Eudragit(®) RS100 nanostructures using the electrospraying method. MATERIALS AND METHODS: The physicochemical properties of the electrosprayed formulations as well as drug release patterns were assessed. The particle size and morphology were evaluated using scanning electron microscopy. X-ray crystallography and differential scanning calorimetry were also conducted to investigate the crystallinity and polymorphic alterations of the drug in the formulations. Probable chemical interactions between the drug and the carrier during the preparation process were analyzed using FT-IR spectroscopy. The drug release kinetic was also considered to predict the release mechanism. RESULTS AND DISCUSSION: Increasing the concentration of injected polymer solution resulted in the formation of more fibers and fewer beads, with the particle diameter ranging from 60 nm to a few micrometers based on the drug: polymer ratio. The drug crystallinity was notably decreased during the electrospraying process; however, no interaction between drug and polymer was detected. The electrosprayed formulations with 1:10 drug: polymer ratio showed an almost similar drug release rate compared to the pure drug, while those with 1:5 ratio revealed slower release profiles. The release data were best fitted to the Weibull model, so that the corresponding shape factor values of the Weibull model were less than 0.75, indicating the diffusion controlled release mechanism. CONCLUSION: Our findings revealed that TA loaded Eudragit(®) RS100 nanofibers and nanobeads were properly prepared by the electrospraying method, which is a simple, surfactant-free and cost effective technique for producing drug: polymer nanostructures.

Application of electrospraying as a one-step method for the fabrication of triamcinolone acetonide-PLGA nanofibers and nanobeads.

The aim of the present project was to prepare triamcinolone acetonide nanofibers and nanobeads with prolonged anti-inflammatory activity. Triamcinolone acetonide-loaded PLGA nanoformulations were prepared by electrospraying method. The physicochemical and morphological properties of the fabricated nanoparticles were characterized as well. In vitro drug release of the prepared formulations was also studied. Differential scanning calorimetry and X-ray powder diffractometery showed that drug crystallinity was notably decreased during the electrospraying process. In vitro dissolution tests verified that the pure drug and physical mixtures had faster drug release pattern compared to the nanoformulations. Electrosprayed samples with the drug:polymer ratio of 1:10 revealed slower release profiles compared to those with a 1:5 ratio. Results obtained from SEM images of the prepared formulations indicated that polymer solution concentration was the critical parameter in the formation of fibers or beads; so that, fiber formation was increased proportionally with increasing polymer concentration. Moreover, the size of obtained nanostructures was also increased in order of polymer concentrations. As a final point, electrosprayed triamcinolone-loaded biodegradable micro/nanofibers and nanobeads with modified physicochemical characteristics and sustained drug release profiles were successfully prepared via simple, one-step and cost effective electrospraying technique.