Influence of Aqueous Solubility-Enhancing Excipients on the Microstructural Characteristics of Furosemide-Loaded Electrospun Nanofibers

Abstract

Electrospun nanofibers were prepared from furosemide-containing hydroxypropyl cellulose and poly(vinylpyrrolidone) aqueous solutions using different solubility enhancers. In one case, a solubilizer, triethanolamine, was applied, while in the other case a pH-modifier, sodium hydroxide, was applied. Scanning electron microscopy (SEM) was carried out for morphological characterization of the fibers. The SEM images indicated similar mean diameter size of the two fibrous formulations. However, in contrast to the NaOH-containing fibers of normal diameter distribution, the triethanolamine-containing fibers showed approximately normal diameter distribution, possibly due to their plasticizing effect and the consequent slightly ribbon-like morphology. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), powder X-ray diffraction (XRD) and positron annihilation lifetime spectroscopy (PALS) were applied for microstructural characterization. The FTIR measurements confirmed that furosemide salt was formed in both cases. There was no sign of any crystallinity based on the XRD measurements. However, the PALS highlighted the differences in the average o-Ps lifetime values and distributions of the furosemide-loaded fibrous formulations. The two types of electrospun nanofibrous formulations containing amorphous furosemide salt showed similar macrostructures but different microstructural characteristics depending on the type of solubility enhancers, which lead to altered storage stability.

Positron Annihilation Lifetime Spectroscopy as a Special Technique for the Solid-State Characterization of Pharmaceutical Excipients, Drug Delivery Systems, and Medical Devices—A Systematic Review

“…The effects of different solubility enhancers (triethanolamine and pH modifier sodium hydroxide) were examined in PVP and HPC nanofibrous matrices and physical mixtures during accelerated stability testing. In the furosemide-containing fibrous systems, triethalonamine acted as a plasticizer and increased the o-Ps lifetimes compared to the NaOH-containing matrix, which was more densely packed [ 75 ]. Excipients were added to amorphous solid dispersions to improve aqueous solubility and physicochemical stability, and the effects of the polysorbate 80 surfactant and hydroxypropyl-β-cyclodextrin were investigated on the molecular packing of the drug-free and metoclopramide-loaded buccal nanofibers.…”

Green electrospinning for safe food engineering

“…Second, because of the hydrophilicity of high-performance polymers, electrospun fibers lose their mechanical properties due to hydration, which ultimately leads to their complete dissolution 145 . Unfortunately, HPC is mostly used in the biomedical field 146 , and there is no relevant report on its application in food engineering.…”

Image Analysis: A Versatile Tool in the Manufacturing and Quality Control of Pharmaceutical Dosage Forms

“…To analyze the morphology of the AC electrospun nanofibers from SEM images, coating is required to increase the sample conductivity. The application of gold coating is the norm, and the determination of fiber uniformity and individual fiber diameter data for statistical description and comparison is a standard method for morphological studies [ 72 , 73 ]. He et al applied a gold–palladium alloy coating and determined not only the diameters of the 100 randomly chosen fibers but also their orientation by performing fast Fourier transform analyses [ 74 ].…”