In recent years, more and more newly discovered active pharmaceutical ingredients have poor water solubility, which makes further drug development challenging. Nanofibers, due to their remarkable properties, enable better dissolution of the incorporated poorly soluble drug compared to the pure drug. The aim of this master thesis was to investigate the technological procedures and characteristics of poorly water-soluble drug-loaded hydrophilic nanofibers. After reviewing the Pubmed database for published articles, we found 47 articles that met the inclusion criteria. The analysis of the selected articles revealed that scientists have tried to improve solubility of different active pharmaceutical ingredients, many of which belong to the therapeutic group of anti-inflammatory and anti-rheumatic drugs and to class II biopharmaceutical clasification system. Most commonly used materials for production of nanofibers were different polymers and cyclodextrins. Most commonly represented among polymers were polyvinylpyrrolidone and polyethyleneoxide. Nanofibers were loaded with different amounts of drug: most often 10 % (w/w), whereas precipitation of the dissolved drug may occur at drug content 50 % (w/w) or more. Various excipients, most commonly solubilizers, were incorporated to further improve the drug dissolution, increase the processability of the nanofiber formulation, and protect the incorporated drug. Electrospinning has been the most common method used to produce nanofibers. With modifications of the conventional method, scientiest have been able to produce more complex nanofibers with improved properties and to produce nanofibers on larger scale. In more than 70 % of the studies, the drug was converted into stable amorphous form during nanofiber fabrication, which was one of the most important reasons for incresed drug solubility. The dissolution enhancement factor was at least 1 in most formulations compared to the crystalline drug or its physical mixture. This is due to the high specific surface area per unit mass and the porous structure of the nanofiber web, as well as the amorphous form of the incorporated drug. The scientists have more often produced immediate-release rather than modified-release dosage forms. In four studies they have also produced final dosage form.
In conclusion, hydrophilic nanofibers represent a promising approach to improve the solubility and dissolution rate of poorly water-soluble drugs, however further research is still needed for their market entry and widespread use.
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