## 1 Introduction
However, they have a better dissolution-improving effect on solid dispersions (SDs) nanofibers for poorly water-soluble drug model such as acetaminophen, VB\({}_{12}\) (Vitamine B12) and ferulic acid [25; 26; 27]. Clotrimazole (CZ)-loaded PVP nanofibers have a complete drug release in contrast to CZ powder can kill the Candida faster; hence can be used as fast-acting clotrimazole composite nanofibers for oral candidiasis application [28; 29]. [PERSON] et al. proved that the release of ketoprofen from PVP fibers is complete and immediate. Yet, the addition of water-insoluble polymer EC (Ethyl cellulose) can control the dissolution rate and sustained over 24 h [30]. Moreover, the addition of zein to PVP can lead to the sustained release of a drug over 12 h without burst release [31] confirming that blends containing PVP have lower dissolution rate than that for PVP alone. Adding PVP to PLA can improve the drug release of poorly-soluble drugs [32]. In addition to electrospun PVP, electrospun PVA have also been used as a drug-delivery system with different types of drugs [33; 34; 35]. PVA is a water-soluble, biocompatible and biodegradable polymer with widespread use in biomedical applications. [PERSON] et al. 's study on the drug release properties of PVA demonstrated that the drug can rapidly dissolve in the water in a burst manner (caffeine to an extent of 100% and riboflavin to an extent of 40% within 60 s) from the PVA nanofibrous matrices [36]. PVA nanofibers with diameters of 100-300 nm containing donepezil-HCl demonstrate immediate release of the active agent (within 30 s), whereas the complete release time of the corresponding cast films (thickness 100 mm) was 30 min [37]. The initial disintegration time of PVA fibers were decreased from a few weeks to a few seconds by the addition of randomly-methylated b-cyclodextrintrin (b-CD), thus increasing the release rate of haloperidol from the blend fibers [38]. PVA-based curcumin-loaded fibers also exhibited such a rate improvement at lower levels of drug content [39]. A decrease in the rate of release from PVA fibers in the range of 1-24 h was also observed after the treatment of PVA mats with methanol (physical cross-linking) [40; 41]. Poly (p-xylylene) coating to electrospun PVA/BSA fibers resulted in the diminishment of burst release and the significant retardation of protein release compared to untreated fibers [42; 43]. The addition of other hydrophobic polymers to PVA could help to better release the polymer [44; 45]. In another to study the effect of PVA increase on PVP, [PERSON] et al. [46] examined PVA/PVP composite nanofibers and found the sustained release of ciprofloxacin hydrochloride antibiotic by the membranes. Their findings confirmed that PVP substitution in PVA could improve the ultimate yield strength and Young's modulus of the membranes. High fluid uptake and slow degradation of these membranes confirmed that these membranes maintain a moist environment which is very important for fast wound healing. Nevertheless, to the best of the authors' knowledge, the effect of cross-linking or addition of drugs with lower solubility in water on PVA/PVP nanofibers has not been studied yet.