ELECTROSPUN PV A FIBER MATS AS EXTRACT CARRIERS 2 3 7 variance (ANOVA) followed by an LSD post hoc test. Differences of p 0.05 were considered statistically significant. RESULTS AND DISCUSSION MORPHOLOGY OF NEAT AND GM EXTRACT-LOADED ELECTROSPUN PVA FIBER MATS The 10% w/v PV A solution in distilled water was electrospun under an electrical potential of 15 kV applied over a collection distance of 15 cm (i.e., the electric field of 15 kV/15 cm). Figure la demonstrates a selected SEM image of the electrospun PVA fibers. Clearly, cross-sectionally round fibers with a smooth surface were obtained. The average diameter of these fibers was 197 .3 ± 49.8 nm. Based on the good quality of the obtained fibers, 10% w/v PVA solution was then used as the base solution into which the GM extracts were added. After completely dissolving the GM extracts at 2.5%, 5%, and 10% w/w (based on the weight of PV A), the resulting solutions were electrospun. Selected SEM images of the GM extract-loaded electrospun PVA fibers are shown in Figure 1 b-d. The addition of the GM extracts within the base PVA solution did not affect the morphological ap­ pearance of the obtained fibers, although the fiber diameter tended to decrease as the GM Figure 1. Scanning electron micrograph (10000 x) of electrospun PVA fiber mats. (a) bare electrospun PVA fiber mats. (b) 2.5% initial GM extract-loaded electrospun PVA fiber mats. (c) 5% initial GM extract-loaded electrospun PVA fiber mats. (d) 10% initial GM extract-loaded electrospun PVA fiber mats.

238 JOURNAL OF COSMETIC SCIENCE extract concentration increased (see Table I). The SEM images of the GM extract-loaded electrospun PV A fibers revealed no presence of beads, GM extract crystals, or other types of the extract aggregates on the surface of the fibers. This implies that the GM extracts were incorporated well within the electrospun fibers. SWELLING BEHAVIOR OF NEAT AND GM EXTRACT-LOADED ELECTROSPUN PVA FIBER MATS AND CAST PV A FILMS The degree of swelling of the neat and the GM extract-loaded electrospun PVA fiber mats and films after submersion in distilled water at room temperature for 24 h is illustrated in Figure 2. In each of the sample types investigated, the property values of the electrospun PVA fiber mats were greater than those of the cast PVA films, which should be a result of the highly porous nature of the electrospun fiber mats hence the much greater surface area when compared with that of the cast films. These results are consistent with previous results in which electrospun PVA fiber mats showed a greater degree of swelling than cast PV A films (24). RELEASE OF GM EXTRACTS FROM GM EXTRACT-LOADED ELECTROSPUN PVA FIBER MATS AND CAST PV A FILMS Prior to investigating the release characteristics of the GM extracts from both the GM extract-loaded electrospun PVA fiber mats and cast PVA films, the actual amount of the GM extracts within these samples was measured. Table II summarizes the actual amount of the GM extracts present in these samples (reported as the percentage of the initial content of GM extracts loaded in both the spinning and the casting solutions, i.e., 10 wt% based on the weight of PVA powder). The antioxidant activity was evaluated by using the 2,2-diphenyl-1-picryhydrazyl (DPPH) method. The actual amounts of the GM extracts in electrospun PVA fiber mats that were prepared from the base solution containing 2.5%, 5%, and 10% w/w of the extract were 9.6%, 9.7%, and 10.8% of the initial GM extract loading, respectively. On the other hand, those of the corresponding films were 23.9%, 14.5%, and 21.0%, respectively. Ideally, the actual amount of the GM extracts presented in the drug-loaded cast PVA films should be 100%. The dis­ crepancy from the ideal could be due to the inhomogeneity of the GM extracts in different parts of the samples despite careful preparation of the spinning and the casting solutions, or due to an adverse effect of the sample preparation methods on the anti­ oxidative activity of the loaded GM extracts. The determination of the release characteristics of the GM extracts from the GM extract­ loaded electrospun PVA fiber mats and cast PVA films was carried out by the total Table I Fiber Diameters of Electrospun PVA Fiber Mats With and Without GM Extract Loading Formulation Neat electrospun PVA fiber mats 2.5% GM extract-loaded electrospun PVA fiber mats 5% GM extract-loaded electrospun PVA fiber mats 10% GM extract-loaded electrospun PVA fiber mats Size (nm) 197.3 ± 49.8 159.6 ± 43.1 176.2 ± 58.7 140.7 ± 52.7