The aim of this study is to prepare a dual layer polyvinyl (PVA) patch using a combination of electrospinning techniques and cryogelation (freeze-thaw process) then subsequently to investigate the effect of freeze-thaw cycles, nanofiber thickness, and diclofenac sodium (DS) loading on the physicochemical and mechanical properties and formulation of dual layer PVA patches composed of electrospun PVA nanofibers and PVA cryogel. After the successful preparation of the dual layer PVA patch, the prepared patch was subjected to investigation to assess the effect of freeze-thaw cycles, nanofiber thickness and percentages of DS loading on the morphology, physiochemical and mechanical properties. Various spectroscopic techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), water contact angle, and tensile tests were used to evaluate the physicochemical and mechanical properties of prepared dual layer PVA patches. The morphological structures of the dual layer PVA patch demonstrated the effectiveness of both techniques. The effect of freeze-thaw cycles, nanofiber thickness, and DS percentage loading on the crystallinity of a dual layer PVA patch was investigated using XRD analysis. The presence of a distinct DS peak in the FTIR spectrum indicates the compatibility of DS in a dual layer PVA patch through in-situ loading. All prepared patches were considered highly hydrophilic because the data obtained was less than 90°. The increasing saturation of DS within the PVA matrix increases the tensile strength of prepared patches, however decreased its elasticity. Evidently, the increasing of electrospun PVA nanofibers thickness, freeze-thaw cycles, and the DS saturation has improved the physicochemical and mechanical properties of the DS medicated dual layer PVA patches, making them a promising biomaterial for transdermal drug delivery applications.

No abstract

Transdermal drug delivery systems (TDDS) have drawn more interest from pharmaceutical scientists because they could provide steady blood levels and prevent the first-pass metabolism over a longer period. Polyvinyl alcohol (PVA) has been widely used in this application due to its biocompatibility, non-toxicity, nanofiber and hydrogel-forming ability. Despite those benefits, their morphology would easily be destroyed by continuous water absorption and contribute to burst drug release due to its hydrophilicity. The aim of this study was to prepare the diclofenac sodium (DS)-medicated dual layer PVA patch using a combination of electrospinning and cryogelation (freeze–thaw) methods to improve the physicochemical properties and drug compatibility and investigate the release of the DS-medicated dual layer PVA patch. Morphological observations using scanning electron microscopy (SEM) verified the polymer−polymer interaction between both layers, whereas Fourier transform infrared (FTIR) spectroscopy has demonstrated the compatibility of DS in PVA matrix up to 2% w/v of PVA volume. The DS loads were found amorphously distributed efficaciously in PVA matrix as no visible spectra of DS–PVA interaction were detected. The DS-medicated dual layer PVA patch with a thicker nanofiber layer (3-milliliter running volume), three freeze–thaw cycles and 2% DS loading labeled as 2%DLB3C show the lowest swelling capacity (18.47%). The in vitro assessment using Franz diffusion cells showed that the 2%DLB3C indicates a better sustained release of DS, with 53.26% of the DS being released after 12 h. The 2%DLB3C owned a flux (Jss) of 0.256 mg/cm2/h and a permeability coefficient (Kp) value of 0.020 cm/h. Thus, the results demonstrate that DS-medicated dual layer PVA patches prepared via a combination of electrospinning and cryogelation are capable of releasing drugs for up to 24 h and can serve as a drug reservoir in the skin, thereby extending the pharmacologic effects of DS.

Wood dust filler-polymer foam composite has been studied and proved to have ability to absorb sound. In this study, treated rubber and Meranti wood dust named as RA and MA respectively was use as the filler. This study was developed to compare the behavior of sound absorption based on treated filler and particle size of wood dust. By choosing the size of 355 and 710 μm, three different percentages has been selected which is 10%, 15% and 20% for both type of wood dust. These samples has been tested by using Impedance Tube test for sound absorption coefficient (α) measurement and Noise Reduction Coefficient measurement (NRC) and Scanning Electron Microscopy (SEM) to determine the diameter of pore for selected size and type of wood dust-polymer foam composite. The pore size and structure was influence the sound absorption behavior of each sample. 355 μm-polymer foam composite of every percentage loading shows the uniform pore structure as compared to 710 μm of particle size. NRC results shows that increasing pore size has decrease the NRC value. It is therefore, concluded that the sound absorption coefficient for eachsound absorbing material, with different sizes of wood dust particles, types of wood dust and the percentages of wood dust loading in polymer foam matrix effect the sound absorption behavior.

No abstract