The purpose of this study was to develop transdermal films (TFs) with the addition of different polymer ratios that incorporated 0.5% tenoxicam in order to ensure maximum controlled and sustained ...drug release capacity. Tenoxicam is a non-steroidal anti-inflammatory drug (NSAID) widely used in the treatment of rheumatic diseases and characterized by its efficacy and reduced side effects in comparison to other NSAIDs.
Transdermal films of tenoxicam were designed with the Eudragit L30D-55copolymer with permeation enhancers like polyethylene glycol (PEG) and propylene glycol (PG) incorporated at different concentrations using the casting evaporation technique. Evaluations of these formulae were performed through mechanical characterizations and Fourier Transform Infrared Spectroscopy FTIR. In-vitro release studies were performed during 24
h using diffusion cells. The film formulations with optimum in vitro-release rate have been taken up for testing of the anti-inflammatory effects and the sustaining action of tenoxicam. The in-vivo studies performed included carrageenan-induced hind paw edema and skin biopsies in Wistar rats.
Formulation (F7) had the best effective combination glycerol (0.25
g), PEG200 (0.5
g), PEG400 (1
g) and PG (10%) and 0.5% dispersed drug among all of the tenoxicam TF formulations studied. Also, this formula had the highest release value than formula 1 (F1) that contains glycerol (2.5
g), PEG200 (0.5
g), PEG400 (0.5
g) and 0.5% dissolved drug or a commercially available gel after 24
h. FTIR revealed that there was an interaction between the polymer and the drug. The drug–polymer interaction occurring between tenoxicam and Eudragit L30D-55 seems to cause a drag effect, leading to a delay of the tenoxicam release from the Eudragit L film.
When the films were applied half an hour before the subplantar injection of carrageenan in the hind paw of Wistar rats, it was observed that formula F7 provided maximum inhibition of paw edema in rats over 24
h in contrast to both formula F1 and the marketed piroxicam gel as a reference. This was also confirmed histopathologically from skin biopsies. Thus, we show that tenoxicam can be formulated into transdermal films to sustain its release characteristics, and the polymeric composition of PEG200/PEG400 at a ratio of 1:2 and 10% PG was found to be the best choice to manufacture tenoxicam TF.
In this paper, to investigate the influence of variation in some parameters such as adhesive material and thickness, on the adhesive behavior of the self-adhesive polyethylene films, experiments and ...evaluation procedures were established and utilized. The evaluation model was provided based on the inverse problem of identifying the traction-separation behavior of self-adhesive polymeric films from their deformation configuration during T-peel test (Nase, 2016). Towards this goal, the traction-separation diagrams were extracted from the results of T-peel tests for five different self-adhesive polyethylene films. The peel test procedure was recorded with a microscopic camera, in order to extract the digital images of the deformed shape of the films within the delamination zone. The deformed lines were approximated by polynomial series based on the least square method. The traction-separation curve for each picture was calculated by inserting the polynomial equations in the mechanical evaluation models, based on the Complementary Energy Approach. The obtained traction-separation curves for each material provide several properties, can represent a clear comparison of how each parameter can influence the adhesive properties and delamination behavior. The evaluation procedure can be followed by the graphical abstract of Fig. 1.
In this paper, a direct procedure to identify interaction forces between self-adhesive flexible polymeric films is developed. High-resolution photographs of the deformed shape within and outside the ...zone of adhesive interaction are taken at different instances of the T-peel test. To describe the deformed centerline, an approximate analytical solution to the equations of the nonlinear beam theory is derived. The obtained function is the exponential sum satisfying both kinematic and static boundary conditions for the T-peel configuration. The interaction forces computed with the developed function satisfy equilibrium conditions. The procedure provides characteristics of the adhesive interaction such as the energy of adhesion, maximum force and critical opening displacement. Furthermore, the developed direct approach is applicable to generate the whole traction–separation curve.
In this paper procedures are developed to identify traction–separation curves from digital images of the deformed flexible films during peeling. T-peel tests were performed for self-adhesive ...polymeric films. High quality photographs of the deformed shape within and outside the zone of adhesive interaction were made in situ by the digital light microscope. The deformed line is approximated by a power series with coefficients computed by minimizing a least squares functional. Two approaches to identify the traction–separation curve for the given deformation line are proposed. The first one is based on the energy integral of the non-linear theory of rods and allows the direct evaluation of the adhesion force potential. The second one utilizes the complementary energy type variational equation and the Ritz method to compute the adhesion force. The accuracy of both approaches is analyzed with respect to different approximations for the deformed line and the force of interaction. The obtained traction vs. axial coordinate and the traction–separation curves provide several properties of the adhesive system including the maximum adhesion force, the length of the adhesive zone and the equilibrium position, where the adhesive force is zero while the separation is positive.
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