Dynamic Parameters in Preparing Chitosan Nanoparticles with Incorporation Method Using Novel Drug Delivery Systems

Polymeric nanoparticles with biodegradable and biocompatible polymers are good candidates in peptide drugs delivery systems. In this study, we success- fully prepared chitosan nanoparticles including salicylic acid as a model drugby emulsion cross-linking "in oil" method. The various dynamic parameters are considered, including the speed of stirrer, the duration of injecting the aqueous phase into oil phase and the condition of precipitation of particles. It is found that the optimum conditions are achieved at 2000 rpm when the aqueous phase is added within 30 min into the oil phase. According to optimum conditions the nanoparticles of chitosan (the peak of size distribution in 100 nm) were prepared and the drug content and the release behavior were estimated. The results demonstrate, that the drug content ofnanoparticles is 35% (w/w). The release behavior of nanoparticles during first 4 hour conform best to Higuchi model and thereafter up to maximum 48 h the amount of drug released is negligible

A statistical experimental design approach to evaluate the influence of various penetration enhancers on transdermal drug delivery of buprenorphine

A series of drug-in-adhesive transdermal drug delivery systems (patch) with different chemical penetration enhancers were designed to deliver drug through the skin as a site of application. The objective of our effort was to study the influence of various chemical penetration enhancers on skin permeation rate and adhesion properties of a transdermal drug delivery system using Box–Behnken experimental design. The response surface methodology based on a three-level, three-variable Box–Behnken design was used to evaluate the interactive effects on dependent variables including, the rate of skin permeation and adhesion properties, namely peel strength and tack value. Levulinic acid, lauryl alcohol, and Tween 80 were used as penetration enhancers (patch formulations, containing 0–8% of each chemical penetration enhancer). Buprenorphine was used as a model penetrant drug. The results showed that incorporation of 20% chemical penetration enhancer into the mixture led to maximum skin permeation flux of buprenorphine from abdominal rat skin while the adhesion properties decreased. Also that skin flux in presence of levulinic acid (1.594 μg/cm2 h) was higher than Tween 80 (1.473 μg/cm2 h) and lauryl alcohol (0.843 μg/cm2 h), and in mixing these enhancers together, an additional effect was observed. Moreover, it was found that each enhancer increased the tack value, while levulinic acid and lauryl alcohol improved the peel strength but Tween 80 reduced it. These findings indicated that the best chemical skin penetration enhancer for buprenorphine patch was levulinic acid. Among the designed formulations, the one which contained 12% (wt/wt) enhancers exhibited the highest efficiency

Evaluation of Adhesion Properties of Acrylic/Silicone Pressure Sensitive Adhesives Blends

In this study the blends of acrylic/silicone pressure sensitive adhesive (PSA) were prepared, and their adhesion properties and surface morphology were evaluated. For this purpose appropriate amounts of acrylic (10- 90%w/w) were added to silicone PSA to obtain visually homogeneous solution. The resulting solution was evenly applied on a polyethylene terephthalate (PET) film with final specific thicknesses (35, 65 and 110 μm) by using a film applicator. The morphological analysis was performed through scanning electron microscopy (SEM) and by the study of thermal analysis using the differential mechanical thermal analysis (DMTA) behavior of the blends, and it was found that all acrylic/silicone blends were incompatible and showed two different glass transition temperatures. By addition of silicone from 10 to 50% to acrylic/silicone blends the continuous phase is acrylic and the dispersed phase is silicone. Equally by increasing the percentage of silicone in the blends the continuous and dispersed phases were interchanged. By study of surface analysis and peel strength results it was found that surface properties are the main factors to determine peel strength values. Viscoelastic studies of the blends were shown that tack values and G" showed the same changing trend