Effect of isopropyl myristate on the viscoelasticity and drug release of a drug-in-adhesive transdermal patch containing blonanserin

The purpose of this study was to investigate the effect of isopropyl myristate (IPM), a penetration enhancer, on the viscoelasticity and drug release of a drug-in-adhesive transdermal patch containing blonanserin. The patches were prepared with DURO-TAK (R) 87-2287 as a pressure-sensitive adhesive (PSA) containing 5% (w/w) of blonanserin and different concentrations of IPM. An in vitro release experiment was performed and the adhesive performance of the drug-in-adhesive patches with different concentrations of IPM was evaluated by a rolling ball tack test and a shear-adhesion test. The glass transition temperature (T-g) and rheological parameters of the drug-in-adhesive layers were determined to study the effect of IPM on the mechanical properties of the PSA. The results of the in vitro release experiment showed that the release rate of blonanserin increased with an increasing concentration of IPM. The rolling ball tack test and shear-adhesion test showed decreasing values with increasing IPM concentration. The results were interpreted on the basis of the IPM-induced plasticization of the PSA, as evidenced by a depression of the glass transition temperature and a decrease in the elastic modulus. In conclusion, IPM acted as a plasticizer on DURO-TAK (R) 87-2287, and it increased the release of blonanserin and affected the adhesive properties of the PSA. (C) 2016 Chinese Pharmaceutical Association and Institute of Materia Medica, Chinese Academy of Medical Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND

Oil-in-water nanoemulsions loaded with lycopene extracts encapsulated by spray drying:Formulation,characterization and optimization

Lycopene is very susceptible to degradation once released from the protective chromoplast environment.In this study,oil-in-water(O/W)nanoemulsions coupled with spray drying technology were applied for the encapsulation and stabilization of lycopene extracted from tomato waste.Tomato extract was obtained by ultrasound-assisted extraction.Nanoemulsions were prepared by a high-speed rotor stator using isopropyl myristate as the oil phase and Pluronic F-127 as the emulsifier for the aqueous external phase.The effect of emulsification process parameters was investigated.Spray drying of the produced emulsions was attempted to obtain a stabilized dry powder after the addition of a coating agent.The effect of different coating agents(maltodextrin,inulin,gum arabic,pectin,whey and polyvinylpyrrolidone),drying temperature(120-170℃),and feed flow rate(3-9 ml·min^(-1))on the obtained particles was evaluated.Results revealed that the emulsion formulation of 20/80(O/W)with 1.5%(mass fraction)of Pluronic F-127 as stabilizer in the aqueous phase resulted in a stable nanoemulsion with droplet sizes in the range of 259-276 nm with a unimodal and sharp size distribution.The extract in the nanoemulsion was well protected at room temperature with a degradation rate of lycopene of about 50%during a month of storage time.The most stable emulsions were then processed by spray drying to obtain a dry powder.Spray drying was particularly successful when using maltodextrin as a coating agent,obtaining dried spherical particles with mean diameters of(4.87±0.17)μm with a smooth surface.The possibility of dissolving the spray dried powder in order to repristinate.The original emulsion was also successfully verified.

Influence of different layers of skin on the percutaneous absorption of drugs with different lipophilicity

Objectives: To evaluate the barrier function of different skin layers in the process of percutaneous drug absorption. Methods: In vitro permeability via intact or stripped skin of 6 drugs (5-fluorouracil, theo-phylline, hydroquinone, barbital, isosorbide dinitrate and ketoprofen) with a wide span of lipophilicity were investigated in the patch dosage forms. Results: Characteristic parabolic relations was observed between the permeability (Kp, cm/h) of the drugs with different lipophilicity and their LogPc via either intact or stripped skin. However, due to the absence of the stratum corneum, increased Kp ratio for the tested drugs was proportional to their solubility in water other than their LogKp. When isopropyl myristate was used as absorption promoter of the drugs, the parabolic relationship no longer existed. For the intact skin, increase of Kp ratio of the drugs was enhanced resulting from IPM as drug's LogPc decreased. On the other hand, in the case of stripped skin, this enhancement was positively related to the solubility of the drugs in IPM. Conclusion : These data and methods present a novel approach to describe percutaneous drug absorption via damaged or diseased skin.