methylcellulose and nonivamide

Film forming emulsions containing Eudragit® NE 30D (NE) and/or Eudragit® RS 30D (RS) were developed and investigated. The influences of surfactant (polysorbate 80), thickeners (hydroxypropylmethylcellulose (HPMC), polyvinylpyrrolidone (PVP), polyvinylalcohol (PVA)) and varying compositions of NE and RS on glass transition temperature, mechanical properties and water resistance of free films were investigated. Elongation was found to increase with increasing NE fraction or addition of polysorbate 80 and to decrease with the addition of PVP. Adhesion to polycarbonate was generally higher than to glass. Adhesion to glass and polycarbonate was found to be influenced by NE/RS ratio, choice of thickener and addition of surfactant. An increase in RS led to stronger adherence to glass and to higher water resistance. Desired properties were obtained from films containing PVA, polysorbate 80 and 0-40% NE. These formulations were used in in vitro release and permeation experiments. In vitro release of nonivamide was found to rise with increasing amount of NE in the formulation. Permeation through pig ear skin was found to be independent of NE-ratio but was clearly slower than from a standard formulation.

Topics: Acrylic Resins; Administration, Cutaneous; Animals; Capsaicin; Chemistry, Pharmaceutical; Delayed-Action Preparations; Emulsions; Glass; Hypromellose Derivatives; Methacrylates; Methylcellulose; Permeability; Polycarboxylate Cement; Polymers; Polysorbates; Polyvinyl Alcohol; Povidone; Skin; Skin Cream; Surface-Active Agents; Swine; Transition Temperature

The aim of this study was to investigate the transdermal iontophoresis of a newly designed capsaicin derivative, sodium nonivamide propionate (SNP). The iontophoretic permeation of SNP from various pH buffers increased following the decrease of pH values. This trend was consistent with that of sodium nonivamide acetate (SNA) which is another synthetic analogue of capsaicin. However, the iontophoretic permeability of SNP was much lower than that of SNA. SNP was also delivered iontophoretically from hydrogel formulations. It is suggested that ionizable polymers should be avoided for iontophoretic delivery to maintain good penetration capacity of drugs. Both nonionic cellulose polymers of methylcellulose (MC) and hydroxypropyl methylcellulose (HPMC) showed higher iontophoretic flux for SNP than the others did. Furthermore, the flux of SNP leveled off with an increase in the amount of polymers in hydrogel, indicating that the viscosity of vehicles plays an important role in the permeation of SNP. Comparing the various iontophoretic application modes, the discontinuous on/off cyclic mode showed higher penetration capacity than did the continuous mode although they possessed the same electrical energy. Moreover, the desorption time of SNP from skin was approximately 20 min which was longer than that of SNA.

Topics: Administration, Cutaneous; Animals; Capsaicin; Cellulose; Enzyme Inhibitors; Hydrogels; Hydrogen-Ion Concentration; Iontophoresis; Methylcellulose; Rats; Rats, Wistar; Skin Absorption