Physicochemical characterization of tretinoin tocoferil emulsion and povidone-iodine sugar ointment blend developed for improved regulation of wound moisture.

Maintenance of proper moisture and regulation of infection are simultaneously required to promote healing of pressure ulcers. Continuous use of water-rich ointment may often lead to excess moisture and induce edematous granulation tissue. Use of water soluble ointment may excessively absorb exudates and induce dry granulation tissue. Selection of appropriate topical ointment is desired to avoid worse clinical outcomes. For adjustment of wound moisture a novel blended ointment (tretinoin tocoferil-povidone-iodine (TR-PI)) was developed consisting of emulsion base, tretinoin tocoferil oil-in-water (o/w) emulsion (TR-cream), and sugar base, povidone-iodine and sugar (PI-sugar). For the characterization of TR-PI water absorption was tested using Franz diffusion cell with cellulose membrane. For rheological characteristics spreadability was tested using spread meter and yield value was calculated. Iodine permeation was tested using a permeation cell with silicon membrane. Water absorption rate constant of TR-PI with combination ratio of PI-sugar at 75% (TR-PI75, 18.5 mg cm(-2) min(-0.5)) was equivalent to that of TR-cream alone (16.4 mg cm(-2) min(-0.5)). The yield value of TR-PI75 (26.1 Pa) exhibited intermediate values as compared to those of TR-PI with combination ratio of PI-sugar at 50% (11.3 Pa) and TR-cream alone (46.8 Pa). The amount of released free-iodine from TR-PI75 was similar to that released from PI-sugar alone. TR-PI75 may have superior performance in keeping the moist environment in wounds and in preventing infection. TR-PI75 can be used to promote formation of favorable granulation tissue in pressure ulcers with moderate exudates.