monooctanoin and isopropyl-myristate

Cutaneous delivery of combinations of antioxidants offers the possibility of enhanced protection against UV-radiation. In this study, we investigated the potential of sugar-based microemulsions containing monoglycerides to promote simultaneous cutaneous delivery of lycopene and ascorbic acid, and increase tissue antioxidant activity. Lycopene and ascorbic acid were incorporated (0.04% and 0.2% (w/w), respectively) in decylglucoside-based microemulsions containing isopropyl myristate mixed with monocaprylin (ME-MC), monolaurin (ME-ML) or monoolein (ME-MO) as oil phase. The microemulsions increased lycopene delivery into porcine ear skin by 3.3- to 8-fold compared to a drug solution. The effect of microemulsions on ascorbic acid cutaneous delivery was more modest (1.5-3-fold), and associated with an approximately 2-fold increase in transdermal delivery. According to their penetration-enhancing ability, the microemulsions were ranked ME-MC>ME-MO>ME-ML. This superiority of ME-MC coincided with a stronger effect in decreasing skin electrical resistance. After 18 h of treatment, the viability of bioengineered skin treated with ME-MC was 2.2-times higher compared to Triton-X100 (moderate irritant), demonstrating that ME-MC is less cytotoxic. Skin treatment with ME-MC containing both antioxidants increased the tissue antioxidant activity by 10.2-fold, but no synergism between the antioxidants was observed.

Topics: Administration, Cutaneous; Animals; Antioxidants; Ascorbic Acid; Caprylates; Carotenoids; Drug Delivery Systems; Emulsions; Excipients; Glucosides; Glycerides; Laurates; Lycopene; Monoglycerides; Myristates; Skin; Skin Absorption; Swine

The aim of this investigation was to assess the applicability of lipid bilayer alteration using a combination of isopropyl myristate (IPM) and glyceryl monocaprylate (GEFA-C(8)) to the enhancement of pentazocine (PTZ) permeation through hairless mouse skin. The skin permeability of PTZ was enhanced by increasing the concentration of GEFA-C(8) up to 10% w/w in combination with IPM. Attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) and small angle X-ray diffraction (SAXD) were carried out to analyze the effects of these enhancers on the biophysical properties of the stratum corneum (SC) of the skin, and on the permeation of PTZ. ATR-FTIR studies revealed that IPM/GEFA-C(8) induced higher CH(2) stretching frequencies of SC lipids than IPM alone. SAXD showed the disappearance of long lamellar diffraction of SC lipids with IPM/GEFA-C(8), resulting in a complete loss of order of the SC lipid bilayers. When 1,1'-dioctadecyl-3,3,3',3'-tetramethyl-indocarbocyanine perchlorate (DiI), a hydrophobic fluorescence probe, was applied in IPM alone, the amount of DiI which penetrated into the intercellular space of the SC was very low, but this was markedly increased when DiI was applied in IPM/GEFA-C(8). These results indicate that the synergistic effects of IPM and GEFA-C(8) enhance transdermal permeation of PTZ by disrupting SC lipids.

Topics: Administration, Cutaneous; Animals; Caprylates; Drug Synergism; Glycerides; Male; Mice; Mice, Hairless; Myristates; Pentazocine; Skin Absorption