Influence of hydroxypropyl-beta-cyclodextrin on transdermal penetration and photostability of avobenzone (original) (raw)
Related papers
European Journal of Pharmaceutics and Biopharmaceutics, 2008
The objective of the present study was to determine the effects of hydroxypropyl-b-cyclodextrin (HPCD) complexation on the transdermal penetration and photostability of a model ultraviolet A (UVA) absorber, butyl methoxydibenzoylmethane (avobenzone), and to determine the influence of complexation on in vivo photoprotection. Avobenzone-HPCD complexation was demonstrated by differential scanning calorimetry. Formulations containing 0.12 mg/ml avobenzone and up to 30% (w/w) HPCD were prepared. Transdermal penetration was conducted using a modified Franz diffusion cell apparatus. As the concentration of HPCD was increased from 0% to 20%, transdermal permeation increased. Maximum flux occurred at 20% HPCD, where sufficient cyclodextrin was present to completely solubilize all avobenzone. When the concentration of HPCD was increased to 30%, transdermal penetration decreased, suggesting the formation of an avobenzone reservoir on the skin surface. Photostability of avobenzone was investigated under 100, 250, and 500 kJ/m 2 UVA irradiation. The 30% HPCD formulation was the most photostable, followed by 20%, 10%, and 0% formulations. In vivo, the 30% HPCD formulation afforded the best photoprotection, as evidenced by the lowest extent of sunburn cell formation and edema induction. This work indicates that inclusion of HPCD in sunscreen formulations may enhance photoprotection by reducing both skin penetration and photodecomposition of UV absorbers.
International Journal of Pharmaceutics, 2004
The effects of hydroxypropyl--cyclodextrin (HP--CD) and sulfobutylether--CD (SBE7--CD) on in vitro human skin penetration and retention of the sunscreen agent butyl-methoxydibenzoylmethane (BM-DBM) were investigated. The interaction between the UV filter and the cyclodextrins was studied in water by phase-solubility analysis. Solid complexes were prepared by the co-evaporation method and characterized by 1 H NMR spectroscopy, thermal analysis and powder X-ray diffraction. Solutions containing BM-DBM free or complexed with cyclodextrins were applied to excised human skin in Franz diffusion cells and the amount of sunscreen permeated after 6 h into the stratum corneum, viable epidermis, dermis and receptor fluid was assessed by HPLC. As much as 14.10-16.78% of the applied dose of BM-DBM penetrated within the skin tissue. No sunscreen was detected in the dermis and in the receiver phase. The greater proportion (84.6-95.5%) of the absorbed UV filter was localized in the stratum corneum with no significant differences between uncomplexed or complexed BM-DBM. Notable levels (2.29% of the applied dose) of the sunscreen agent accumulated in the epidermis from the preparation containing free BM-DBM. The epidermal concentration of the UV filter was markedly reduced (0.66% of the applied dose) by complexation with SBE7--CD, whereas HP--CD had no effect. The decreased BM-DBM retention in the epidermal region achieved by SBE7--CD limits direct contact of the sunscreen and of its reactive photolytic products with the skin viable tissues.
Skin nonpenetrating sunscreens for cosmetic and pharmaceutical formulations
Clinics in Dermatology, 2008
Ultraviolet (UV) solar radiation produces harmful effects on the skin including sunburn, local 13 immunosuppression, skin photoaging, and cutaneous malignancies. Although application of sunscreens 14 is the "gold standard" for protecting the skin from UV radiation, studies have shown that currently used 15 sunscreens could cause adverse skin and systemic reactions, owing to their penetration into the viable 16 cutaneous strata and to transdermal absorption. This paper presents new nonpermeating sunscreens 17 (NPSUN) suitable for use in cosmetic and pharmaceutical products. The basic idea behind the design of 18 the new photoprotectors was to immobilize UV-absorbing moieties in the Jojoba oil chemical backbone. 19 The physicochemical characteristics of NPSUNs allow these derivatives to remain confined to the upper 20 stratum corneum where the sunscreen molecule acts, with no further clearance to deeper dermal strata or 21 systemic circulation. As an example, no permeation across the skin of methoxycinnamate-NPSUN was 22 demonstrated during 24-hour in vitro experiments, after topical application of either unformulated 23 substances or of methoxycinnamate-NPSUNs formulated in oil-in-water cream, in water-in-oil cream, or 24 in Jojoba oil. Another approach to increase the photoprotective effect against the UV radiation is 25 targeting the delivery of α tocoperol into the deeper skin layers and across the cell membranes. This is 26 necessary for optimal photoprotection and prevention of malignant processes. For this purpose, 27 ethosomal vitamin E compositions were designed, characterized, and tested. Efficient intracellular and 28 dermal accumulation of vitamin E from ethosomes was demonstrated.A good clinical strategy could be 29 the use of NPSUNs during direct UV exposure followed by the application of α-tocopherol 30 compositions after short-or long-term solar radiation. 31 33 Ultraviolet (UV) rays of the sunlight spectrum are known 34 to produce harmful effects on the skin. Adverse reactions 35 include sunburn in short-term exposure, Langerhans cells 36 depletion, and local immunosuppression caused by longer 37 UV exposure and long-term effects-cutaneous photoaging 38 and skin cancer. Ultraviolet A wavelengths penetrate deeper 39 into the skin and are primarily responsible for clinical 40 changes seen with photoaging. Shorter and 30 to 40 times 41 more energetic, ultraviolet B (290-320 nm) wavelengths 42 penetrate mostly into the epidermis and are the major cause 43 of skin photocarcinogenesis and immunosuppression. 1-3 44 Chronic exposure to solar irradiation is the primary cause 45 of extrinsic skin aging and is responsible for the main age-⁎ Corresponding author. Tel.: +972 2 6758660; fax: +972 2 6757611. 46 related alterations, such as roughness, fine wrinkles, spotty 47 protection. J Appl Cosmetol 2006;24:139-47. 341 24. Touitou E, Bergelson L, Products for preventing penetration into the 342 skin. (2002) Patent pending. 343 25. McVean M, Liebler DC. Prevention of DNA photodamage by vitamin E 344 compounds and sunscreens: roles of ultraviolet absorbance and cellular 345 uptake. Mol Carcinog 1999;24:169-76. 346 26. Lavy S. Ethosomes for enhancement of skin penetration of alpha-347 tocopherol. (2002) M.Sc. Thesis, The Hebrew University of Jerusalem, 348 Jerusalem, Israel. 349 27. Touitou E, Dayan N, Bergelson L, Godin B, Eliaz M. Ethosomes-350 novel vesicular carriers for enhanced delivery: characterization and skin 351 penetration properties. J Control Release 2000;65:403-418fs.
International journal of cosmetic science, 2011
Protection against ultraviolet (UV) radiation is the major function of sunscreen lotions and UV-protective coatings for vehicles, homes, equipment and clothing. Sunscreen formulations have been optimized to become protective over a broader spectrum of UV radiation and maintain greater photostability. They are comprised of organic and inorganic components that act as chemical and physical UV protectors, respectively. Some of the organic components are limited by their spectrum of protection and photostability. Studies using solid lipid nanoparticles, recently explored organic molecules, inorganic components and antioxidants attempt to further optimize UV protection. In this review, we examine traditional and emerging nanoparticle components and highlight novel ideas in UV protection which may provide pathways for future studies.
O R I G I N A L A R T I C L E Physicochemical study of HP-β-CD in dermal preparations
Drug Development and Industrial Pharmacy
Objective: To investigate the effect of hydroxypropyl-β-cyclodextrin (HP-β-CD) concentration on the physicochemical properties of the sunscreen agents, namely oxybenzone (Oxy), octocrylene (Oct), and ethyl-hexyl-methoxy-cinnamate (Cin), in aqueous solution and cream formulations. Methods: The inclusion complexes of sunscreen agents with hydroxypropyl-β-cyclodextrin (HP-β-CD) in aqueous solution and solid phase were studied by UV-vis spectrophotmetery, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and 13 C-NMR techniques. The photodegradation reaction of the sunscreen agents' molecules in lotion was explored using UV-vis spectrophotometry and high-performance liquid chroma-tography (HPLC). Results: The formation of the inclusion complexes was confirmed experimentally using DSC, SEM, and 13 C-NMR. The results of spectrophotometric and HPLC studies have shown that the inclu-sion complexation with HP-β-CD has the potential to enhance the photostability...
Current problems in the use of organic UV fi lters to protect skin from excessive sun exposure
2013
Abstract: The evidences of the harmful effects of skin exposure to excessive UltraViolet (UV) radiation, primarily on the development of skin cancer, have increased over the last decade. Therefore, national and international health authorities have encouraged the public to take protective sunscreens, and respectively also everyday cosmetics containing UV fi lters. In these products, a mixture of the UV fi lters, including both inorganic and organic nature, has been shown to be more effective than the individual UV fi lter. However, currently there are concerns about the safety and actual effectiveness of some UV fi lters; especially about certain UV-absorbing compounds (organic UV fi lters). Three cardinal problems are the most questionable. First, that certain UV fi lters are absorbed through the skin resulting in systemic exposure with unknown consequences. Second, that certain UV fi lters show the potential to be adversely endocrine disruptors. Third, that certain UV fi lters are...
Change of Ultraviolet Absorbance of Sunscreens by Exposure to Solar-Simulated Radiation
Journal of Investigative Dermatology, 2001
Regarding the outdoor behavior of the Caucasian population, modern sunscreens should provide high and broad-spectrum ultraviolet protection in the ultraviolet B as well as in the ultraviolet A range and should be photochemically stable for ultraviolet doses, which can be expected in solar radiation. At present an assessment of the photostability of suncare products is not a general requirement before marketing. In order to evaluate the photostability of suncare products we conducted an in vitro test and measured the spectral absorbance of 16 sunscreens before, and after exposure to increasing biologically weighted standard erythema doses (5, 12.5, 25, 50) of solar-simulated radiation. Seven of 16 suncare products showed a significant dose- and wavelength-dependent decrease of the ultraviolet A protective capacity, whereas the ability to absorb ultraviolet B was not affected. In the ultraviolet A range, the decrease of absorbance (photoinactivation), respectively, the increase of transmission was 12-48% for an ultraviolet exposure of 25 standard erythema dose. Photoinactivation started in the wavelength range between 320 and 335 nm with a maximum above 350 nm. Furthermore, our analysis showed that the behavior of suncare products was not predictable from its individual ingredients. Neither complex combinations of organic filters nor addition of inorganic filters could absolutely prevent photoinactivation. The inclusion of a single photounstable filter did not mean photoinstability of the complete suncare product. Photoinactivation of sunscreens appears to be an underestimated hazard to the skin, first, by formation of free radicals, second, by increased ultraviolet A transmission.
In vitro photostability and photoprotection studies of a novel ‘multi-active' UV-absorber
Free Radical Biology and Medicine, 2008
This paper reports on the synthesis and properties of a new UV-absorber (OC-NO) based on the most popular UV filter worldwide, ethylhexyl methoxycinnamate (OMC) in which the methoxy group has been replaced with a pyrrolidine nitroxide bearing antioxidant activity. This sunscreen active has therefore both UVabsorbing and antioxidant properties which could ideally address both the UV-B and UV-A skin photodamage. For broad-spectrum coverage, the combinations of OC-NO with two commonly used UV-A absorbers (BMDBM and DHHB) were also studied. The results obtained reveal that OC-NO: (a) is as photostable as OMC after UV-A exposure; (b) acts as free radical scavenger as demonstrated by EPR and chemical studies; (c) reduces UV-A and UV-A+BMDBM induced lipid peroxidation in liposomes and cells, measured as reduced TBARS levels and increased C11-BODIPY red fluorescence, respectively; (d) has comparable antioxidant activity to that of vitamin E and BHT commonly used in skin care formulations; (e) is non-cytotoxic to human skin fibroblasts as assessed with the MTT assay when exposed to increasing doses of UV-A; and (f) OC-NO+ DHHB is a promising, photostable broad spectrum UV-filter combination that concomitantly reduces UVinduced free radical damage. These results suggest that nitroxide/antioxidant-based UV-absorbers may pave the way for the utilization of 'multi-active' ingredients in sunscreens thereby reducing the number of ingredients in these formulations.