Non-invasive depth profile imaging of the stratum corneum using confocal Raman microscopy: First insights into the method

Ashtikar, Mukul; Matthäus, Christian; Schmitt, Michael; Krafft, Christoph; Fahr, Alfred; Popp, Jürgen

doi:10.1016/j.ejps.2013.05.030

Cited by 51 publications

(54 citation statements)

References 46 publications

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“…CRM measurements were employed to evaluate the skin penetration depth of the sunscreens into the porcine ear skin based on their chemical composition, which means that a Raman spectrum is highly molecule specific [29,38,39]. According to our data (Fig.…”

Section: Discussionmentioning

confidence: 99%

Radical-Scavenging Activity of a Sunscreen Enriched by Antioxidants Providing Protection in the Whole Solar Spectral Range

Souza

Campos²,

Schanzer³

et al. 2017

Skin Pharmacol Physiol

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Background/Aim: The main reason for extrinsic skin aging is the negative action of free radicals. The formation of free radicals in the skin has been associated with ultraviolet (UV) exposure and also to visible (VIS) and near-infrared (NIR) irradiations. The aim of the present study was to evaluate the efficacy of a sunscreen in the whole solar range. Methods: The radical-scavenging activity of a sunscreen in the UV, VIS, and NIR ranges was evaluated using electron paramagnetic resonance spectroscopy. Ex vivo penetration profiles were determined using confocal Raman microscopy on porcine ear skin at different time points after application. Results: Compared to the untreated skin, the sunscreen decreased the skin radical formation in the UV and VIS regions. Additional protection in the VIS and NIR ranges was observed for the sunscreen containing antioxidants (AO). The penetration depth of the cream was less than 11.2 ± 3.0 µm for all time points. Conclusion: A sunscreen containing AO improved the photoprotection in the VIS and NIR ranges. The sunscreen was retained in the stratum corneum. Therefore, these results show the possibility of the development of effective and safer sunscreen products.

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Section: Discussionmentioning

confidence: 99%

Radical-Scavenging Activity of a Sunscreen Enriched by Antioxidants Providing Protection in the Whole Solar Spectral Range

Souza

Campos²,

Schanzer³

et al. 2017

Skin Pharmacol Physiol

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Section: Preclinical Pharmacokinetic Evaluationsmentioning

confidence: 99%

“…CLSM is also used to diagnose common benign skin lesions and to characterize malignant lesions. Applications of CLSM include the characterization of keratinization and pigmentation disorders (Caspers et al, 2001;Ashtikar et al, 2013;Franzen, Anderski, Windbergs, 2015).…”

Section: Confocal Laser Scanning Microscopymentioning

confidence: 99%

“…Transepidermal water loss from the skin or electrical conductivity measurements across the skin are useful for detection of skin damage, physical injury, or pathological conditions. The toxicity of the drug or formulation in the skin also may be investigated (Ashtikar et al, 2013;Pažoureková et al, 2013;Oliveira et al, 2014;Guth et al, 2015).Pharmacokinetic evaluations of a transdermal delivery system are essential to determine the in vivo behavior of the drug administered by the skin route because in vitro studies cannot reproduce the complexity of biological systems, such as metabolism, distribution, and elimination. The contribution of skin absorption by different pathways, such as the epidermis or skin appendages, is also important and may be characterized during the preclinical pharmacokinetic studies (Godin, Touitou, 2007;Farahmand, Maibach, 2009).…”

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confidence: 99%

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Evaluation of skin absorption of drugs from topical and transdermal formulations

Ruela

Perissinato

Lino

et al. 2016

Braz. J. Pharm. Sci.

197

135

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The skin barrier function has been attributed to the stratum corneum and represents a major challenge in clinical practice pertaining to cutaneous administration of drugs. Despite this, a large number of bioactive compounds have been successfully administered via cutaneous administration because of advances in the design of topical and transdermal formulations. In vitro and in vivo evaluations of these novel drug delivery systems are necessary to characterize their quality and efficacy. This review covers the most well-known methods for assessing the cutaneous absorption of drugs as an auxiliary tool for pharmaceutical formulation scientists in the design of drug delivery systems. In vitro methods as skin permeation assays using Franz-type diffusion cells, cutaneous retention and tape-stripping methods to study the cutaneous penetration of drugs, and in vivo evaluations as pre-clinical pharmacokinetic studies in animal models are discussed. Alternative approaches to cutaneous microdialysis are also covered. Recent advances in research on skin absorption of drugs and the effect of skin absorption enhancers, as investigated using confocal laser scanning microscopy, Raman confocal microscopy, and attenuated total reflectance Fourier-transform infrared spectroscopy, are reviewed. Uniterms:Skin absorption/effects/study. Skin absorption/topical formulations. Skin absorption/ transdermal formulations. Skin absorptions/enhancers. INTRODUCTIONTopical and transdermal drug delivery systems have shown significant advantages in clinical practice for drug targeting to the action site in the body; this has reduced the systemic side effects. The administration of drugs by through the skin is also performed to achieve controlled or prolonged drug delivery, and this route can be explored as an alternative to the oral route. The oral route shows some limitations for drugs with irregular absorption in the gastrointestinal tract and low bioavailability and for drugs with increased first pass metabolism and short plasma halflife times (Barry, 2001;Wokovich et al., 2006;Prausnitz, Langer, 2009;Alexander et al., 2012).Many drug products applied to the skin surface may penetrate to some extent into the skin layers, where their effects are expected. This is the case for topical formulations for treatment of skin disorders such as acne and cutaneous inflammatory diseases that include dermatitis, erythematous lupus, and psoriasis. On the other hand, transdermal formulations release drugs that permeate through the skin and enter the systemic circulation. Transdermal therapy must ensure that significant concentrations of the drug are absorbed to reach effective plasma concentrations. Permeation of drugs is targeted in some cases to body regions close to the action site, where a regional effect is expected, e.g., in the muscles, blood vessels, and articulations. In this way, the term "cutaneous absorption" is properly used to characterize the sum of the amounts of drug that penetrate and permeate the skin (Barry, 2001;El Maghraby, Barry;Willi...

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“…Confocal Raman microspectroscopy (CRM) is increasingly used to determine penetration profiles of xenobiotics in the skin due to the fact that it is a non-destructive method and only minimal sample preparation is needed [1,2,3,4,5,6,7,8,9,10,11,12]. Furthermore, it can also be performed in a non-invasive manner and therefore enables in vivo measurements.…”

Section: Introductionmentioning

confidence: 99%

How Confocal Is Confocal Raman Microspectroscopy on the Skin? Impact of Microscope Configuration and Sample Preparation on Penetration Depth Profiles

Lunter¹

2016

Skin Pharmacol Physiol

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Background/Aims: The aim of the study was to elucidate the effect of sample preparation and microscope configuration on the results of confocal Raman microspectroscopic evaluation of the penetration of a pharmaceutical active into the skin (depth profiling). Methods: Pig ear skin and a hydrophilic formulation containing procaine HCl were used as a model system. The formulation was either left on the skin during the measurement, or was wiped off or washed off prior to the analysis. The microscope configuration was varied with respect to objectives and pinholes used. Results: Sample preparation and microscope configuration had a tremendous effect on the results of depth profiling. Regarding sample preparation, the best results could be observed when the formulation was washed off the skin prior to the analysis. Concerning microscope configuration, the use of a 40 × 0.6 numerical aperture (NA) objective in combination with a 25-µm pinhole or a 100 × 1.25 NA objective in combination with a 50-µm pinhole was found to be advantageous. Conclusion: Complete removal of the sample from the skin before the analysis was found to be crucial. A thorough analysis of the suitability of the chosen microscope configuration should be performed before acquiring concentration depth profiles.

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Non-invasive depth profile imaging of the stratum corneum using confocal Raman microscopy: First insights into the method

Cited by 51 publications

References 46 publications

Radical-Scavenging Activity of a Sunscreen Enriched by Antioxidants Providing Protection in the Whole Solar Spectral Range

Radical-Scavenging Activity of a Sunscreen Enriched by Antioxidants Providing Protection in the Whole Solar Spectral Range

Evaluation of skin absorption of drugs from topical and transdermal formulations

How Confocal Is Confocal Raman Microspectroscopy on the Skin? Impact of Microscope Configuration and Sample Preparation on Penetration Depth Profiles

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