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1.
Skin Pharmacol Physiol ; 27(2): 82-9, 2014.
Article in English | MEDLINE | ID: mdl-24052131

ABSTRACT

Sunscreens are a key pillar of the multimodal protection strategy against short- and long-term impacts of intermittent and continuous UV exposure. Hitherto, an unanswered part of current scientific discourse is the question whether a cosmetic pretreatment has an impact on distribution and adhesiveness of sunscreens on the skin and therefore affects UV protection. In order to evaluate the homogeneity of sunscreen filter distribution, water resistance as a parameter of adhesiveness and effective UV protection of sunscreens after a pretreatment with cream or lotion was investigated in 18 volunteers who were examined before and after swimming, using the established combination of the tape stripping procedure and UV/VIS spectroscopy. It was shown that a cosmetic skin pretreatment affects neither filter homogeneity nor effective UV protection prior to water contact. However, compared to nonpretreated skin, a considerable loss of water resistance is caused. Therefore, using a cream or lotion before application of sunscreens is not to be recommended.


Subject(s)
Skin Cream/administration & dosage , Sunscreening Agents/administration & dosage , Adhesiveness , Adolescent , Adult , Female , Humans , Male , Middle Aged , Skin Absorption , Skin Cream/chemistry , Sunscreening Agents/chemistry , Water/chemistry , Young Adult
2.
Skin Pharmacol Physiol ; 26(1): 30-5, 2013.
Article in English | MEDLINE | ID: mdl-23128400

ABSTRACT

The objective of the present investigation was to examine the utilization of optical and spectroscopic methods for the noninvasive characterization of Anthelios XL Fluide Extreme (SPF 50+), an exemplary sunscreen, concerning its homogeneity of distribution on the skin, its spectroscopic properties and its overall protective efficacy. The homogeneity of the distribution of the sunscreen on the skin was investigated with a multiphoton tomography microscope. Additionally, the sum transmission spectrum was determined using tape stripping and spectroscopic measurements. The results revealed a very homogeneous distribution of the sunscreen on the skin surface and also in the deep furrows. The sum transmission spectrum reflects a high protective efficacy of the sunscreen in both the UVA and UVB ranges. The sunscreen Anthelios XL Fluide Extreme (SPF 50+) generates a comfortable feeling on the skin and can be easily distributed. The presented optical methods have been shown to be suitable to investigate the overall protective efficacy of sunscreen products objectively, noninvasively and quickly.


Subject(s)
Skin/metabolism , Sunscreening Agents/pharmacokinetics , Adult , Humans , Middle Aged , Sensation , Skin Absorption , Spectrum Analysis , Tomography , Treatment Outcome
3.
Int J Cosmet Sci ; 34(6): 551-9, 2012 Dec.
Article in English | MEDLINE | ID: mdl-22957937

ABSTRACT

The efficacy of a drug is characterized by its action mechanism and its ability to pass the skin barrier. In this article, different methods are discussed, which permit this penetration process to be analysed non-invasively. Providing qualitative and quantitative information, tape stripping is one of the oldest procedures for penetration studies. Although single cell layers of corneocytes are removed from the skin surface, this procedure is considered as non-invasive and is applicable exclusively to the stratum corneum. Recently, optical and spectroscopic methods have been used to investigate the penetration process. Fluorescence-labelled drugs can be easily detected in the skin by laser scanning microscopy. This method has the disadvantage that the dye labelling changes the molecular structures of the drug and consequently might influence the penetration properties. The penetration process of non-fluorescent substances can be analysed by Raman spectroscopy, electron paramagnetic resonance, CARS and multiphoton microscopic measurements. Using these methods, the concentration of the topically applied formulations in different depths of the stratum corneum can be detected by moving the laser focus from the skin surface deeper into the stratum corneum. The advantages and disadvantages of these methods will be discussed in this article.


Subject(s)
Skin Absorption , Administration, Topical , Electron Spin Resonance Spectroscopy , Fluorescent Dyes , Humans , Microscopy/methods , Spectrum Analysis, Raman
4.
Skin Pharmacol Physiol ; 25(3): 118-23, 2012.
Article in English | MEDLINE | ID: mdl-22343548

ABSTRACT

The inhomogeneous distribution of topically applied substances due to decisive differences in the skin structure (furrows and wrinkles) affects the efficacy of cosmetic products, in particular sunscreens. The combination of tape stripping and optical spectroscopy results in absorption data, which reflect ex vivo the inhomogeneity of the in vivo distribution of topically applied substances. Based on these data, a factor of inhomogeneity is defined describing the individual distribution of formulations on the skin surface of volunteers. Thus, the influence of different skin surface structures and the influence of different formulations on the distribution of the topically applied substances can be determined. Analyzing the inhomogeneity data on 6 volunteers (5 sunscreens per volunteer), it was found that the influence on the distribution of sunscreens caused by the formulation was higher than the inhomogeneity originating from the differences in the skin surface structure of the volunteers. The method is well suited to characterize, for example, sunscreens and antiaging creams in the process of development, as well as for the evaluation of the final products.


Subject(s)
Skin Absorption , Skin/metabolism , Sunscreening Agents/administration & dosage , Sunscreening Agents/metabolism , Administration, Cutaneous , Adult , Chemistry, Pharmaceutical , Emulsions , Germany , Humans , Microscopy, Confocal , Skin/anatomy & histology , Spectrophotometry, Ultraviolet , Sunscreening Agents/chemistry , Young Adult
5.
Skin Pharmacol Physiol ; 24(5): 231-7, 2011.
Article in English | MEDLINE | ID: mdl-21455016

ABSTRACT

In the case of topically applied substances, usually both lateral spreading and competitive penetration into the skin occur in parallel. In the present study, the pathways of lateral spreading were studied quantitatively and visually. The local distribution and lateral spreading of the UV filter substance butyl methoxydibenzoylmethane applied in an o/w emulsion was studied on the forearm and the back. The tape stripping procedure was used to determine the recovery rates inside and outside the area of application. The skin characteristics of transepidermal water loss, pH value, hydration of the stratum corneum and sebum rate were determined at both anatomic sites. Photography and laser scanning microscopy were used to visually investigate the lateral spreading of topically applied dyes. On the back, a preferred direction of lateral spreading parallel to the body axis was observed. This result was caused by differences in the network of furrows. The furrows functioned as a pathway for lateral spreading, whereas the follicles formed a reservoir for the topically applied substance.


Subject(s)
Skin Absorption , Sunscreening Agents/pharmacokinetics , Administration, Cutaneous , Adult , Alkanes/administration & dosage , Alkanes/analysis , Back , Chalcones/administration & dosage , Chalcones/analysis , Emulsions , Female , Forearm , Humans , Hydrogen-Ion Concentration , Male , Propiophenones , Skin/metabolism , Spectrum Analysis , Sunscreening Agents/administration & dosage , Surgical Tape , Water Loss, Insensible , Young Adult
6.
Eur J Pharm Biopharm ; 72(2): 317-23, 2009 Jun.
Article in English | MEDLINE | ID: mdl-18775778

ABSTRACT

Tape stripping is a simple and efficient method for the assessment of quality and efficacy of cosmetical and dermatological formulations. After topical application and penetration of formulations, the cell layers of the stratum corneum are successively removed from the same skin area using adhesive films. The tape strips contain the amount of corneocytes and the corresponding amount of the penetrated formulation, which can be determined by classical analytical chemical methods. Different formulations can strongly influence the amount of stratum corneum removed with every tape strip. Therefore, it is essential for the comparison of the penetration of different formulations that the amount of formulation detected on the single tape strip is not related to the tape strip number as a relative measure of the penetration depths, but to their standardized real position in the stratum corneum. Therefore, different methods are reported for the determination of the amount of stratum corneum removed with every tape strip. The tape stripping method in its standardized form is well-suited to determine the dermatopharmacokinetics of topically applied substances. Additionally, the method can be used to obtain information about the homogeneity and the distribution of formulations on the skin and in the stratum corneum. This is used, e.g., for the determination of the homogeneity of the distribution and the ex vivo determination of a universal sun protection factor (USPF) characterizing the efficacy of sunscreens.


Subject(s)
Cosmetics , Dermatologic Agents , Surgical Tape , Cosmetics/pharmacokinetics , Dermatologic Agents/pharmacokinetics , Humans , Skin/metabolism
7.
J Biomed Opt ; 11(5): 054026, 2006.
Article in English | MEDLINE | ID: mdl-17092175

ABSTRACT

Tape stripping is a standard measuring method for the investigation of the dermatopharmacokinetics of topically applied substances using adhesive films. These tape strips are successively applied and removed from the skin after application and penetration of topically applied substances. Thus, layers of corneocytes and some amount of topical applied substances are removed. The amount of substances and the amount of stratum corneum removed with a single tape strip has to be determined for the calculation of the penetration profile. The topically applied substances removed from the skin can be determined by classical analytical methods like high-pressure liquid chromatography, mass spectroscopy, and spectroscopic measurements. The amount of corneocytes on the tape strips can be easily detected by their pseudoabsorption. In the present paper, an easy and cheap corneocyte density analyzer is presented that is based on a slide projector. Comparing the results of the measurements obtained by the corneocyte density analyzer and by uv-visible spectrometry, identical results were obtained.


Subject(s)
Cell Count/instrumentation , Clobetasol/administration & dosage , Clobetasol/pharmacokinetics , Keratinocytes/cytology , Keratinocytes/metabolism , Skin Absorption/physiology , Surgical Tape , Administration, Topical , Adult , Cell Count/methods , Equipment Design , Equipment Failure Analysis , Humans , Optics and Photonics/instrumentation , Photometry/instrumentation , Photometry/methods
8.
J Neural Transm (Vienna) ; 113(3): 387-97, 2006 Mar.
Article in English | MEDLINE | ID: mdl-15997416

ABSTRACT

OBJECTIVE: The aim of this study was to examine concentrations of levomepromazine and its metabolite desmethyl-levomepromazine in different regions of human brain and in relationship to drug-free time. METHODS: Drug concentrations were measured in up to 43 regions of 5 postmortem human brains of patients previously treated with levomepromazine. To enable statistical comparison across brain regions several smaller brain areas were put together to form larger brain areas (cortex cerebri, limbic system, cerebellum, basal ganglia, thalamus). Mean values of drug concentrations in these larger brain areas were used in a repeated measurement ANOVA to analyze for region specific distribution. The elimination half-life in brain tissue was estimated with a NONMEM population kinetic analysis using the mean value of all brain regions of an individual case. RESULTS: Levomepromazine and desmethyl-levomepromazine appear to accumulate in human brain tissue relative to blood. Mean concentrations differed largely between individual brains, in part due to differences in dose of drug, duration of treatment and drug-free time before death. There was an apparent region-specific difference in levomepromazine concentrations with highest values in the basal ganglia (mean 316 ng/g) and lowest values in the cortex cerebri (mean 209 ng/g). The elimination half-life from brain tissue is longer than from blood and was calculated to be about one week. Similar results were obtained with desmethyl-levomepromazine. CONCLUSIONS: Levomepromazine shows a region-specific distribution in the human brain with highest values in the basal ganglia. This might be the consequence of low expression of the metabolic enzyme Cyp2D6 in the basal ganglia. If this finding is true also for other neuroleptic drugs it might increase our understanding of preferential toxicity of neuroleptic drugs against basal ganglia structures and higher volumes of basal ganglia of neuroleptic-treated patients. Furthermore, patients exposed to levomepromazine cannot be considered to be free of residual effects of the drug for a number of weeks after withdrawal.


Subject(s)
Antipsychotic Agents/pharmacokinetics , Brain/drug effects , Methotrimeprazine/pharmacokinetics , Aged , Aged, 80 and over , Antipsychotic Agents/metabolism , Basal Ganglia/drug effects , Basal Ganglia/metabolism , Brain/anatomy & histology , Brain/metabolism , Cytochrome P-450 CYP2D6/metabolism , Female , Humans , Male , Metabolic Clearance Rate/drug effects , Metabolic Clearance Rate/physiology , Methotrimeprazine/metabolism , Molecular Structure
9.
Skin Pharmacol Physiol ; 18(4): 180-5, 2005.
Article in English | MEDLINE | ID: mdl-15908758

ABSTRACT

The objective and quantitative application of tape stripping in pharmaceutics and dermatopharmacokinetics requires the determination of the exact position of each removed tape strip inside the stratum corneum (SC) and/or the determination of the relative SC thickness. In this study, transepidermal water loss (TEWL) and the optical spectroscopic data of the corneocytes were measured simultaneously during the complete removal of the SC by tape stripping. The spectroscopic data quantitatively reflect the amount of corneocytes removed by the individual tape strips, whereas TEWL and 1/TEWL are not sensitive enough to measure the relatively small changes in the SC thickness realized by the removal of the individual strips. The relative SC thickness can be determined directly by the spectroscopic data, while the 1/TEWL values require a second independent method. The results demonstrate the importance of tape stripping characterizing the behaviour of topically applied substances.


Subject(s)
Adhesives , Body Water/metabolism , Epidermal Cells , Epidermis/metabolism , Specimen Handling/methods , Adult , Cell Count , Humans , Middle Aged , Skin Absorption , Spectrophotometry, Ultraviolet , Water
10.
Skin Res Technol ; 11(2): 91-6, 2005 May.
Article in English | MEDLINE | ID: mdl-15807805

ABSTRACT

BACKGROUND/PURPOSE: The tape stripping procedure is a suitable minimal invasive tool to study, e.g. the penetration and dermatopharmacokinetics of topically applied substances. In the present study, this procedure was used to remove the stratum corneum (SC) completely and to study the penetration of the UVA filter substance butyl methoxydibenzoylmethane after application in two different vehicles. METHODS: The amount of corneocytes removed by each tape strip from the flexor forearm of human volunteers was determined via their pseudo-absorption. In a second part, the penetration profiles of a UVA filter substance applied in two different vehicles were determined following the developed standard protocol using the tape stripping procedure in combination with UV/VIS spectroscopy. RESULTS: The amount of corneocytes removed by each tape strip was related to the number of tape strips used for removal. Mean values with a deviation of less than 20% concerning the relative amount of SC removed by a constant number of tape strips were obtained. For instance, a relative amount of 66 +/- 12% was removed with the first 20 tape strips, while nearly the complete SC (95 +/- 3%) was removed using 50 tape strips. In addition, these results were used to estimate the relative SC amounts removed, studying the penetration of the UVA filter substance after application in two different vehicles. No significant differences between the distributions of the UV filter substance applied in both emulsions were obtained (P > 0.05). CONCLUSIONS: The reported procedure for the estimation of the removed SC amount provides the possibility to avoid the complete removal of the SC and to compare the penetration characteristics obtained for different volunteers and different products in relation to the relative horny layer profile.


Subject(s)
Bandages , Colorimetry/instrumentation , Epidermis/physiology , Gene Expression Profiling/instrumentation , Proteins/analysis , Proteins/metabolism , Reagent Strips , Specimen Handling/methods , Adhesiveness , Adolescent , Adult , Aged , Cell Adhesion , Cell Count/methods , Colorimetry/methods , Gene Expression Profiling/methods , Humans , Male
11.
Skin Pharmacol Physiol ; 18(2): 75-80, 2005.
Article in English | MEDLINE | ID: mdl-15767768

ABSTRACT

Investigations on the stratum corneum (SC) reservoir for topically applied substances are of importance in dermatologic science in order to assess the pharmacokinetics of these substances. In the present study, an in vivo method was developed to determine the SC reservoir quantitatively and to investigate the temporal behavior of this reservoir. Therefore, increasing amounts of an oil-in-water emulsion (o/w emulsion) containing 4% of a chemical UV filter were topically applied onto the flexor forearms of 5 healthy volunteers. The saturation of the SC reservoir was determined utilizing the tape stripping technique 1 and 6 h after application. The capacity of the SC reservoir for the o/w emulsion was found to be approximately 2.7 mg/cm(2). Furthermore, a correlation of the capacity of the SC with transepidermal water loss was observed. Extending the time between the topical application and SC removal did not affect the distribution or the recovery rate of the UV filter in the SC. The results indicate that the reservoir of the SC is limited. This is reflected by the saturation level, which depends on the individual volunteer and, presumably, the topically applied substances and formulations used. The results show that the method developed is suited to quantitatively determine in vivo the SC reservoir for topically applied substances.


Subject(s)
Administration, Topical , Epidermis/physiology , Skin Absorption/physiology , Adult , Animals , Dermatology/methods , Dermatology/trends , Drug Evaluation/methods , Drug Evaluation, Preclinical/methods , Emulsions/chemistry , Emulsions/pharmacology , Epidermis/drug effects , Female , Humans , Male , Skin Absorption/drug effects , Species Specificity , Specimen Handling/methods , Sunscreening Agents/administration & dosage , Sunscreening Agents/analysis , Sunscreening Agents/metabolism , Time Factors , Ultraviolet Rays/adverse effects
12.
Pharmacopsychiatry ; 37(2): 43-5, 2004 Mar.
Article in English | MEDLINE | ID: mdl-15048609

ABSTRACT

INTRODUCTION: Hypersalivation is known as a frequent, disturbing, and socially stigmatizing side effect of therapy with the atypical antipsychotic clozapine. It has been shown that the addition of the anticholinergic pirenzepine is able to reduce clozapine-induced hypersalivation, probably by blocking M4-receptors. Nevertheless, a pharmacokinetic interaction between both compounds cannot be excluded. METHODS: In this pilot study, 29 schizophrenic patients (ICD-10; 51.7 % female; age: 36.7 +/- 8.7 years [mean +/- SD]) were included. Serum concentrations of clozapine and its pharmacologically active metabolite N-desmethylclozapine were determined under steady-state conditions by automated HPLC with UV detection before and after addition of pirenzepine for 3 days. RESULTS: Significantly fewer patients reported hypersalivation after addition of pirenzepine (69 % vs. 34.5 %, P = 0.002). No significant differences of clozapine and N-desmethylclozapine serum levels before (329 +/- 181 ng/ml and 218.0 +/- 123.4 ng/ml, respectively) and 3 days after (336 +/- 215 ng/ml and 235.9 +/- 164.4 ng/ml, respectively) addition of pirenzepine were found. In three patients, however, clozapine serum levels increased; this was probably unrelated to pirenzepine. CONCLUSION: In conclusion, treatment of clozapine-induced hypersalivation with pirenzepine is a recommendable combination with low risk of additional side effects.


Subject(s)
Clozapine/analogs & derivatives , Clozapine/adverse effects , Pirenzepine/therapeutic use , Sialorrhea/drug therapy , Adult , Antipsychotic Agents/adverse effects , Chromatography, High Pressure Liquid/methods , Clozapine/blood , Cross-Over Studies , Dose-Response Relationship, Drug , Drug Interactions , Female , Humans , Male , Middle Aged , Muscarinic Antagonists/therapeutic use , Pilot Projects , Schizophrenia/blood , Schizophrenia/drug therapy , Sialorrhea/chemically induced , Spectrophotometry, Ultraviolet/methods
13.
Skin Pharmacol Physiol ; 17(1): 17-22, 2004.
Article in English | MEDLINE | ID: mdl-14755123

ABSTRACT

The lateral spreading of topically applied substances is a competitive process to the penetration into the stratum corneum (SC). The penetration of topically applied UV filter substances into the human SC and the lateral spreading were investigated in vivo. Tape stripping in combination with spectroscopic measurements was used to study both processes of two UV filter substances. The concentration of both UV filters was determined inside and outside the application area by varying the application and tape stripping protocol. A spreading of the topically applied substances from the treated to the untreated areas was observed, which caused a concentration gradient. This lateral spreading depends on the time between application and tape stripping and the size of the treated skin area. Significant amounts of topically applied substances were found adjoining the application area, due to the lateral spreading which takes place on the skin surface. In general, the lateral spreading must be considered to be a competitive process when studying penetration processes of topically applied substances. It has to be considered during drug treatment of small limited skin areas and for the interpretation of recovery rates obtained in penetration studies.


Subject(s)
Alkanes/pharmacokinetics , Benzoates/pharmacokinetics , Chalcones , Epidermis/metabolism , Skin Absorption , Sunscreening Agents/pharmacokinetics , Administration, Cutaneous , Adolescent , Adult , Alkanes/administration & dosage , Benzoates/administration & dosage , Camphor/administration & dosage , Camphor/analogs & derivatives , Camphor/pharmacokinetics , Chemistry, Pharmaceutical , Emulsions , Humans , Middle Aged , Propiophenones , Sunscreening Agents/administration & dosage , Ultraviolet Rays
14.
Pharmacopsychiatry ; 36(3): 98-104, 2003 May.
Article in English | MEDLINE | ID: mdl-12806567

ABSTRACT

Therapeutic drug monitoring (TDM) of tricyclic antidepressants (TCA) is established in the treatment of depression to optimize outcome and safety. However, there are few reports on TDM under naturalistic clinical conditions. In the present study, we investigated a TDM group (TDM) and a randomly assigned parallel group without TDM (no-TDM) while on TCA treatment. Serum levels were analyzed in both cohorts, but feedback and dose recommendation were only provided for the TDM group. Serum levels of TCA were assessed by high-performance liquid chromatography (HPLC). The outcome was measured weekly using the Hamilton Depression Rating Scale (HAMD), the Clinical Global Impressions Scale (CGI), and the UKU side-effect scale. 84 patients with depressive disorder according to DSM-IV were recruited in three centers (TDM, n = 43; no-TDM, n = 41; mean age 49.9 +/- 13.2 years, 63.1 % female). Patients were treated with either amitriptyline (n = 69) or doxepin (n = 15); the mean dosage at endpoint was 126 +/- 35 mg and 155 +/- 47 mg, respectively. The mean study duration was 21 +/- 8 days. Both groups improved according to HAMD (from 25.2 +/- 8.4 at baseline to 12.0 +/- 7.4 at endpoint) and CGI scores (68 % responders). Moderately severe or severe side effects occurred in 16 % of patients. Adequate dose adjustment was significantly higher in the TDM group (60 % vs. 46 %, p < 0.05); this led to a significantly higher rate of therapeutic serum levels in the TDM group (58 % vs. 44 %, p < 0.05). Direct effects of TDM were not found for effectiveness. Therapeutic TCA serum levels over weeks one to three, however, were associated with significantly better outcome at endpoint (p < 0.05) as measured with changes in the HAMD or CGI response rates from baseline to endpoint. Finally, considerable side effects occurred significantly more often when serum levels were above the therapeutic range (27 % vs. 11 %; p < 0.01). We conclude that treating depression with TCA can be optimized by early TDM, which is superior to clinical judgment on its own. Since the psychiatrists in charge were less than completely "compliant" to the recommendations provided together with serum levels, the effect could be more pronounced than this study shows. The results encourage further studies in order to optimize antidepressant pharmacotherapy when using TDM appropriately.


Subject(s)
Amitriptyline/therapeutic use , Antidepressive Agents, Tricyclic/therapeutic use , Depressive Disorder/drug therapy , Doxepin/therapeutic use , Drug Monitoring/methods , Amitriptyline/adverse effects , Amitriptyline/blood , Antidepressive Agents, Tricyclic/adverse effects , Antidepressive Agents, Tricyclic/blood , Depressive Disorder/blood , Doxepin/adverse effects , Doxepin/blood , Female , Humans , Male , Middle Aged , Psychiatric Status Rating Scales , Treatment Outcome
15.
Skin Pharmacol Appl Skin Physiol ; 16(4): 217-27, 2003.
Article in English | MEDLINE | ID: mdl-12784061

ABSTRACT

The accurate determination of the mass of the horny layer removed by tape stripping is a decisive prerequisite for the application of this technique in penetration studies. A novel method using optical spectroscopy to determine the amount of stratum corneum (SC) is presented. We could show that the absorbance measured in the visible spectral range accurately reflects the mass of the SC fixed on individual tapes. Furthermore, absorbance measurement allows determination of the absolute mass of corneocyte aggregates on the removed tape strips. Topically applied substances do not disturb the spectroscopic measurements in contrast to the conventionally employed weight determination. Identical results were obtained when performing spectroscopic horny layer quantification independently in two separate institutions. Taken together, this new method is rapid, sensitive, reproducible, and accurate. We anticipate a wide application in penetration studies as well as in dermatopharmacokinetics.


Subject(s)
Epidermis/anatomy & histology , Specimen Handling/methods , Spectrophotometry/methods , Adult , Epidermal Cells , Female , Humans , Male , Spectrophotometry, Ultraviolet
16.
Skin Pharmacol Appl Skin Physiol ; 16(4): 228-36, 2003.
Article in English | MEDLINE | ID: mdl-12784062

ABSTRACT

Tape stripping is a well-known method to study the barrier function of the stratum corneum (SC) and penetration processes of topically applied substances into the horny layer. The quantification of the removed corneocytes for each tape strip is the prerequisite for these studies. The pseudo-absorption of the corneocytes was proposed as a measure for the quantification of the removed corneocyte aggregates. In this study, the pseudo-absorption of the corneocytes in the visible range (430 nm) is compared with the protein absorption in the UV range (278 nm) and an absorption at 652 nm obtained after staining of the SC proteins with Trypan blue. Both the protein absorption and the absorption measured after staining correlate well with the pseudo-absorption measured at 430 nm (R(2) = 0.92 +/- 0.04 and R(2) = 0.95 +/- 0.04, respectively).


Subject(s)
Epidermal Cells , Proteins/chemistry , Specimen Handling/methods , Spectrophotometry/methods , Adult , Epidermis/chemistry , Female , Humans , Male , Middle Aged , Spectrophotometry, Ultraviolet , Staining and Labeling , Ultraviolet Rays
18.
J Chromatogr B Biomed Sci Appl ; 759(1): 63-71, 2001 Aug 05.
Article in English | MEDLINE | ID: mdl-11499630

ABSTRACT

An automated method for simultaneous routine quantification of the antipsychotic drugs clozapine, olanzapine and their demethylated metabolites is described. The method included adsorption on a cyanopropyl (CPS) coated clean-up column (10 microm; 10 x 2.0 mm I.D.), washing off interfering serum constituents to waste, and separation on C18 ODS Hypersil reversed phase material (5 microm; 250 x 4.6 mm I.D.) using acetonitrile-water-tetramethylethylenediamine (37:62.6:0.4, v/v/v) adjusted to pH 6.5 with concentrated acetic acid. UV-detection was performed at 254 nm. The limit of quantification was 10-20 ng/ml. Relative day to day standard variations ranged between 4.5 and 13.5%. The method is suitable for routine monitoring of olanzapine and clozapine including their demethylated metabolites.


Subject(s)
Antipsychotic Agents/blood , Chromatography, High Pressure Liquid/methods , Clozapine/blood , Pirenzepine/analogs & derivatives , Pirenzepine/blood , Benzodiazepines , Humans , Olanzapine , Reproducibility of Results , Sensitivity and Specificity , Spectrophotometry, Ultraviolet
19.
Skin Pharmacol Appl Skin Physiol ; 14 Suppl 1: 17-22, 2001.
Article in English | MEDLINE | ID: mdl-11509902

ABSTRACT

The influence of specific follicle properties, sebum production and hair growth on the follicular penetration of topically applied substances was investigated. The behavior of follicles identified in selected skin areas of volunteers was analyzed by various tape stripping and staining methods in combination with laser scanning microscopy. Furthermore hair growth in the selected skin areas was determined. A correlation between sebum production, hair growth activity and follicular penetration was observed.


Subject(s)
Hair Follicle/metabolism , Skin Absorption/physiology , Administration, Topical , Coloring Agents , Cyanoacrylates , Hair/growth & development , Humans , Image Processing, Computer-Assisted , Microscopy, Fluorescence , Osmium Tetroxide , Sebum/metabolism
20.
Skin Pharmacol Appl Skin Physiol ; 14 Suppl 1: 98-102, 2001.
Article in English | MEDLINE | ID: mdl-11509914

ABSTRACT

Tape-stripping and optical spectroscopy are used as a suitable combined method to determine the horny layer profile. Firstly, typical ultraviolet filter substances are used as active substances which are fixed inside the horny layer. Secondly, clobetasol propionate was applied topically in two formulations, Temovate Cream and Temovate and Emollient. The measured changes in the local distribution of the drug inside stratum corneum reflect the observed differences in the biological response visualized as blanching. The concentration of the drug in deeper parts of the horny layer proposes the existence of a small channel available for the percutaneous absorption. The observed low intensity blanching is correlated to the follicle orifices of the skin. After application of Temovate and Emollient, a lateral spreading of the drug must be taken into account.


Subject(s)
Dermatologic Agents/metabolism , Skin/metabolism , Administration, Topical , Biological Availability , Clobetasol/administration & dosage , Clobetasol/analogs & derivatives , Clobetasol/metabolism , Clobetasol/pharmacokinetics , Dermatologic Agents/chemistry , Glucocorticoids/administration & dosage , Glucocorticoids/metabolism , Glucocorticoids/pharmacokinetics , Humans , Skin/chemistry , Sunscreening Agents/metabolism , Sunscreening Agents/pharmacokinetics
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