The Experts below are selected from a list of 27 Experts worldwide ranked by ideXlab platform

Ulla Hoeck - One of the best experts on this subject based on the ideXlab platform.

  • FS05.3 New characterization and chemistry of Germall 115 and Germall II
    Contact Dermatitis, 2008
    Co-Authors: Søren Vig Lehmann, Ulla Hoeck, Jens Breinholdt, Carl Erik Olsen
    Abstract:

    Germall 115 and Germall II are well known cosmetic preservatives, widely used as such since the early 1970’s and 1980’s, respectively. This investigation reveals that they have mistakenly been regarded as pure chemical entities with specific structures by the majority of the chemical society. In fact Germall 115 and Germall II both consist of complex mixtures of numerous and fast degradable allantoin-formaldehyde condensation products and may not even contain the conventionally assigned chemical structures of imidazolidinyl urea (Germall 115) and diazolidinyl urea (Germall II). Equilibrium between different structures may be formed in different cosmetic formulations/test materials. This may have led to the discrepancies in the literature: Are the Germalls themselves sensitizers or are the allergic reactions caused by formaldehyde release? The identification and structure assignment of (4-hydroxymethyl-2,5-dioxo-imidazolidin-4-yl)-urea (HU) will be presented, as it is the major and chemically stable degradation product of both Diazolidinyl urea and Imidazolidinyl urea. A guinea pig maximization test has been performed to determine the potential of HU to induce delayed contact hypersensibility in guinea pigs. Separate chemically stable TRUE Test patches containing the mixtures have shown clinical efficacy.

  • FS05.6 New standardized allergens: the experimental TRUE Test® Panel
    Contact Dermatitis, 2008
    Co-Authors: Ulla Hoeck, Søren Vig Lehmann, H Bjarnoe, J Meldgaard, L Holm Laugesen
    Abstract:

    TRUE Test® is the only standardized patch test system for the diagnosis of allergic contact dermatitis based on 24 fully stable and reproducible formulations. New standardized patches are in process of development for TRUE Test® Panel 3. The allergens chosen are well-known sensitizers and include preservatives, steroids, metals and others. 14 new patches are included in an Experimental panel which is tested in several European clinics. 11 of the patches contain new allergens while 3 patches consist of improved TRUE Test® formulations with Neomycine sulphate, Fragrance mix and Potassium dichromate. A number of the patches from the Experimental panel will be selected for TRUE Test® Panel 3. The overall purpose with pharmaceutical development of patch test materials for TRUE Test® is to obtain a precise dose, bioavailability and stability in every single patch. The patches have to be chemically stable for at least 2 years at refrigerated temperature. The selected preservatives on the Experimental panel are Methyldibromoglutaronitrile, Germall 115, Germall II and Bronopol. All 4 patches have proven to be difficult to stabilize because of the natural reactivity of the allergenic substances. The steroids chosen are Budesonide, Tixocortol-21-pivalate and Hydrocortisone-17-butyrate. All 3 steroids are stable in TRUE Test® formulations. Other allergens on the Experimental panel are Ammoniated Mercury, Goldsodiumthiosulphate, Parthenolide and Disperse blue 106, where the latter consists of a complex mixture. Chemical stabilization of the patches as well as clinical studies will be presented.

  • Characterization and chemistry of imidazolidinyl urea and diazolidinyl urea.
    Contact dermatitis, 2006
    Co-Authors: Søren Vig Lehmann, Ulla Hoeck, Jens Breinholdt, Carl Erik Olsen, Bo Kreilgaard
    Abstract:

    For several decades, the cosmetic preservatives imidazolidinyl urea (IU) and diazolidinyl urea (DU) have not only been poorly characterized but have also had misleading chemical structures assigned to them. The most common trade names of IU and DU are Germall 115 and Germall II, respectively. This publication gives an insight into what these 2 well-known contact allergens consist of and their degradation patterns. Approximately, 30-40% of both products can be characterized by mixtures of allantoin (synthetic starting material), (4-hydroxymethyl-2,5-dioxo-imidazolidin-4-yl)-urea (compound HU) and presumably 1-(3,4-bis-hydroxymethyl-2,5-dioxo-imidazolidin-4-yl)-1,3-bis-hydroxymethyl-urea (compound BHU). A full chemical characterization of compound HU is shown. The remaining part of both IU and DU are believed to be polymers of allantoin-formaldehyde condensation products. The analytical methods used to characterize IU and DU are capillary electrophoresis and nuclear magnetic resonance and mass spectroscopy studies.

  • Standardization of the TRUE Test imidazolidinyl urea and diazolidinyl urea patches
    Contact dermatitis, 2001
    Co-Authors: Tove Agner, Klaus Ejner Andersen, Torkil Menné, Ulla Hoeck, Bo Kreilgaard, Bert Björkner, Magnus Bruze, P. J. Frosch, B Gruvberger, J Sommer
    Abstract:

    The preservatives imidazolidinyl urea (IMID, Germall 115) and diazolidinyl urea (DU, Germall II) are commonly used in cosmetic products and are well-known sensitizers. The aim of the present study was to establish the optimal patch test concentration in hydrophilic dried-in vehicle (TRUE Test) for IMID and DU. 181 patients were included in the study. Of these, 150 were patients referred for patch testing, 12 were patients with known allergy to IMID and 19 were patients with known allergy to DU. 76 consecutive patients and the 12 IMID-allergic patients were patch tested with a dilution series IMID (0 to 600 microg/cm(2)), formaldehyde (180 microg/cm(2)) and DU (200 microg/cm(2)). 74 consecutive patients and the 19 DU-allergic patients were patch tested with a dilution series of DU (0 to 600 microg/cm(2)), formaldehyde (180 microg/cm) and IMID (200 microg/cm(2)). A positive dose-response relationship was found. The number of doubtful reactions decreased with increasing test concentrations. No late reactions were observed. A patch test concentration in hydrophilic dried-in vehicle (TRUE Test) of 600 microg/cm(2) was found to be adequate and safe for both IMID and DU.

Søren Vig Lehmann - One of the best experts on this subject based on the ideXlab platform.

  • FS05.6 New standardized allergens: the experimental TRUE Test® Panel
    Contact Dermatitis, 2008
    Co-Authors: Ulla Hoeck, Søren Vig Lehmann, H Bjarnoe, J Meldgaard, L Holm Laugesen
    Abstract:

    TRUE Test® is the only standardized patch test system for the diagnosis of allergic contact dermatitis based on 24 fully stable and reproducible formulations. New standardized patches are in process of development for TRUE Test® Panel 3. The allergens chosen are well-known sensitizers and include preservatives, steroids, metals and others. 14 new patches are included in an Experimental panel which is tested in several European clinics. 11 of the patches contain new allergens while 3 patches consist of improved TRUE Test® formulations with Neomycine sulphate, Fragrance mix and Potassium dichromate. A number of the patches from the Experimental panel will be selected for TRUE Test® Panel 3. The overall purpose with pharmaceutical development of patch test materials for TRUE Test® is to obtain a precise dose, bioavailability and stability in every single patch. The patches have to be chemically stable for at least 2 years at refrigerated temperature. The selected preservatives on the Experimental panel are Methyldibromoglutaronitrile, Germall 115, Germall II and Bronopol. All 4 patches have proven to be difficult to stabilize because of the natural reactivity of the allergenic substances. The steroids chosen are Budesonide, Tixocortol-21-pivalate and Hydrocortisone-17-butyrate. All 3 steroids are stable in TRUE Test® formulations. Other allergens on the Experimental panel are Ammoniated Mercury, Goldsodiumthiosulphate, Parthenolide and Disperse blue 106, where the latter consists of a complex mixture. Chemical stabilization of the patches as well as clinical studies will be presented.

  • FS05.3 New characterization and chemistry of Germall 115 and Germall II
    Contact Dermatitis, 2008
    Co-Authors: Søren Vig Lehmann, Ulla Hoeck, Jens Breinholdt, Carl Erik Olsen
    Abstract:

    Germall 115 and Germall II are well known cosmetic preservatives, widely used as such since the early 1970’s and 1980’s, respectively. This investigation reveals that they have mistakenly been regarded as pure chemical entities with specific structures by the majority of the chemical society. In fact Germall 115 and Germall II both consist of complex mixtures of numerous and fast degradable allantoin-formaldehyde condensation products and may not even contain the conventionally assigned chemical structures of imidazolidinyl urea (Germall 115) and diazolidinyl urea (Germall II). Equilibrium between different structures may be formed in different cosmetic formulations/test materials. This may have led to the discrepancies in the literature: Are the Germalls themselves sensitizers or are the allergic reactions caused by formaldehyde release? The identification and structure assignment of (4-hydroxymethyl-2,5-dioxo-imidazolidin-4-yl)-urea (HU) will be presented, as it is the major and chemically stable degradation product of both Diazolidinyl urea and Imidazolidinyl urea. A guinea pig maximization test has been performed to determine the potential of HU to induce delayed contact hypersensibility in guinea pigs. Separate chemically stable TRUE Test patches containing the mixtures have shown clinical efficacy.

  • Characterization and chemistry of imidazolidinyl urea and diazolidinyl urea.
    Contact dermatitis, 2006
    Co-Authors: Søren Vig Lehmann, Ulla Hoeck, Jens Breinholdt, Carl Erik Olsen, Bo Kreilgaard
    Abstract:

    For several decades, the cosmetic preservatives imidazolidinyl urea (IU) and diazolidinyl urea (DU) have not only been poorly characterized but have also had misleading chemical structures assigned to them. The most common trade names of IU and DU are Germall 115 and Germall II, respectively. This publication gives an insight into what these 2 well-known contact allergens consist of and their degradation patterns. Approximately, 30-40% of both products can be characterized by mixtures of allantoin (synthetic starting material), (4-hydroxymethyl-2,5-dioxo-imidazolidin-4-yl)-urea (compound HU) and presumably 1-(3,4-bis-hydroxymethyl-2,5-dioxo-imidazolidin-4-yl)-1,3-bis-hydroxymethyl-urea (compound BHU). A full chemical characterization of compound HU is shown. The remaining part of both IU and DU are believed to be polymers of allantoin-formaldehyde condensation products. The analytical methods used to characterize IU and DU are capillary electrophoresis and nuclear magnetic resonance and mass spectroscopy studies.

Carl Erik Olsen - One of the best experts on this subject based on the ideXlab platform.

  • FS05.3 New characterization and chemistry of Germall 115 and Germall II
    Contact Dermatitis, 2008
    Co-Authors: Søren Vig Lehmann, Ulla Hoeck, Jens Breinholdt, Carl Erik Olsen
    Abstract:

    Germall 115 and Germall II are well known cosmetic preservatives, widely used as such since the early 1970’s and 1980’s, respectively. This investigation reveals that they have mistakenly been regarded as pure chemical entities with specific structures by the majority of the chemical society. In fact Germall 115 and Germall II both consist of complex mixtures of numerous and fast degradable allantoin-formaldehyde condensation products and may not even contain the conventionally assigned chemical structures of imidazolidinyl urea (Germall 115) and diazolidinyl urea (Germall II). Equilibrium between different structures may be formed in different cosmetic formulations/test materials. This may have led to the discrepancies in the literature: Are the Germalls themselves sensitizers or are the allergic reactions caused by formaldehyde release? The identification and structure assignment of (4-hydroxymethyl-2,5-dioxo-imidazolidin-4-yl)-urea (HU) will be presented, as it is the major and chemically stable degradation product of both Diazolidinyl urea and Imidazolidinyl urea. A guinea pig maximization test has been performed to determine the potential of HU to induce delayed contact hypersensibility in guinea pigs. Separate chemically stable TRUE Test patches containing the mixtures have shown clinical efficacy.

  • Characterization and chemistry of imidazolidinyl urea and diazolidinyl urea.
    Contact dermatitis, 2006
    Co-Authors: Søren Vig Lehmann, Ulla Hoeck, Jens Breinholdt, Carl Erik Olsen, Bo Kreilgaard
    Abstract:

    For several decades, the cosmetic preservatives imidazolidinyl urea (IU) and diazolidinyl urea (DU) have not only been poorly characterized but have also had misleading chemical structures assigned to them. The most common trade names of IU and DU are Germall 115 and Germall II, respectively. This publication gives an insight into what these 2 well-known contact allergens consist of and their degradation patterns. Approximately, 30-40% of both products can be characterized by mixtures of allantoin (synthetic starting material), (4-hydroxymethyl-2,5-dioxo-imidazolidin-4-yl)-urea (compound HU) and presumably 1-(3,4-bis-hydroxymethyl-2,5-dioxo-imidazolidin-4-yl)-1,3-bis-hydroxymethyl-urea (compound BHU). A full chemical characterization of compound HU is shown. The remaining part of both IU and DU are believed to be polymers of allantoin-formaldehyde condensation products. The analytical methods used to characterize IU and DU are capillary electrophoresis and nuclear magnetic resonance and mass spectroscopy studies.

Jens Breinholdt - One of the best experts on this subject based on the ideXlab platform.

  • FS05.3 New characterization and chemistry of Germall 115 and Germall II
    Contact Dermatitis, 2008
    Co-Authors: Søren Vig Lehmann, Ulla Hoeck, Jens Breinholdt, Carl Erik Olsen
    Abstract:

    Germall 115 and Germall II are well known cosmetic preservatives, widely used as such since the early 1970’s and 1980’s, respectively. This investigation reveals that they have mistakenly been regarded as pure chemical entities with specific structures by the majority of the chemical society. In fact Germall 115 and Germall II both consist of complex mixtures of numerous and fast degradable allantoin-formaldehyde condensation products and may not even contain the conventionally assigned chemical structures of imidazolidinyl urea (Germall 115) and diazolidinyl urea (Germall II). Equilibrium between different structures may be formed in different cosmetic formulations/test materials. This may have led to the discrepancies in the literature: Are the Germalls themselves sensitizers or are the allergic reactions caused by formaldehyde release? The identification and structure assignment of (4-hydroxymethyl-2,5-dioxo-imidazolidin-4-yl)-urea (HU) will be presented, as it is the major and chemically stable degradation product of both Diazolidinyl urea and Imidazolidinyl urea. A guinea pig maximization test has been performed to determine the potential of HU to induce delayed contact hypersensibility in guinea pigs. Separate chemically stable TRUE Test patches containing the mixtures have shown clinical efficacy.

  • Characterization and chemistry of imidazolidinyl urea and diazolidinyl urea.
    Contact dermatitis, 2006
    Co-Authors: Søren Vig Lehmann, Ulla Hoeck, Jens Breinholdt, Carl Erik Olsen, Bo Kreilgaard
    Abstract:

    For several decades, the cosmetic preservatives imidazolidinyl urea (IU) and diazolidinyl urea (DU) have not only been poorly characterized but have also had misleading chemical structures assigned to them. The most common trade names of IU and DU are Germall 115 and Germall II, respectively. This publication gives an insight into what these 2 well-known contact allergens consist of and their degradation patterns. Approximately, 30-40% of both products can be characterized by mixtures of allantoin (synthetic starting material), (4-hydroxymethyl-2,5-dioxo-imidazolidin-4-yl)-urea (compound HU) and presumably 1-(3,4-bis-hydroxymethyl-2,5-dioxo-imidazolidin-4-yl)-1,3-bis-hydroxymethyl-urea (compound BHU). A full chemical characterization of compound HU is shown. The remaining part of both IU and DU are believed to be polymers of allantoin-formaldehyde condensation products. The analytical methods used to characterize IU and DU are capillary electrophoresis and nuclear magnetic resonance and mass spectroscopy studies.

Bo Kreilgaard - One of the best experts on this subject based on the ideXlab platform.

  • Characterization and chemistry of imidazolidinyl urea and diazolidinyl urea.
    Contact dermatitis, 2006
    Co-Authors: Søren Vig Lehmann, Ulla Hoeck, Jens Breinholdt, Carl Erik Olsen, Bo Kreilgaard
    Abstract:

    For several decades, the cosmetic preservatives imidazolidinyl urea (IU) and diazolidinyl urea (DU) have not only been poorly characterized but have also had misleading chemical structures assigned to them. The most common trade names of IU and DU are Germall 115 and Germall II, respectively. This publication gives an insight into what these 2 well-known contact allergens consist of and their degradation patterns. Approximately, 30-40% of both products can be characterized by mixtures of allantoin (synthetic starting material), (4-hydroxymethyl-2,5-dioxo-imidazolidin-4-yl)-urea (compound HU) and presumably 1-(3,4-bis-hydroxymethyl-2,5-dioxo-imidazolidin-4-yl)-1,3-bis-hydroxymethyl-urea (compound BHU). A full chemical characterization of compound HU is shown. The remaining part of both IU and DU are believed to be polymers of allantoin-formaldehyde condensation products. The analytical methods used to characterize IU and DU are capillary electrophoresis and nuclear magnetic resonance and mass spectroscopy studies.

  • Standardization of the TRUE Test imidazolidinyl urea and diazolidinyl urea patches
    Contact dermatitis, 2001
    Co-Authors: Tove Agner, Klaus Ejner Andersen, Torkil Menné, Ulla Hoeck, Bo Kreilgaard, Bert Björkner, Magnus Bruze, P. J. Frosch, B Gruvberger, J Sommer
    Abstract:

    The preservatives imidazolidinyl urea (IMID, Germall 115) and diazolidinyl urea (DU, Germall II) are commonly used in cosmetic products and are well-known sensitizers. The aim of the present study was to establish the optimal patch test concentration in hydrophilic dried-in vehicle (TRUE Test) for IMID and DU. 181 patients were included in the study. Of these, 150 were patients referred for patch testing, 12 were patients with known allergy to IMID and 19 were patients with known allergy to DU. 76 consecutive patients and the 12 IMID-allergic patients were patch tested with a dilution series IMID (0 to 600 microg/cm(2)), formaldehyde (180 microg/cm(2)) and DU (200 microg/cm(2)). 74 consecutive patients and the 19 DU-allergic patients were patch tested with a dilution series of DU (0 to 600 microg/cm(2)), formaldehyde (180 microg/cm) and IMID (200 microg/cm(2)). A positive dose-response relationship was found. The number of doubtful reactions decreased with increasing test concentrations. No late reactions were observed. A patch test concentration in hydrophilic dried-in vehicle (TRUE Test) of 600 microg/cm(2) was found to be adequate and safe for both IMID and DU.