Abstract: Compositions and methods for detecting the presence and/or amount of one or more analytes, including analytes such as drugs of abuse, are provided. The compositions include two or more analytes associated with a solid phase, e.g., a particle or a multiwell plate. The compositions and methods also allow the simultaneous, tandem, or serial determination of the presence and/or amount of two or more analytes of interest in a sample.

Abstract: Methods for assessing the condition of keratinized structures, including hair, in particular methods to determine the condition of keratinized structures in relation to suitability for analysis of analytes of interest in a test sample, are presented. The methods comprise contacting the keratinized structure with a non-proteolytic reducing agent and an optional proteolytic agent. The methods further include inspection of the hair sample, or measurement of free protein eluted from the keratinized structure, after reduction and optional proteolysis to determine condition prior to analyte identification and quantitation by known techniques such as immunoassays.

Abstract: Methods for assessing the condition of keratinized structures, including hair, in particular methods to determine the condition of keratinized structures in relation to suitability for analysis of analytes of interest in a test sample, are presented. The methods comprise contacting the keratinized structure with a non-proteolytic reducing agent and an optional proteolytic agent. The methods further include inspection of the hair sample, or measurement of free protein eluted from the keratinized structure, after reduction and optional proteolysis to determine condition prior to analyte identification and quantitation by known techniques such as immunoassays.

Abstract: Methods that permit the rapid release of one or more analytes from head or body hair or other keratinized structures of an individual (who may previously have ingested one or more of the analytes) are provided. The methods can include contacting the keratinized structure with a reducing agent but not with a proteolytic agent. The methods can further include identification and quantification of the one or more analytes by known analytical techniques such as immunoassays. The described methods do not damage the analyte and do not cause harmful effects on a subsequently-used analyte detection probe (e.g., an antibody).

Abstract: Methods that permit the rapid release of one or more analytes from head or body hair or other keratinized structures of an individual (who may previously have ingested one or more of the analytes) are provided. The methods can include contacting the keratinized structure with a reducing agent but not with a proteolytic agent. The methods can further include identification and quantification of the one or more analytes by known analytical techniques such as immunoassays. The described methods do not damage the analyte and do not cause harmful effects on a subsequently-used analyte detection probe (e.g., an antibody).

Abstract: Methods that permit the rapid release of one or more analytes from head or body hair or other keratinized structures of an individual (who may previously have ingested one or more of the analytes) are provided. The methods can include contacting the keratinized structure with a reducing agent but not with a proteolytic agent. The methods can further include identification and quantification of the one or more analytes by known analytical techniques such as immunoassays. The described methods do not damage the analyte and do not cause harmful effects on a subsequently-used analyte detection probe (e.g., an antibody).

Abstract: Methods that permit the rapid release of one or more analytes from head or body hair or other keratinized structures of an individual (who may previously have ingested one or more of the analytes) are provided. The methods can include contacting the keratinized structure with a reducing agent but not with a proteolytic agent. The methods can further include identification and quantification of the one or more analytes by known analytical techniques such as immunoassays. The described methods do not damage the analyte and do not cause harmful effects on a subsequently-used analyte detection probe (e.g., an antibody).

Abstract: Methods that permit the rapid release of one or more analytes from head or body hair or other keratinized structures of an individual (who may previously have ingested one or more of the analytes) are provided. The methods can include contacting the keratinized structure with a reducing agent but not with a proteolytic agent. The methods can further include identification and quantification of the one or more analytes by known analytical techniques such as immunoassays. The described methods do not damage the analyte and do not cause harmful effects on a subsequently-used analyte detection probe (e.g., an antibody).

Abstract: A method for the direct analysis of analyte in keratinized structures, e.g., hair, fingernails and toenails, which comprises preparing a mixture containing a low redox potential compound such as dithiothreitol or dithioerythritol, an enzyme suitable for the degradation of the keratin structure and a sample of the keratin structure; permitting the enzyme to at least substantially degrade the sample of keratin structure, filtering the digest solution to remove substances which may interfere with ligand based analytical methods and subjecting the filtered digest solution to analysis to determine the identity and amount of analyte in the keratin substance sample. To accelerate the method, cupric sulfate may be added to the mixture after degradation of the keratin sample. The enzyme may be a peptidase, endopeptidase or proteinase, with papain, chymopapain, and proteinase K being preferred for use in the invention.

Abstract: A method for the direct analysis of the presence of an analyte which becomes embedded in keratinized structures, e.g., hair, fingernails and toenails, from the bloodstream of a subject which comprises preparing a mixture containing dithiothreitol or dithioerythritol (“DTT”), an enzyme suitable for the digestion of the keratin structure and a sample of the keratin structure; permitting the enzyme to digest the sample of keratin structure to form a digest solution, followed by the addition of a salt of a metal of copper, zinc, manganese, iron, lead, cadmium, mercury, silver and cobalt to deactivate the DTT; and finally subjecting the digest solution to analysis to determine the presence of the analyte in the keratin structure sample. The protease enzymes papain, chymopapain, and proteinase K are preferred for use in the invention.

Abstract: A method for the direct analysis of the presence of an analyte which becomes embedded in keratinized structures, e.g., hair, fingernails and toenails, from the bloodstream of a subject which comprises preparing a mixture containing dithiothreitol or dithioerythritol ("DTT"), an enzyme suitable for the digestion of the keratin structure and a sample of the keratin structure; permitting the enzyme to digest the sample of keratin structure to form a digest solution, followed by the addition of a salt of a metal of copper, zinc, manganese, iron, lead, cadmium, mercury, silver and cobalt to deactivate the DTT; and finally subjecting the digest solution to analysis to determine the presence of the analyte in the keratin structure sample. The protease enzymes papain, chymopapain, and proteinase K are preferred for use in the invention.

Abstract: A method for the direct analysis of analyte indicative of marijuana exposure found in keratinized structures, e.g., hair, fingernails and toenails, which comprises preparing a mixture containing dithiothreitol or dithioerythritol, a protease suitable for the digestion of the keratin structure and a sample of the keratin structure; permitting the enzyme to at least substantially digest the sample of keratin structure to form a digest solution, followed by mixing the digest solution with a suspension of an ion exchange resin to remove an interfering, cross reacting substance naturally found in hair and finally subjecting the digest solution to analysis to determine the identity and amount of marijuana analyte in the keratin structure sample. To accelerate the method, cupric sulfate may be added to the mixture after degradation of the keratin sample in order to deactivate the activator. The enzyme may be a protease with papain, chymopapain, and proteinase K being preferred for use in the invention.

Abstract: A method for the direct analysis of analyte in keratinized structures, e.g., hair, fingernails and toenails, which comprises preparing a mixture containing a low redox potential compound such as dithiothreitol or dithioerythritol, an enzyme suitable for the degradation of the keratin structure and a sample of the keratin structure; permitting the enzyme to at least substantially degrade the sample of keratin structure, and subjecting the mixture to analysis to determine the identity and amount of analyte in the keratin substance sample. To accelerate the method, cupric sulfate or sodium arsenite may be added to the mixture after degradation of the keratin sample. The enzyme may be a peptidase, endopeptidase or proteinase, with papain, chymopapain, and proteinase K being preferred for use in the invention.