Method of detecting drug taggants in biological samples to assess drug decay

A method of detecting drug taggants in biological sample to assess decay of a drug in a drug composition comprising the steps of:

• a) detecting a signal produced by a first and a second drug taggant in the biological sample which was collected from a user who has consumed at least one drug composition,
• i. wherein each of the at least one drug composition comprises the following, each in a known quantity and in a first ratio, at the time of manufacture of the drug composition:
• at least one drug or placebo, and the first and the second drug taggants,
• ii. wherein the first drug taggant comprises a first decay characteristic and the second drug taggant comprises a second decay characteristic,
• iii. wherein the first decay characteristic is detectably different from the second decay characteristic, and
• iv. wherein the at least one drug or placebo comprises the first and the second decay characteristics;
• v. wherein the first decay characteristic and the second decay characteristic are independently selected from the following:
• decay due to light sensitivity, decay due to temperature sensitivity, and decay due to moisture;
• vi. wherein the first decay characteristic is a qualitatively different characteristic than the second decay characteristic;
• and
• vii. wherein the first decay characteristic is qualitatively the same as a decay characteristic possessed by the drug, and wherein the first decay characteristic is kinetically approximately the same as the decay characteristic possessed by the drug;
• and
• viii. wherein the first drug taggant and the second drug taggant are independently selected from the following:
• polyethylene glycol, copovidone, povidone, propyl paraben, methyl paraben, acesulfame potassium, mannitol, sorbitol, xylitol, steviol glucuronide, sucralose, oleic acid, trans-anethole, 1,8-eucalyptol, limonene-2D, riboflavin, tartaric acid, salts of tartaric acid, linalool, and citronellol;
• and
• b) calculating a second ratio of the first and the second drug taggants present in the biological sample;
• c) identifying one or more decay characteristics which caused the decay of the drug;
• and
• d) extrapolating a difference between the first ratio and the second ratio to determine a fraction of decayed drug.