Question

Which of the following drug molecule does not exhibit fluorescence?

• A. \( \text{Oxytetracycline} \)
• B. \( \text{Paracetamol} \)
• C. \( \text{Quinine} \)
• D. \( \text{Riboflavin} \)

Hint:

Think of quinine in tonic water glowing under UV light – that's fluorescence. Paracetamol doesn't have that property.

Answer 1

The Correct Option is B

Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation of a different wavelength. The ability of a molecule to fluoresce depends on its electronic structure and the presence of rigid planar structures with conjugated \( \pi \)-electron systems. - Oxytetracycline is a tetracycline antibiotic known to exhibit fluorescence, particularly under UV light. - Paracetamol (acetaminophen) generally does not exhibit significant native fluorescence under typical conditions used in pharmaceutical analysis. While some degradation products might fluoresce, the intact molecule has weak fluorescence. - Quinine, an antimalarial drug, is well-known for its strong fluorescence, which is even visible under UV light and is the basis of some analytical methods. - Riboflavin (vitamin B2) is a fluorescent molecule with characteristic excitation and emission spectra. Therefore, paracetamol is the drug molecule among the options that does not typically exhibit significant fluorescence.