Predict which of the vitamins shown at right would be retained longer in the blo
ID: 66650 • Letter: P
Question
Predict which of the vitamins shown at right would be retained longer in the bloodstream. Explain. Amoxicillin and azithromicin are common antibiotics. Amoxicillin usually is taken every 6 hours for 10 days, while azithromicin is taken once a day for 5 days. Based on these regimens, what can you predict about their half-lives and molecular structures? Explain your predictions. Look up the structures of these antibiotics and half-lives in the body to validate your predictions. Account for any differences.Explanation / Answer
1- Vitamin B3 or niacin is a water-soluble vitamin & the body can absorb it easily. When one takes in excess water-soluble vitamins like B3, the kidneys remove the excess through urine.
On the other hand, vitamin D3 is fat-soluble. The body eliminates D3 more slowly than water-soluble nutrients. Fat-soluble nutrients consumed in excess pose a greater danger of toxicity because these substances can accumulate in the body over time.
So, vitamin D3 will be retained longer in the bloodstream although B3 will be easily circulated along the bloodstream as it is water soluble.
2- Amoxicillin is water-soluble and has a polar structure with a shorter half-life; while Azithromycin is fat-soluble with a complex non-polar structure and has a longer half-life.
Amoxicillin being water-soluble can easily be excreted out through renal pathway (kidneys via urine), so the excess is being excreted out and it is needed to be taken at a shorter interval. Azithromycin is being excreted mainly via bile after it is metabolised in the hepatic tissue, so longer time needed for its excretion.