I am working on degradation of antibiotics at different pH conditions. I found that degradation rate is maximum at pH 3 and 6 for tetracycline and oxy-tetracycline respectively. At pH 3, both the catalyst and tetracycline are positively charged as PZC of the catalyst is measured to be 6.3-6.6. hence, there must be repulsion between them. So, my question is what is the interaction exist between these two so that degradation rate is high at this pH. Does anyone know about this, kindly help.
Thanks in advance.
pH for tetracycline is differ from Oxytetracycline , may be due to (OH) hydroxy group in position 4 in Oxytetracycline leads to this change.
Tetracycline has 3 pKas ( acidic, neutral and basic) due to the functional groups in the structure. Any weak drug will need a suitable buffer or substance for pH profile.
yes, Dr. Faris Abachi Sir, tetracycline has 3 pKa values: 3.3, 7.7 and 9.7. hence at pH 3 it is present in cationic form and the concerned catalyst is also exist in cationic form. so there must be repulsion between them. But surprisingly at this pH, degradation rate is found to be maximum, So my question is what type of inetraction takes place between these two at this pH condition so that the degrdation rate is high?
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