Question
Posted on: March 6 2013Discoloration of the following solution: Chlorphenaminemaleate 200 mg phenylephrine. HCL 400 mg Naphazoline HCl 30 mg Dina phosphate 120 mg monona phosphate 100 mg NaCl 610 mg
Benzalk. CHL and EDTA QS
Aqua AD 100 ml < BR/> After a few weeks a brown discoloration occurs. Is this due to oxidation of chlorphenamine and if so, what is the most appropriate antioxydance? The pH of the solution is approximately 6.8. Can the phosphate concentration be too low?
Aqua AD 100 ml < BR/> After a few weeks a brown discoloration occurs. Is this due to oxidation of chlorphenamine and if so, what is the most appropriate antioxydance? The pH of the solution is approximately 6.8. Can the phosphate concentration be too low?
Answer
Chloropheniraminemaleate seems to me to be a rather resistant molecule. I would rather expect problems of phenylephrine (similar to adrenaline), which is also oxidation sensitive.
for both products, the optimal pH area appears to be between 4.6 and 5.2. I would therefore use another phosphate buffer. For 100 ml buffer PH 5.2 (80% isotonic) use: 2.0 g NaH2PO4 2 aq and 0.09 G Na2HPO4 2 aq.
If this change is insufficient, your composition can also be added to an antioxidant e.g. Nametabisulfiet 1 pro thousand. Storage should be done outside light influence in well closed bottles. A classic dropper bottle with stand-up droplet may not be ideal because the rubber part is permeable. Maybe better a nasal spray?
I suspect we have to do with nasal drops here. In terms of composition, it may also be a matter of the fact that Naphazoline is an unsurpassed vasoconstrictor and it is better to use Xylometazoline.
for both products, the optimal pH area appears to be between 4.6 and 5.2. I would therefore use another phosphate buffer. For 100 ml buffer PH 5.2 (80% isotonic) use: 2.0 g NaH2PO4 2 aq and 0.09 G Na2HPO4 2 aq.
If this change is insufficient, your composition can also be added to an antioxidant e.g. Nametabisulfiet 1 pro thousand. Storage should be done outside light influence in well closed bottles. A classic dropper bottle with stand-up droplet may not be ideal because the rubber part is permeable. Maybe better a nasal spray?
I suspect we have to do with nasal drops here. In terms of composition, it may also be a matter of the fact that Naphazoline is an unsurpassed vasoconstrictor and it is better to use Xylometazoline.