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Question

Posted on: March 19 2015

Would a "numbe" incompatibility between chlorhexidinedigluconate and Primojel be possible?

We received a request for the preparation of a "loco" preparation for Decusorb according to the following composition: R/Aqua Reversed osmosis 57.69 G, Macrogol 400 5.31 G, solutio Chlorhexidini digluconatis 20% 1.48 g, Carboxymethylamylum Natrijizz A (Primojel) 10.77 g The method of preparation is as follows 1. Dissolve the chlorhexidine and the PEG in water 2. Sprinkle the Primojel on this mixture; 3. Mix immediately in the Stephan mixer with low speed; 4. Speed up after swelling When looking up the incompatibilities, I bumped into a possible interaction between chlorhexidine (+) and Carboxymethylamylum (-). APB advised me to use another gelvormer; e.g. methyl cellulose. The hospital pharmacy, which often prepares this preparation, informs me that this preparation is stable. According to them, Chlorhexidine is added as a preservative

Answer

Indeed the interaction is most likely.   A confirmation is given by a microbiological examination (annex I) conducted by the Laboratory of Pharmaceutical Microbiology UGent  .   Chlorheixidine is in these tests Still for 10% active. This   explains why no contamination was found in previously prepared pastes.  

The suggestion of APB to use a   non-ionogen polymer cannot be followed. After all, Primojel is known for its enormous water absorption capacity, which even exceeds this of starch.

The assertion that chlorhexidine is found in this compound as a preservative (annex II) is incorrect since the prescribed concentration (0.4%) The preservation concentration exceeds.   On the skin a concentration of +/-0.5% is used, while in the oral cavity it is between 0.12 à 0.2%

The solution could be found by the choice of an antispeticum, carrier of a negative charge. But to my knowledge there is not. We can look forward to a non-iongenic substance with bactericidal effect. Personally, I would go for hypochlorite, which is added in the form of Carrel-Dakin solution to pastes and creams, which are used in very necrotic, infected or badly smelling   wounds.  . Chloramine has a strong debriding effect but there is a disadvantage, and this is the cytotoxicity of   hypochlorite. Occurs stagnation of wound healing on   then can be switched to another   product   (enzyme-Alginogel) to stimulate granulation and healing  

The literature also mentions a certain cytoxicity to chlorhexidine.  

Decision: Replace the osmosis water with a solution of chloramine at a concentration of 0.5 g per 100 ml  

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