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Posted on: October 29 2015

How to prepare a cream with N-acetylcysteine for the treatment of ichtyosises

We have a patient here with ichthyosis. The treating dermatologist asked us to try out 2 magistal preparations. The formula was taken from Pediatric Dermatology 2014, 31, 395 INGREDIENTS *: Active ingredients and Fonterra excipients for 100 g or final product • N-acetylcysteine 10 g; Urea. 5 g; Sodium hydroxide. 2.5 g; Neo-PCL Base (O/W non-ionic emulsion cream 25 g; Glycerin 5 G; Rosemary oil 1.5 ml; Sterile Water AD 100 ml Method of Preparation: Do not use metallic material during preparation. 1. Measure 55 mL of sterile water with a test tube and place in a beaker. Heat the water in the thermostatic bath up to 50oC to 60oC. 2. Weigh the N-acetylcysteine and the urea and dissolve them slowly with the magnetic stirrer. 3. Incorporate the glycerin and add the sodium hydroxide slowly. Dissolve them using the magnetic stirrer. 4. Measure the pH; Must be between 4.5 and 5.0. 5. Weigh the Neo-PCL and melt it in the thermostatic bath up to 50oC to 60oC. Add the rosemary oil. 6. Remove the Neo-PCL from the bath. Incorporate the water phase into the oil While shaking with the glass stick until it cools down. 7. Finally, reduce the particles and homogenize the mixture with the help of a mixer until it gets an ambient temperature. Quality Control Procedures: • Weight of final product • Visual observation of ointment spread: white, slightly stiff ointment with no visible particles • pH 4.5 to5 Packaging Package in tight, light-resistant containers. Beyond-Use Date Assignment: • The Beyond-use date is 30 days † Use On right leg the treating cream with N-acetylcystëine. On the left leg, the doctor asked us to use the same cream but without acetylcysteine. Our questions are: -Metal spatulas should not be worked on. Is this preparation prone to oxidation, because it does not appear from the structure of acetylcysteine... (Would even be an anti-oxidance itself?) -Cream without acetylcysteine: pH is way too high! We Suppose that NaOH should be omitted from this? As well as the Rosema Rhine oil, which only serves to mask the odor of the acetylcysteine? -What about the preservation of this cream? Are metal tubes suitable? Pot made of plastic not ideal for storage???

Answer

The cream used in the published formula is not available to us and therefore we opt for Cremor Cetomacrogolis FN 6   with parabens   as a preservative, unless there are indications for parabens. But the final   pH of the cream is unfavorable to sorbic acid.  

In This cream occurs approximately 65   g of water per 100 g.   half   of the water is used for the preparation of the cream; the other half for solving of Acetylcysteine. We replaced 5 g Vaseline by 5 G glycerin!

1. Tarreer a beaker of 150 to 200 ml together with a plastic spatula (mass = T)  

2. Boil 75 ml of water and allow to cool to 70 °C  

2. Melt the fat phase of the cream on a hot water bath in the tarred Beaker   and add 35 ml of water (70 °C) and prepare the cream  

3.. To dissolve 10 g of acetylcysteine We put in a beaker 30 g of water (35 °C)     5 g NaHCO3, 100 mg EDTA   and 100 mg nametabisulfite; After solving these constituents, we add the acetylcysteine and place the whole on a magnetic stirrer; Possibly with light (35 ° C)   warming  

4. Once dissolved, we mix the solution with the cream and homogenize

5. We place beaker with cream and spatula on the balance and compensate for the evaporate water. Total weight T + 100