Question
Posted on: March 6 2013An unstable suspension with benzoyl peroxide and erythromycin benzoyl peroxide BZPO 5% erythromycin 3% Idroramnosan 3% Ethanol 94 ° 10.70% Propylene glycol 5.90% Aqua
Dist AD 30g < br/> After very long stirring we obtain a white suspension that does not seem stable to me.
Answer
The reason of the instabilitite lies in the incompatibility of Idroramnosan (Hydroxyethylcellulose or HEC) with a higher concentration of ethanol. I would replace HEC with HPC (Hydroxyprpylcellulose or Klucel).
Tarreer A small light mortar with pestle. Note tare weight (T). Bring BZPO into the mortar and add 5 ml of chloroform. Rub until dry. Ensure that all chloroform evaporates by leaving a time. Mix with the BZPO erythromycin + hydroxypropyl celluosis. Weigh in the mortar propylene glycol and rub the powder mixture into a homogeneous paste. Add alcohol and mix. Bring on weight (T + 30) with freshly boiled and cooled water.
Tarreer A small light mortar with pestle. Note tare weight (T). Bring BZPO into the mortar and add 5 ml of chloroform. Rub until dry. Ensure that all chloroform evaporates by leaving a time. Mix with the BZPO erythromycin + hydroxypropyl celluosis. Weigh in the mortar propylene glycol and rub the powder mixture into a homogeneous paste. Add alcohol and mix. Bring on weight (T + 30) with freshly boiled and cooled water.