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Question

Posted on: March 6 2013

Gelules prescribed as zinc acetate 75 mg. but zinkacetaatanhydrate (M = 183.46) is not available.

Possible approaches:
  • theorem 1: deliver as zinc acetate. dihydrate (M = 219.46) 75 mg. The presence of crystal water is not taken into account. (The zinc content is therefore lower than effectively prescribed) (same reasoning as for morphine delivered as hydrochloride without increasing the quantity)
  • theorem 2: taking into account crystal water, each capsule should contain 90 mg zinc acetate. dihydrate.
A discussion of this trend did not give a conclusive answer. Like your opinion.

Answer

I follow stelling 2. The comparison with morphine does not completely occur there when morphine is prescribed there is thought of the hydrochloride salt; After all morphine base has never been available. In addition, converted to the hydrochloride, the difference will not be as large and this due to the high molecular mass of morphine.