25% sodium thiosulphate in the topical treatment of calciphylaxis
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European Statement
Production and Compounding
Author(s)
VIRGINIA PUEBLA GARCIA, MARIA MOLINERO MUÑOZ, ANA ANDREA GARCIA SACRISTAN, JAVIER CORAZON VILLANUEVA, LIDIA YBAÑEZ GARCIA, NATALIA SANCHEZ-OCAÑA MARTIN, PALOMA PASTOR VARA, MARIA FERNANDEZ-VAZQUEZ CRESPO, JOSE MANUEL MARTINEZ SESMERO
Why was it done?
Calciphylaxis is a vascular disorder characterised by the accumulation of calcium in the small blood vessels of the skin and adipose tissue. There is an imbalance in calcium metabolism which causes calcium to be deposited in the arterioles favouring thrombosis in the residual lumen of these vessels. It presents with severe painful skin lesions which progress to ulcers. It mostly affects patients on renal replacement therapy.
What was done?
To describe the making process of a 25% sodium thiosulphate ointment (ST25%) requested by the Nephrology Department as an off-label use for the topical treatment of calciphylaxis in a patient who was unable to use intravenous sodium thiosulphate (ST) due to haemodynamic instability.
How was it done?
We initially performed an online literature search of databases related to raw materials and excipients, experience of use with formulas prepared by other hospitals as well as articles related to calciphylaxis.
For the production and quality control, the Standard Operating Procedure (SOP) for ointments described in the National Formulary was followed. To establish the risk level of the preparation and the expiry date, a risk matrix was used according to the Guide to Good Pharmacy Preparation Practice (GBPP).
What has been achieved?
It was decided to make a ST25% ointment. Composition for 100 g: ST 25 g (active ingredient), glycerine 10 g (humectant, cosolvent), pure lanolin 32.5 g and white filmy petrolatum 32.5 g (vehicles).
Production: the ST crystals were pulverised in a mortar. Glycerine was gradually added on top of the ST until a uniform whitish paste free of crystals was formed. At the same time, lanolin and filmy petrolatum was mixed in the final container with the help of an emulsifier. Finally, the paste formed with ST and glycerine was added to the lanolin-Vaseline mixture and stirred in the emulsifier until a homogeneous ointment was obtained.
A yellowish ointment with a homogeneous appearance, oily texture and no crystals was obtained.
Expiry date: 30 days after opening. Low-risk preparation.
What next?
Calciphylaxis could be treated after intolerance to intravenous sodium thiosulphate by developing an ointment. The pharmacist through magistral formulation can provide pharmaceutical alternatives in situations where the use of commercially available medicines is not possible.