Qualification of a mixer: how to obtain the homogeneity of semi-solid preparations for skin application (SSPSA)
Hôpital Clocheville, CHRU Tours, France
The non-sterile pharmacy preparatory has been equipped with a mixer in order to limit the musculoskeletal disorders that the pharmaceutical assistants (PA) in hospital develop. At the same time with a study on the mixing of powders, an interest was focused on the use of the new tool for the mixing of SSPSA. The objective of the study is the qualification of the mixer in order to obtain homogeneous mixtures.
The mixing times and speed for each of the preparations were established after discussion with a pharmacy using this mixer, and based on some data from the literature. We have studied and realized several tests on the most commonly produced SSPSAs in our healthcare facility (HF): urea ointment, starch glycerol cold cream, salicylated petroleum jelly (SPJ), Questran® ointment. Blinding tests within the pharmacy team made it possible to evaluate the homogeneity of the mixtures: the subjective appreciation of the texture, the ease of application and the visual homogeneity thanks to the carmine red used as a colored indicator were required. Compliance with the 50% SPJ content has been objectified by setting up the dosage of the content recommended in the national form of the French Pharmacopoeia 11th edition.
SSPSA with powders (SPJ and Questran® ointment) require 5min of mixing and two phases: the first phase to distribute the PA powder within the excipient and the second to homogenize the mixture. Homogeneity is obtained after 2min at 500rpm then 3min at 1000rpm for SSPSA composed of powders / fatty substances. For SSPSA without powder, homogeneity is achieved after 3min of mixing, at 1000rpm for the urea ointment and at 1500rpm for the starch glycerol cold cream. The first assay of the 50% SPJ was conclusive and confirmed by a second test with an accuracy of the content equal to 0.16% and 1.64% respectively.
The various tests made it possible to validate the mixing parameters for each of the SSPSA studied. Compliance of the assay for the 50% SPJ content was found to be conclusive and this assay is now put into routine. The PA are very satisfied with the mixer: reduction in repetitive movements and mixing effort, less washing and therefore saving of time. A notice has been created to facilitate the use of the new SSPSA packaging. A satisfaction survey must be carried out in order to collect the opinions of consumer services.