asked Her Majesty's Government:
Whether manufacturers of licensed organophosphate sheep dips are required to notify the licensing authorities of any changes they make in the trade formulation of their products; and, if so, whether any such notifications were received between 1985 and 1994; what they were; and what reasons were given for any changes.
All changes in formulations to authorised veterinary medicinal products must be notified in advance to the Veterinary Medicines Directorate (VMD) and are subject to scrutiny for authorisation. The active ingredient of every organophosphorus sheep dip is shown on the label of the product. Phenols were voluntarily withdrawn by manufacturers from sheep dip products following a review by the Veterinary Products Committee (VPC) in 1992. The reasons for the withdrawal of phenols are a matter for the companies concerned. It is likely that they were withdrawn because there was considered to be insufficient return from the market to justify the research needed to satisfy the further requests for data made by the VPC. Details of other changes in formulation could be identified only at disproportionate cost.