The appropriate Ministers may by regulations provide, either in respect of medicinal products generally or in respect of medicinal products of a description or falling within a class specified in the regulations, that, subject to such exceptions as may be so specified, no person—
(a)being the holder of a product licence, or
(b)in the course of business carried on by him and consisting (wholly or partly) of manufacturing medicinal products or of selling medicinal products by way of wholesale dealing,
shall sell or supply any medicinal product to which the regulations apply to any person who does not fall within a class specified in the regulations.