A microdose of at least one active principle is homogeneously formulated as an ointment using a container with perforations having a size and shape that permit diffusion of the active principle(s) and petroleum jelly through the perforations, by: (a) weighing the at least one active principle in a container lined with a petroleum jelly; (b) encapsulating the active principle with additional petroleum jelly; (c) introducing the container with the active principle(s) and the petroleum jelly into a mixer, where the mixer contains at least one excipient in a heated liquid state; and (d) immersing the container within the at least one excipient in a heated liquid state, thereby melting the petroleum jelly, which causes diffusion of the active principal(s) and the melted petroleum jelly and microdoses the active principle(s) in the excipients.