The present invention relates to the field of coating pharmaceutical substrates. In particular, the invention relates to methods of coating of pharmaceutical substances, pharmaceutical ingredients or a blend of them. The invention also provides a method of making a pharmaceutical formulation which may be processed into a pharmaceutical dosage form, which utilizes solid pharmaceutical particles and a pharmaceutical formulation obtained by the method. The methods of the invention utilize atomic layer deposition technology. The novel methods allow difficult, moisture sensitive and electrically charged pharmaceutical substrates to be easily processable.