1. To a manufacturer or wholesaler who has been issued permits pursuant to this chapter;

2. To a licensed pharmacist, permitted pharmacy or a licensed practitioner of medicine, osteopathy, podiatry, dentistry or veterinary medicine;

3. To a person who has been issued a controlled substance registration certificate pursuant to § 54.1-3422, if the certificate of such person authorizes such purchase;

4. On a special written order accompanied by a certificate of exemption, as required by the federal laws, to a person in the employ of the United States government or of any state, territorial, district, county, municipal, or insular government, purchasing, receiving or possessing drugs by reason of his official duties;

5. To a master of a ship or a person in charge of any aircraft upon which no physician is regularly employed, for the actual medical needs of persons on board such ship or aircraft when not in port. However, such drugs shall be sold to a master of such ship or person in charge of such aircraft pursuant to a special order form approved by a commissioned medical officer or acting assistant surgeon of the United States Public Health Service; and

6. To a person in a foreign country in compliance with the provisions of the relevant federal laws.