Any person authorized by the board of pharmacy is hereby given the right of entry for inspection during normal business hours upon all open premises purporting or appearing to be used by a wholesale drug distributor or pharmacy distributor in Missouri. Any wholesale drug distributor who provides adequate documentation of the most recent inspection less than two years old by the Food and Drug Administration or other comparable state agency as determined by the board with a satisfactory rating shall be exempt from further inspection by the board of pharmacy. Such an exemption shall not bar the board of pharmacy from initiating an investigation pursuant to a public or governmental complaint received by the board of pharmacy regarding a wholesale drug distributor not licensed by the Food and Drug Administration.