One of the main promising directions in the development of pharmacology is the development of drugs that provide targeted drug concentration and effective approaches to obtaining them using nanoscale drug delivery systems. In our opinion, the most promising is the use of biodegradable delivery systems due to their low toxicity and xenobiotic effects on the patient’s body. The need to develop regulated drug delivery systems is due to their clear advantage over analogues in standardized dosage forms. Based on modern research publications we have developed an exosomal antibacterial form of azithromycin that has pronounced selective properties for respiratory epithelial cells. The aim of the work was to study the safety parameters of the developed drug based on exosomal particles, in particular subchronic toxicity. For the study 3 experimental and 1 control groups of white rats weighing 190-220 g were formed with 10 heads each. The drug was administered intragastrically daily for 90 days in doses of 1/10; 1/20 and 1/50 of the LD50 set in the acute experiment. The study found that the use of the developed exosomal drug intragastrically once a day for 90 days does not affect the behavioral responses of animals and their external condition.