This study aimed to determine the therapeutic equivalence of four multi-source drugs containing moxifloxacin (400 mg tablets) in vitro studies to establish their interchangeability with the reference product. Four multi-source products were acquired in pharmaceutical establishments in metropolitan Lima, each from different manufacturing sites (two products from India, one from Brazil, and one from Peru). The reference product was Avelox (400 mg) coated tablets (Bayer AG, Germany). Quality control and dissolution profile tests were performed. For dissolution tests, a validated ultraviolet-visible spectrophotometry method was used to determine the percentage of drug released. The similarity factor (f2) analysis was used to establish therapeutic equivalence of the drug release curves. The dissolution rates were considered equivalent if the values of f2 were between 50 and 100. Concerning the quality control tests, the moxifloxacin content was 98.5% in the reference product and 97.1–100.0% in the multi-source products. Three out of four multi-source products passed the f2 test at pH 1.2. Therefore, there is at least one moxifloxacin multi-source product circulating in Peru, manufactured in India, that does not is not interchangeable with the reference product.