In Japan, the compositions of crude drugs listed in the Japanese Pharmacopoeia are regulated.However, nonstandard or counterfeit crude drugs are often made using different plants or animals. Quality control of crude drugs is to confirm that the crude drugs have a certain level of bioactivity.The bioactivity of crude drugs is depended on the chemical components contained in the origin species of crude drugs. Therefore, in the quality control for crude drugs, it is important to identify whether original species is conformed to regulations.However, it is difficult to tell by the naked eye in a crude drug that is chopped or powdered.To solve this problem, molecular techniques have been used to identify the origins of crude drugs. For animal crude drugs, polymerase chain reaction (PCR) methods using species-specific primers have been applied.Direct sequencing methods using universal primers can target cytochrome b, cytochrome c oxidase I ribosome RNA genes.

The development of molecular techniques has enabled identification of the origin of  samples containing a mix of standard and nonstandard drugs. We reported a method for estimating the animal species included in mixed crude drugs using next-generation sequencing (NGS).Although this method is useful, it might not be used widely because NGS is expensive. If a device is inexpensive with accuracy, molecular examination techniques will likely be used widely.Recently,Oxford Nanopore Technologies developed a compact inexpensive NGS device called MinION. However, the accuracy of MinION base calling is lower than that of conventional NGS.If MinION could be used to analyze animal crude drugs, instead of conventional and expensive NGS, more advanced analysis would be used more widely. Therefore, to use MinION for identifying the animals in crude drugs,it is necessary to evaluate the accuracy of MinION base-calling.