Pharmacy Teacher

column contains the chromatographic packing material needed to effect the separation. This packing material is called the stationary phase because it is held in place by the column hardware. A detector is needed to see the separated compound bands as they elute from the HPLC column [most compounds have no color, so we cannot see them with our eyes]. The mobile phase exits the detector and can be sent to waste, or collected, as desired. When the mobile phase contains a separated compound band, HPLC provides the ability to collect this fraction of the eluate containing that purified compound for further study. This is called preparative chromatography

HPLC:
An injector [sample manager or autosampler] is able to introduce [inject] the sample into the continuously flowing mobile phase stream that carries the sample into the HPLC column.

Mobile Phase in HPLC:
A reservoir holds the solvent [called the mobile phase, because it moves]. A high-pressure pump [solvent delivery system or solvent manager] is used to generate and meter a specified flow rate of mobile phase, typically milliliters per minute

The components of a basic high-performance liquid chromatography [HPLC] system are shown in the simple diagram

ref:
https://www.waters.com/waters/en_US/How-Does-High-Performance-Liquid-Chromatography-Work%3F/nav.htm?cid=10049055&locale=en_US

Current Good Manufacturing Practice for Finished Pharmaceuticals established requirements concerning the expiration date on a drug product and stability testing to assure the appropriateness of that date. Each drug product may be a unique article because of, for instance, differences in (1) chemical and physical properties of the active ingredients or the excipients, (2) manufacturing procedures, (3) formulations, (4) containers and closures, (5) proposed storage conditions, and (6) the stability of the article to maintain its quality or purity through the use of antioxidants or preservatives. Because of the uniqueness of each drug product, it is virtually impossible to provide one set of rules that can apply to all situations. The CGMPs were purposely written broadly to allow for such unique differences.
Reference
https://www.fda.gov/ICECI/Inspections/InspectionGuides/InspectionTechnicalGuides/ucm072919.htm