FDA Warning Letter: Unofficial HPLC Injections, Shared Login

In short: FDA’s 2020 warning letter to Tender Corporation described HPLC injections missing from the records used for batch decisions, shared access to an infrared instrument, laboratory control issues, and weak complaint investigations. The case is a reminder to keep complete test records and investigate unexplained data and quality signals; its observations concern the inspected firm.

Background

FDA inspected Tender Corporation from November 12 to 25, 2019, and issued Warning Letter MARCS-CMS 599789 on July 23, 2020. The letter described several current good manufacturing practice (CGMP) findings at the firm. This article summarises the agency’s published account; it is not a finding about other manufacturers. (FDA Warning Letter to Tender Corporation, MARCS-CMS 599789, July 23, 2020)

Findings related to laboratory controls

HPLC injections and instrument access

FDA said that some HPLC sample injections were absent from the laboratory records used by the Quality Unit for batch disposition, including finished-product release. The firm could not adequately explain the injections. The letter cited 21 CFR 211.194(a), which requires laboratory records to include complete data from tests needed to assess compliance with specifications.

The agency also reported that laboratory employees used a shared login and password for an infrared spectrophotometer system. FDA said its access controls did not adequately prevent unauthorised alteration or deletion of raw electronic data. In response, the agency asked the firm for a system-wide assessment and remediation plan covering user privileges, administrative access, audit-trail review, and retention of laboratory data. These requests were specific to the warning letter. (FDA warning letter; 21 CFR 211.194(a), current eCFR)

Method performance and investigations

The letter described abnormal chromatographic peaks, missed integrations, and blank injections used between samples to address carryover. FDA also said the firm had not comprehensively investigated repeated system-suitability failures or established effective, timely corrective and preventive actions. The agency cited laboratory-control requirements in 21 CFR 211.160(b) and discussed the need for suitable methods and thorough investigations. The FDA’s 2018 data-integrity guidance explains the agency’s CGMP approach to reliable and accurate data; FDA guidance is nonbinding and does not replace the regulations.

Product complaints

FDA said several complaint investigations were closed without a supported root cause or effective corrective action. The letter identified complaints involving children who experienced blisters, rashes, or pain after using the firm’s topical products. FDA cited 21 CFR 211.198(a), which addresses written complaint procedures and Quality Unit review, including deciding whether a complaint needs investigation under §211.192. (21 CFR 211.198(a), current eCFR)

The warning letter also raised separate concerns about the approval status and labelling of certain products. Those product-specific findings are distinct from the laboratory-control issues discussed above.

Practical review points for QC teams

A useful review of an electronic test record can follow the sample from preparation through every instrument injection to the result reviewed for batch disposition. The site should be able to explain the treatment of repeat, aborted, excluded, or unusual runs and preserve the associated raw data and metadata. Staff access should be attributable, and the laboratory should have a defined way to review access rights and electronic changes. These are practical control themes reflected in the FDA case and guidance; each site must establish procedures suited to its systems and applicable requirements.

Example in-house criterion (not a pharmacopoeial requirement): Before a result is used for batch disposition, reconcile the instrument sequence and raw data files with the controlled test record; document and review the rationale and impact for any repeat, aborted, excluded, or unexplained injection.

For batch-associated production, control, or distribution records, retain records for at least one year after the respective batch’s expiry under 21 CFR 211.180(a). EU GMP Part I, Chapter 4, §4.11 (January 2011) requires batch documentation to be kept for one year after expiry or at least five years after QP certification, whichever is longer. Apply any longer period required by local law or the marketing authorisation. (21 CFR 211.180(a), current eCFR; EU GMP Part I, Chapter 4, §4.11, January 2011)

For related reading, see data integrity findings in FDA warning letters, the SOP on data integrity, good chromatography practices, and QC laboratory record maintenance.

Frequently asked questions

Does this letter establish a rule for every laboratory?

No. It reports FDA’s observations and requests to one inspected firm. Other laboratories must assess the regulations and guidance that apply to their operations.

Why did FDA object to the unofficial HPLC injections?

The letter said the injections were missing from the records used by the Quality Unit to make batch decisions. Under 21 CFR 211.194(a), laboratory records must contain complete data from required tests, including data generated by laboratory instruments.

Does the warning letter say every repeat injection is prohibited?

The letter does not present that as a general rule. It objects to injections that were not fully accounted for in the firm’s testing and batch records. A repeat or other non-routine run should be handled under applicable procedures, with its data and rationale available for review.

How long should batch-associated GMP records be kept?

At least one year after the respective batch’s expiry under 21 CFR 211.180(a). EU GMP Part I, Chapter 4, §4.11 also sets a five-year-after-QP-certification alternative for batch documentation, where that period is longer. Check the rule applicable to the product and market.

References

• U.S. Food and Drug Administration. Tender Corporation Warning Letter, MARCS-CMS 599789, July 23, 2020. Official letter.
• U.S. Food and Drug Administration. Data Integrity and Compliance With Drug CGMP: Questions and Answers, Guidance for Industry, December 2018. Official guidance.
• U.S. Electronic Code of Federal Regulations, current as of October 14, 2026: 21 CFR §§211.160(b), 211.180(a), 211.192, 211.194(a), and 211.198(a). Laboratory controls, retention, investigations, records, and complaint files.
• European Commission. EudraLex Volume 4, EU Guidelines for Good Manufacturing Practice, Part I, Chapter 4: Documentation, §4.11, January 2011. Official chapter.