21 CFR § 343.13 - Rheumatologic active ingredients.

---
identifier: "/us/cfr/t21/s343.13"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 343.13 - Rheumatologic active ingredients."
title_number: 21
title_name: "Food and Drugs"
section_number: "343.13"
section_name: "Rheumatologic active ingredients."
chapter_name: "FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES"
subchapter_number: "D"
subchapter_name: "DRUGS FOR HUMAN USE"
part_number: "343"
part_name: "INTERNAL ANALGESIC, ANTIPYRETIC, AND ANTIRHEUMATIC DRUG PRODUCTS FOR OVER-THE-COUNTER HUMAN USE"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "21 U.S.C. 321, 351, 352, 353, 355, 360, 371."
regulatory_source: "63 FR 56814, Oct. 23, 1998, unless otherwise noted."
cfr_part: "343"
---


# 343.13 Rheumatologic active ingredients.

(a) Aspirin.

(b) Buffered aspirin. Aspirin identified in paragraph (a) of this section may be buffered with any antacid ingredient(s) identified in § 331.11 of this chapter provided that the finished product contains at least 1.9 milliequivalents of acid-neutralizing capacity per 325 milligrams of aspirin as measured by the procedure provided in the United States Pharmacopeia 23/National Formulary 18.