21 CFR § 522.1451 - Moxidectin microspheres for injection.
---
identifier: "/us/cfr/t21/s522.1451"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 522.1451 - Moxidectin microspheres for injection."
title_number: 21
title_name: "Food and Drugs"
section_number: "522.1451"
section_name: "Moxidectin microspheres for injection."
chapter_name: "FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES"
subchapter_number: "E"
subchapter_name: "ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS"
part_number: "522"
part_name: "IMPLANTATION OR INJECTABLE DOSAGE FORM NEW ANIMAL DRUGS"
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. 360b."
regulatory_source: "40 FR 13858, Mar. 27, 1975, unless otherwise noted."
cfr_part: "522"
---
# 522.1451 Moxidectin microspheres for injection.
(a) *Specifications.* The drug product consists of two separate vials. One vial contains 10 percent moxidectin microspheres and the second vial contains a vehicle for constitution of the moxidectin microspheres.
(1) Each milliliter (mL) of constituted suspension contains 3.4 milligrams (mg) moxidectin.
(2) Each mL of constituted suspension contains 10 mg moxidectin.
(b) *Sponsor.* See No. 54771 in § 510.600(c) of this chapter.
(c) *Conditions of use in dogs*—(1) *Amount.* (i) Using the suspension described in paragraph (a)(1) of this section, administer 0.05 mL of the constituted suspension per kilogram (kg) of body weight (0.023 mL per pound (lb)) as a single subcutaneous injection to provide 0.17 mg/kg body weight (0.0773 mg/lb).
(ii) Using the suspension described in paragraph (a)(2) of this section, administer 0.05 mL of the constituted suspension/kg of body weight (0.023 mL/lb) as a single subcutaneous injection to provide 0.5 mg/kg body weight (0.23 mg/lb).
(2) *Indications for use*—(i) *Suspension described in paragraph (a)(1) of this section.* For prevention of heartworm disease caused by *Dirofilaria immitis* in dogs 6 months of age and older; and for treatment of existing larval and adult hookworm (*Ancylostoma caninum* and *Uncinaria stenocephala*) infections.
(ii) *Suspension described in paragraph (a)(2) of this section.* For prevention of heartworm disease caused by *Dirofilaria immitis* for 12 months in dogs 12 months of age and older; and for treatment of existing larval and adult hookworm (*Ancylostoma caninum* and *Uncinaria stenocephala*) infections.
(3) *Limitations.* Federal law restricts this drug to use by or on the order of a licensed veterinarian.
[85 FR 4208, Jan. 24, 2020]