Animal & Veterinary

ANADA 200-168 CW 48 (Type A medicated article) - original approval

Approval Date: July 24, 1997





Equi Aid Products Inc.
1517 West Knudsen Dr.
Phoenix, Arizona, 85027

Generic Name:

pyrantel tartrate

Trade Name:

CW 48 (Type A medicated article)

Marketing Status:


Dosage Form: Type B medicated feeds (finished formulations) may be either dry feed mixtures or pelleted

How supplied: 50 pound feed bag

How Dispensed: Over-The-Counter (OTC)

Amount of Active Ingredients: 48 grams/lb

Route of Administration: Oral

Species: Horse

Labeled Dosage: 1.2 mg/lb (2.64 mg/kg) body weight once daily

Indications for use: For use in horses for:

  • the prevention of Strongylus vulgaris larval infections
  • the control of large strongyles (adults) - S. vulgaris, S. edentatus, Tridontophorus spp.
  • small strongyles (adult and fourth stage larvae) - Cyathostomum spp., Cylicocyclus spp., Cylicostephanus spp., Cylicodontophorus spp., Poteriostomum spp.
  • Pinworm (adult and fourth-stage larvae) - Oxyuirs equi
  • Ascarids (adults and fourth-stage larvae) Parascaris equorum

Pioneer Product: Strongid 48 (pyrantel tartrate), Pfizer Inc. (NADA 140-819)


Under provisions of the Federal Food, Drug, and Cosmetic Act, as amended by the Generic Animal Drug and Patent Term Restoration Act, (53 FR. 50460, December 15, 1988, First GAPTRA Policy Letter) an Abbreviated New Animal Drug Application (ANADA) may be submitted for a generic version of an approved new animal drug (pioneer product). New target animal safety data, drug effectiveness data, and human food safety data (other than tissue residue data) are not required for approval of an ANADA. An ANADA relies on the target animal safety, drug effectiveness and human food safety data in the pioneer's new animal drug application. Ordinarily, the ANADA sponsor shows that the generic product is bioequivalent to the pioneer. If bioequivalence is demonstrated through a clinical end-point study in food animals, then a tissue residue study to establish the withdrawal time for the generic product is also required. For certain dosage forms, the agency will grant a waiver from conducting an in vivo bioequivalence study (55 FR. 24645, June 18, 1990: Fifth GADPTRA Policy Letter; Bioequivalence Guideline, April 1990).

Bioequivalence Study

Title: Controlled Efficacy Study of the Bioequivalency of Strongid C1and Generic Pyrantel Tartrate Pellets in Horses.

1 Strongid®C is a trademark of and sponsored by Pfizer Animal Health, Division of Prizer, Inc., New York, NY

Test Facility/Study Director

Dr. Joe DiPietro (Study Director)
University of Illinois
College of Veterinary Medicine
2001 South Lincoln
Urbana, IL 61801

Generic Product Sponsor

Equi Aid Products, Inc.
1517 West Knudsen Drive
Phoenix, AZ 85027

Pioneer Product Sponsor

Pfizer Inc.
235 East 42nd St.
New York, NY 10017

Study Type and Purpose
This study was conducted for the purpose of determining if typical finished formulations of the pioneer and generic products (Strongid C for pioneer and Equi Aid generic pyrantel tartrate pellets) were bioequivalent. The bioequivalence determination was based on a in vivo clinical end-point, controlled anthelmintic study which was conducted as an GLP study at the University of Illinois. Both the generic and the pioneer products were pelleted and contained 4.8 grams of pyrantel tartrate per pound of pellets.

Experimental animals
At the initiation of the study, the study veterinarian determined the horses were free of any disease or condition that could interfere with the purpose or conduct of the study. Thirty horses with naturally acquired endoparasitic infections were utilized in this controlled efficacy study to evaluate the bioequivalency of Strongid C and generic pyrantel tartrate. Ages of horses on study ranged from 8 to 24 months.

Animals were randomly allocated into treatment groups in a parallel group design. Three horses were allocated to each of 10 replicates based on nematode and ascarid egg counts and fecal larvae culture results. Each replicate consisted of one horse per treatment group: placebo (or negative) control, positive control (reference/pioneer product), and the test generic product. Each pen housed one replicate. Group I horses were fed generic pyrantel tartrate pellets at a rate of 2.65 mg/kg (1.2 mg/lb) body weight mixed with 0.5 liter of oats once daily for thirty days, Group II horses were fed Strongid C pellets at a rate of 2.65 mg/kg (1.2 mg/lb) body weight mixed with 0.5 liter of oats once daily for thirty days, and Group III horses received only 0.5 liter of oats once daily for thirty days and served as negative controls. In addition to the 0.5 liter of oats all animals received alfalfa/grass hay in sufficient amounts to maintain body weight throughout the study. Water was available ad libitum.

Sample Collection
Fecal samples were collected and egg counts determined once during the acclimation period and on study days 0, 10, 20, and 29 (just prior to transportation of the horses to the necropsy facility). All horses were euthanized and necropsied on study Day 30. During necropsy, the stomach, small intestine, cecum, and colon were separated and the contents and mucosa screened for parasites by standard techniques. All endoparasites recovered were identified and enumerated: however, only the Strongylus edentatus and Parascaris equorum were used for the purposes of bioequivalence determination.

Results obtained demonstrated that pyrantel tartrate is effective in eliminating adult S. edentatus and adult and fourth-stage P. equorum (ascarids) from horses when administered on a daily basis at a dose of 2.65 mg/kg (1.2 mg/lb.) body weight. No significant difference (p> 0.05) in mean number of parasites recovered occurred between horses treated with generic pyrantel tartrate pellets and Strongid C.

No adverse reactions were observed in any of the treatment groups.

Bioequivalence of generic pyrantel tartrate pellets and Strongid C was established based upon a 95% confidence interval of the difference between the mean number of S. edentatus and P. equorum recovered from generic pyrantel tartrate pellets and Strongid C treatment groups. The efficacies of generic pyrantel tartrate pellets and Strongid C pellets are presented in Table 1.

TABLE 1 Efficacy of Generic Pyrantel Tartrate Pellets and Strongid C2

Species Controls3
Generic Percent
Strongid C2
Strongid C
Percent Efficacy3
Strongylus edentatus 48.24 5.30 89.01 3.22 93.32
Parascaris equorum
4.25 0.33 91.13 0 100.00
Parascaris equorum
0.69 0 100.00 0 100.00

2 Based on Geometric Means; Sum log10/N = Geometric Mean

3 Numbers in this column represent the antilog10 of the mean number of parasites collected at necropsy.

4 Percent efficiency = mean control - mean treated divided by mean treated times 100.


The drug is labeled: "Not for use in horses intended for food." Data on human food safety were not required for approval of this Abbreviated New Animal Drug Application.


This ANADA submitted under section 512(b) of the Federal Food, Drug, and Cosmetic Act satisfies the requirements of section 512 (n) of the act and demonstrates that pyrantel tartrate when used under its proposed conditions of use, is safe and effective for its labeled indications.


  1. Generic and Pioneer Labeling.

Copies of applicable labels may be obtained by writing to the:

Freedom of Information Office
Center for Veterinary Medicine, FDA
7500 Standish Place
Rockville, MD 20855

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