Johnson & Johnson has reportedly dropped development of its neurotoxin Purtox, a much-hyped potential rival to Allergan's market leading blockbuster Botox.

The move to drop the wrinkle buster is designed to help the healthcare giant hone its focus on its breast aesthetics business, but will result in a small number of job loses in the US, according to media reports.

J&J snapped up the experimental neuortoxin through its acquisition of breast implant maker Mentor in 2009, but its development has been hit by delays ever since.

"Focusing on our core breast surgery business will allow us to expand successful programs, as well as increase our investments to develop additional new products to meet the needs of patients and the surgeons who care for them," a company spokesman told the Wall Street Journal.

But Brian Kinney, a clinical associate professor of plastic surgery at the University of Southern California in Los Angeles and a clinical investigator for the drug, told “Like many people, I am very disappointed as the clinical data was quite good and the opinion of the patients was favourable".