UPDATE 1-AstraZeneca sells rights to anaesthetics for up to $770 mln

* Aspen acquires non-U.S. rights to seven established drugs

* Latest in run of externalisation deals by AstraZeneca

* Aspen shares jump 10 percent, AstraZeneca stock slips (Adds context on externalisation drive, market reaction)

By Ben Hirschler

LONDON, June 9 (Reuters) - AstraZeneca has sold themarketing rights to a portfolio of anaesthetics for up to $770million in the latest so-called externalisation deal to raisefunds for investment in new drugs.

South Africa's Aspen Pharmacare will market theseven established medicines outside the United States under thedeal, which follows the sale of U.S. rights to the anaesthetics10 years ago to Abraxis, now part of Fresenius Kabi.

Aspen will pay AstraZeneca $520 million upfront and up to$250 million in sales-related payments, as well as double-digitpercentage trademark royalties, the companies said on Thursday.

Aspen Chief Executive Stephen Saad said it was an "excellentopportunity" for the South African firm and its shares jumped 10percent in Johannesburg. AstraZeneca stock fell 0.8 percent.

The agreement covers Diprivan, used for general anaesthesia,EMLA, a topical anaesthetic, and five local anaesthetics. Theanaesthetics, which are sold in more than a hundred countries,had sales in 2015 of $592 million.

AstraZeneca will continue to manufacture and supply theproducts on a cost plus basis to Aspen for an initial 10 years.

AstraZeneca has used externalisation income from licensingout products in non-core areas, such as neuroscience, to helpfund investment in new medicines in cancer and other fields.

Externalisation has helped underpin AstraZeneca's profits ata time it is facing a raft of patent expiries on previousblockbuster drugs, such as cholesterol fighter Crestor andheartburn medicine Nexium, but it has led to criticism about thequality of earnings from some analysts.

Externalisation deals contributed $1.1 billion to revenuelast year and the company has said the figure will be higher in2016. (Additional reporting by Paul Sandle; editing by David Clarke)