The deal excludes certain territories, primarily North America.
The generics company said it had identified anaesthetics as a key element of its expansion strategy into niche therapeutic categories that complement its existing operations.
The portfolio comprises five established medicines, which are sold in more than 100 countries including Japan, Brazil and Italy.
As part of its acquisition of the thrombolytic products Fraxiparine and Arixtra from GSK in 2014, Aspen also acquired an option to acquire the same products in certain countries to which GSK retained the rights, most notably China.
Separately, Aspen also announced the cancellation of collaboration with GSK in sub-Saharan Africa.
The cancellation of the collaboration, which generated about R2,1bn of gross revenue in Aspen 2015 financial year, will enable GSK to focus on its recently communicated strategic initiatives in Africa.
Aspen is retaining its existing African operations in Kenya, Tanzania, Nigeria, Ghana and Uganda and will also continue its exports into approximately 15 other African countries.
