Sun, winner of 11 world titles, was cleared of wrongdoing in January by FINA, the international swimming federation.
FINA, the international swimming federation, confirmed in January that the swimmer had used a hammer to smash a vial containing his own blood sample.
Hosszu and Andrew claim two gold medals each on last day.
In men’s 1500m freestyle fastest heats, Romanchuk set a new World Cup record.
Campbell, meanwhile, was fastest (24.11) in the 50m freestyle final as she edged Michelle Coleman (SWE) 24.50, who won silver in an exciting finish.
Mohamed Mahmoud (58.14), Tameea Elhamayda (1:01.42) and M Al Khanji (1:08.78) of the host nation were also impressive alongside the elite swimmers.
The Qatari capital will host the FINA World Championships in 2023.
Last year, Abdulaziz reached the finals of 100m backstroke and 200m individual medley events.
17 Qatari swimmers to participate in the home event at Hamad Aquatic Centre.
The Qatari capital will also host the FINA World Aquatics Championships in 2023.
The court action follows an explosive report from FINA's own anti-doping committee in January saying Sun had used a hammer to smash a blood sample during an out-of-competition test in September last year.
Sarah Thomas, 37, could be seen in a video posted on Facebook arriving at Dover on the southern English coast with a group of supporters cheering her on.
The 21-year-old claimed silver at last month's world championships in South Korea
Lochte, 35, clocked 1min 57.76 to win a 27th national title and stamp himself a contender to make a fifth Olympic team next year.