The European Commission's Maroš Šefčovič has said it is "time to get medicines across the finish line" after holding talks with Lord Frost about the Northern Ireland Protocol.
Mr Šefčovič had previously said it was his top priority to agree a deal to guarantee the supply of medicines from Great Britain to Northern Ireland.
He added that "strong political will" was needed to advance on other issues.
UK Brexit Minister Lord Frost said the progress had "been quite limited".
"The gap between our positions is still significant," he said.
"There has been some potential convergence on the medicines issue but agreement has not been reached."
Lord Frost said the UK's position remained that it would use Article 16 of the protocol, which would suspend parts of the deal, if solutions could not be found on the issues being negotiated.
The two men will speak again next Friday.
The protocol was agreed by the UK and EU in October 2019 as a way to avoid a hardening of the Irish land border.
It leaves Northern Ireland in the EU's single market for goods, meaning goods can flow freely with the Republic of Ireland.
However, goods arriving into Northern Ireland from the rest of the UK are now subject to checks and control, amounting to an "Irish Sea border".
The EU has proposed reforms to improve the operation of the protocol.
However, the UK wants more fundamental change, including removing the European Court of Justice from an oversight role.
On Wednesday, Mr Šefčovič suggested the EU could act unilaterally to guarantee the supply of medicines from Great Britain to Northern Ireland.
The EU brought forward proposals earlier this year which it said would tackle the medicines issue.
Mr Šefčovič said: "I would 100% prefer if we can present this good solution as a joint approach.
"But I'm fully conscious of time.
"I have to be very, very clear that we are ready to move on our own if it's not possible at this stage to push on a joint approach."
The UK is continuing to threaten the use of the Article 16 mechanism if agreement cannot be reached on all protocol issues.
It allows parts of the deal to be unilaterally suspended if they are causing serious problems or leading to diversion of trade.