He said: 'What we're obviously not able to comment on are the actual, exact medical requirement that were in place because they are issues between doctor and athlete and it's a matter that UKAD are looking into.'
Damian Collins MP - the chairman of the Commons culture, media and sport select committee, which is also investigating the issue - said the whole matter 'looks odd'.
He added: 'People repeatedly asked the question, "What was in it?"
'Sir David Brailsford told the select committee that he had been told by the team doctor it was this drug called fluimucil, which is readily available in France and can easily be obtained and there are no restrictions on its usage.
'If it's as simple as that, why get a British Cycling coach to courier it from Manchester via London to Geneva when you could have just gone to a pharmacy in France and bought it over the counter?
'And that's why, I think, for a lot of people looking at this, it just looks odd.
'It doesn't look quite right. So can you just reassure us you've got the records and you know that it was all above board?'
Sir Bradley - the country's most famous and decorated cyclist - announced his retirement from the sport on Wednesday.
Fellow British cyclists Sir Chris Hoy, Chris Froome and Mark Cavendish all failed to react to the news via Twitter.
Sir Bradley, 36, won eight Olympic medals - a British record that included five golds - and was the first Briton to win the Tour de France in 2012.
He has denied any wrongdoing.