GlaxoSmithKline, the pharmaceuticals multinational, has apologised after being accused of playing on the hardship of unpaid interns to recruit them to take part in clinical trials.

A marketing firm working for the FTSE 100 company sought to place a blog on careers advice websites boasting that involvement in drug trials could help graduates to finance their way through unpaid work placements.

In a proposed "guest blog" for the website Graduate Fog, an employee at TouchPoint Digital, working on behalf of GSK, wrote: "Clinical trials could be your solution."

A spokesman for GSK told the Observer the behaviour of the marketing company had been "unacceptable" and that it was no longer working with the firm. TouchPoint, of Cambridge, had contacted Graduate Fog with the suggestion of an "informative article about ways to earn money while job hunting, ie temporary solutions when struggling financially", targeted at those who could not afford to take an unpaid internship.

The proposed article read: "Having a degree is fantastic, but that doesn't mean much to start with if you don't have work experience. Internships can be very valuable by giving you a step on that career ladder, but today most are unpaid. I did an unpaid internship for 3 months, and had a part-time job as well in order to support myself.

"However, perhaps you won't have time for both jobs and would prefer an immediate income to tide you over for the coming months. Clinical trials could be your solution. Depending on the length of the study, you could earn up to £2,000 per trial for up to 4 trials a year, plus reasonable travel expenses."

Touchpoint provided examples of similar articles previously published on websites targeted at students. In an email to the founder of Graduate Fog, Tanya de Grunwald, it added: "Your readers would also benefit if there is a small link at the end of the article to the GSK website, which is the biggest pharmaceutical company in the UK, so that if they want to find out more or get answers to more specific questions they can do so."

De Grunwald said she rejected the article as "not just crass [but] downright irresponsible".

GSK said it did not usually "specifically target young people in ads for clinical trial participants or approve of the use of inducements to recruit subjects of any age". It added: "In this specific case, the agency was asked to create a general advertisement for clinical trial enrolment. We're no longer working with the agency.

"The tone used here is wrong. It trivialises the role of clinical trials in developing new medicines and the part our volunteers play in that process. This isn't acceptable and we're looking into what happened."