Details from the study, which is being published in the Bulletin of the World Health Organization, appeared in Monday morning's editions of The Philadelphia Inquirer.
Critics have said drug donations have ranged from lifesaving gifts to mass dumping of old and unsellable products that still net the donors tax deductions.
The new study, led by Michael R. Reich, a Harvard professor of international health policy, reviewed 16,566 shipments between 1994 and 1997, going to 129 countries. The study team found that about 70 percent of the donated medicine met WHO guidelines for shelf life and were not due to expire for at least a year.
Among the 30 percent that did not meet WHO guidelines, 5.6 percent of the products had a shelf life of less than 100 days when shipped.
In a detailed examination of drug shipments to Haiti, Tanzania and Armenia, the study found that, although 50 percent to 80 percent of donated medicine appeared on the recipients' "essential drugs" list, between 10 percent and 42 percent did not.
The study was commissioned and financed by the Partnership for Quality Medical Donations, a group based in Berks County and representing seven pharmaceutical companies and six relief agencies. Members of the partnership include SmithKline Beecham, Wyeth-Ayerst Laboratories, Merck & Co. Inc., the Catholic Medical Mission Board, Project Hope and AmeriCares.
Reich said the sponsors did not review the team's article before its publication and every effort was made to limit their influence.
"The sponsors understood that the study needed to be conducted as an independent study in order for it to have credibility," he said.
James Russo, executive director for the partnership, said the study shows the importance of drug donations, "but there is no doubt we have to improve the donations, the relevance of them and the procedures through which the donations are made."
The consortium was formed two years ago after articles and letters appeared in medical journals complaining about unusable medical donations to countries in need.
The problems go beyond what drugs are sent, Reich said. Other issues include how to transport and distribute the supplies once they arrive, and keeping them out of the hands of unstable or corrupt local officials who may try to seize the supplies for their own profit.