balanced ph , hyperosmotic , hypoosmotic , or isoosmotic gels are ideal vehicles for drug delivery . they are especially suited for topical body cavity or injection application of drugs or diagnostic agents ; for drug or diagnostic agent delivery to the eye of a mammal ; as protective corneal shields ; or as ablatable corneal masks useful in laser reprofiling of the cornea . the compositions without the addition of a drug or diagnostic agent are useful as medical devices , for instance , in separating surgically or otherwise injured tissue as a means of preventing adhesions .