dihydrazide with the aldehyde groups on the polymer chains with three dimensional cross linking the reaction is run at acid ph e g between about 4 0 to about 6 0 in order to speed the gel formation and to prevent reaction of amino groups of the active ingredient the active ingredient is thus trapped within the resulting polymer matrix shortly after mixing the components the solution suspension is injected installed in an animal or human patient the matrix solidifies in situ within several minutes e g usually within about 5 minutes the hydrated polymer matrix degrades in vivo and is therefore resorbable by the body unlike polyesters no acid is produced as a result of resorption non reactive polymers may be included to after the diffusional resistance or to complex the bioactive agent 1 non toxic 2 resorbable 3 versatile as to molecular size and chemical nature of the bioactive agent 4 no requirement for exotic components that are expensive or difficult to obtain 5 controllable release rate 6 producible according to gmp at reasonable cost 7 sterilizable disclosed herein are polysaccharide drug delivery matrices and the methodology for producing and using the same more specifically the polysaccharide drug delivery matrices of the present invention may be derived from periodate oxidized dextran and dihydrazides the cross linking reaction is carried out at acidic ph which allows entrapment of bioactive substances with free amino groups protonation of the amino groups in the ph range of 4 6 renders such groups relatively unreactive as compared to the dihydrazides hence the bioactive agent remains intact and does not.