C. Markman et al., SLOW-RELEASE OF TETRACYCLINE HYDROCHLORIDE FROM A CELLULOSE MEMBRANE USED IN GUIDED TISSUE REGENERATION, Journal of periodontology, 66(11), 1995, pp. 978-983
THE OBJECTIVE OF THIS STUDY was to evaluate if the biologic membrane u
tilized for GTR can be impregnated by tetracycline hydrochloride and i
f the chemotherapeutic agent, once impregnated, can be released in min
imal. inhibitory concentrations for a period compatible with clinical
application. Initially, an in vitro study was done with cellulose memb
ranes cut in pieces measuring 9 cm(2). A volume of 100 mu l containing
a 72,000 mu g/ml solution of tetracycline was dispensed onto each fra
gment, and dried for 70 minutes at 37 degrees C. Four pieces measuring
0.5 cm(2) were cut from different points of the 9 cm(2) membrane (pre
sumably, containing 400 mu g of tetracycline), placed in test tubes co
ntaining 4 ml of sterile deionized water, and agitated for 2 minutes.
A standard curve was made from known concentrations of tetracycline an
d compared to 10 mu l of the test solutions obtained by the elution of
the 0.5 cm(2) fragments. The concentrations were determined through t
he bioassay technique in 3 duplicate experiments. The samples recovere
d from the membrane fragments had a mean of 101 mu g/ml of tetracyclin
e liberated, demonstrating that the membrane was impregnated homogeneo
usly by the chemotherapeutic agent. In a second phase, an in vivo stud
y was carried out to determine the length of time the drug was liberat
ed from the membranes and at which concentrations, in the presence of
an inflammatory process. Fourteen 0.5 cm(2) fragments containing 400 m
u g of tetracycline were placed in 14 polypropylene chambers containin
g 200 mu l of thioglycolate medium. The chambers were implanted in the
peritoneal cavities of 14 mice, one chamber per animal, and left in f
rom 1 to 14 days. They were then removed and the concentrations of tet
racycline determined from 20 mu l samples using a bioassay. The result
s showed that the antibiotic was released slowly from the Ist through
the 12th day in decreasing concentrations that varied from 218 to 20.8
mu g/ml. The impregnated cellulose membrane can probably be used in G
TR acting as a membrane and as a slow-release device, liberating the c
hemotherapeutic agent in concentrations high enough to eliminate perio
dontopathic microorganisms.