Author(s): Jay S, Fountain W, Cui Z, Mumper RJ
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Abstract Testosterone exhibits very low oral bioavailability because of its low aqueous solubility and extensive first-pass metabolism. The purpose of this study was to develop a novel bi-layer mucoadhesive wax-film composite (WFC), and to test the relative bioavailability of testosterone via the buccal route in rabbits. The release rate of testosterone from optimal WFCs (3/8-in. diameter) per unit surface area was 5.6 microg x cm(2) x mL(-1) x min(-1) and was zero-order. Bi-layer WFCs (average weight of 14 +/- 2.6 mg and thickness of 186 +/- 34 microns) containing 4 mg of testosterone were applied to the buccal pouch of anesthetized New Zealand white rabbits. Rabbits (n = 3) injected intravenously had C(max) and area under the curve values of 1200 +/- 46 ng/mL, and 48,227 +/- 12,995 ng x min/mL, respectively. Rabbits (n = 3) dosed via the buccal pouch had C(max), T(max), and area under the curve values of 127 +/- 13 ng/mL, 200 +/- 35 min, and 24,221 +/- 1543 ng x min/mL. The relative bioavailability for rabbits treated with the WFC was 50.2 +/- 3.2\% with a coefficient of variation of 6.4\%. It was concluded that these bi-layer mucoadhesive WFCs disks could deliver physiologically relevant amounts of insoluble drugs such as testosterone across the buccal mucosa. Copyright 2002 Wiley-Liss Inc.
This article was published in J Pharm Sci
and referenced in Clinical Pharmacology & Biopharmaceutics