Androgens in Health and Disease.pdf - E Library

Chapter 8/Androgen Pharmacology and Delivery Systems 141
8 Androgen Pharmacology
and Delivery Systems
Christina Wang, MD
and Ronald S. Swerdloff, MD
CONTENTS
INTRODUCTION
PHARMACOLOGY OF ANDROGENS
ANDROGEN PREPARATIONS AND DELIVERY SYSTEMS
SELECTION OF THE ANDROGEN DELIVERY SYSTEM
ACKNOWLEDGMENT
REFERENCES
INTRODUCTION
Historically, testis extracts from animals and then men were used as a rejuvenation
mixture with poor success. Testosterone was first synthesized in the 1930s, providing
for the first time a means to provide sufficient testosterone to treat hypogonadal men.
Initially, testosterone pellets were developed for subcutaneous implant and the methyl
derivative (methyltestosterone) was administered as an orally active agent. In the
1950s, the testosterone esters (propionate, enanthate, and cypionate) became available
and have continued to be used for testosterone-replacement therapy in androgen
deficiency (1–4). During the peak era of steroid chemistry, modifications of the testosterone
molecule were made to achieve orally active bioactivity and for the “anabolic”
effects such as increased nitrogen retention, muscle protein synthesis, muscle
strength, and mass. Methyltestosterone and fluoxymesterone were prescribed as oral
preparations for hypogonadism, but the former was criticized for its hepatotoxicity
and the latter was a weak androgen. In the 1970s, oral testosterone undecanoate was
marketed with wide acceptance in Europe, Australia, and Asia but was not available
in the United States. In the past 10 yr, there has been a resurgence in the interest of
development of new formulations and delivery systems of testosterone for potential
new indications such as androgen replacement in elderly men, male contraception,
severe wasting diseases, and androgen replacement in gonadectomized or postmenopausal
females.
From: Contemporary Endocrinology: Androgens in Health and Disease
Edited by: C. Bagatell and W. J. Bremner © Humana Press Inc., Totowa, NJ
141