| Abstract |
Gel systems have found extensive applications in the medicinal/pharmaceutical field because of their ease of preparation, ability for modifications, and responsiveness to external chemical or physicalstimuli. Gels usually act as hosts for active pharmaceutical agents for a variety of pathological conditions. They function as controllers of the release of pharmaceuticals that have proven to be “problematic” because they are either unsuitably insoluble to biological fluids, or they are metabolized unacceptably rapidly. Among the known bone diseases (osteoporosis, osteoarthritis, multiple myeloma, Paget’s disease and several others), the most challenging is osteoporosis, which burdens millions of people compromising patients’ quality of life. The recommended pharmaceutical treatment is the use of bis-phosphonates (BPs, a.k.a. “-dronates”). Etidronic acid (ETID) is the first osteoporosis treatment to enter the market (1977), while zoledronic acid is one of the treatments that followed (2007). Studies with N-containing BPs have shown that they are taken up by mature osteoclasts and inhibit farnesyl pyrophosphatase synthase, an enzyme of the mevalonate pathway. Their success in mitigating osteoporosis notwithstanding, these “-dronate” drugs present a number of challenges including limited bioavailability, fast excretion, and numerous side-effects, such as osteonecrosis of the jaw, hypocalcemia, esophageal cancer, ocular inflammation, atrial fibrillation, etc.. It is, therefore, imperative to design and fabricate “smart” systems that allow controlled delivery of the active BP agent, which will depend on the patient’s needs and idiosyncrasies. In this study, we report a detailed study on an easy-to-prepare a silica hydrogel-type DDS that can host and incorporate a variety of BPs. Several factors have been found to influence the controlled release of the active BP, such as cations present in the gel, active groups on the BP backbone, gel density, and temperature. These systems are intended for potential biomedical applications.
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Controlled release drug delivery systems for osteoporosis pharmaceuticals based on Silica hydrogels
