Biomedical Engineering Reference
In-Depth Information
leuprolide acetate for palliative treatment of advanced prostate cancer for a one-,
three-, four-, or six-month treatment period, while Atridox
®
is used to deliver
continuous doxycycline in the treatment of chronic periodontitis for a period of
seven days. A promising result of injecting non-polymeric organogel was also seen
in an
in vivo
evaluation of controlled release of contraceptive steroids from an
organogel made up of polyglycolyzed apricot kernel oil and glyceryl palmitostearate
[33]. It was demonstrated that the organogel
in situ
implant was effective in blocking
the estrous cycle of rats for a prolonged period of 35 consecutive days as compared
to 4 consecutive days in rats receiving oil formulation.
Recently, Bastiat and co-workers reported that an injectable organogel system
based on safflower oil and
N
-behenoyl l-tyrosine methyl ester was able to deliver
rivastigmine, an acetylcholinesterase inhibitor, for several weeks [41]. Hence, this
preparation could possibly be an alternative treatment option for non-compliant
patients with Alzheimer's disease. It has been reported that such an
in situ
forming
implant is well tolerated and biocompatible [42-45]. The initial acute inflammatory
response at the administered site is in line with the normal physiological immune
response to foreign bodies and the wound healing process following injury.
The inflammation and characteristic infiltrates would subside to a minimal level
within two weeks [33, 41]. Furthermore, the shortcomings of burst effect and
possibility of particulate migration to other sites as observed in microsphere
delivery system were overcome by parenteral organogel formulation [46-50].
Moreover, the manufacture of a large-scale, reproducible and sterile organogel is
much easier than the manufacture of a microsphere system [47, 48].
3.3.3
Oral Formulation
The concept of edible organogels has led to many potential applications in the
nutraceutical and pharmaceutical industries, and even extends to technological
improvements in food manufacture [51]. Organogels as an oral formulation offer
the possibility of sustained and controlled release of lipophilic drugs. It was shown
that when ibuprofen, a model lipophilic compound, was orally administered to rats
in an aqueous suspension form, the ibuprofen concentration in plasma rapidly in-
creased and then disappeared from the body. In contrast, when administered in an
organogel formulation, the prolonged release from the gel matrix resulted in rapid
absorption being suppressed, and
t
max
was significantly delayed, which synergisti-
cally enhanced the bioavailability of the ibuprofen [52]. Many lipid-soluble phyto-
chemicals derived from plants are found to have therapeutic and health-promoting
effects. However, beneficial effects of many of these bioactive compounds are not
delivered to the patients simply because of lowwater solubility and poor bioavailabil-
ity of the compounds. Yu and co-workers recently developed a food-grade organogel
using monostearin, a GRAS (generally recognized as safe) organogelator, which
achieved high bioaccessibility and loading of curcuminoids [53].
Application of orally administered organogel has been extended to a veterinary
study, where chickens were vaccinated against Newcastle disease via raw rice
Search WWH ::
Custom Search