Biomedical Engineering Reference
In-Depth Information
organs and tissues such as lipases can degrade the lipid structure. Therefore it is
very important to select an appropriate route for SLN administration. Initially
SLN were prepared for parenteral delivery of drugs but nowadays SLN has been
delivered in the body through different routes (Severino et al. 2013). In one study,
etoposide loaded tripalmitin nanoparticles were developed to evaluate the effect
of administration route. The nanoparticles were injected via subcutaneous, intra-
venous and intraperitoneal routes in mice having Dalton's Lymphoma tumour and
out of these three routes investigated, highest tumour uptake and sustained release
of the drug was observed in subcutaneous injection resulting in better cancer
relapse (Reddya et al. 2005).
Varshosaz et al. studied the biodistribution of amikacin loaded SLN in male
wistar rats bearing cystic fibrosis infections. These nanoparticles were injected via
pulmonary and intravenous route to determine the accumulation rate in the lungs
and kidneys. Higher drug concentration in the lungs and lower accumulation in
the kidneys avoiding nephrotoxicity was observed after pulmonary administration
than intravenous injection. Therefore the route of administration depends upon the
disease and site to be targeted. Some of the drug delivery routes utilized in the
cancer therapy are as follows.
6.7.1 Topical Drug Delivery
SLN is highly effective and efficient drug carrier for topical drug applications espe-
cially in case of skin cancers such as basal cell carcinoma and squamous cell car-
cinomas. It enhances the intracellular concentration of drug as well as reduces the
cytotoxity of skin chemotherapy (Üner and Yener 2007). For topical drug delivery,
it is essential to incorporate the SLN dispersion in some suitable dermal carriers like
creams or gels in a particular proportion so as to obtain the required consistency for
dermal applications as SLN containing 40 % lipid has found to possess comparable
elastic properties to standard dermal preparations (Lippacher et al. 2004).
It has several advantages over the oral or intravenous administration, such as ease
of application, negligible skin irritation, controlled release and prevention of first pass
metabolism. These nanocarriers have about 15 times more occlusivity than micropar-
ticles which leads to the enhanced hydration of stratum corneum and reduced pack-
ing of corneocytes, thus facilitating the drugs deeper into the skin layers. Sonali bose
et al. has described that higher amount of quercitin localized within the skin when
administered using SLN as compared to quercitin alone (Bose et al. 2013).
6.7.2 Oral Drug Delivery
Oral route is the most common, safe and favourable for drug delivery because of
its easy administration which enhances the patient's compliance and hence thera-
peutic success. Despite these advantages, oral delivery is obscured because of the
hydrophilic environment of the gastrointestinal tract (GIT) resulting in limited
