Biomedical Engineering Reference
In-Depth Information
bioavailability of the water insoluble (hydrophobic) drugs. Also GI fluid contains
a large number of degradative enzymes which can degrade the drugs leading to
the increased frequency of dose administration. To combat these problems, SLN
is used as a promising carrier for oral drug delivery as it offers many advantages,
such as protection of drugs from degradation in gastrointestinal tract, reduction in
gastrointestinal side effects of drugs and also masking the bitter taste of the drugs
(Fricker et al. 2012). Moreover, it is required to evaluate the stability of colloi-
dal carriers to assess their suitability for oral delivery because orally administered
drugs have to pass through the acidic-enzymatic milieu of GIT and because of this
reason peroral administration of SLN is restricted and intraduodenal route is pre-
ferred (Sarmento et al. 2007). But the rate and extent of absorption of SLN deliv-
ered orally is greater than the drug alone (Harde et al. 2011).
6.7.3 Intravenous Delivery
Although a wide range of anticancer drugs have been developed to treat different
kinds of tumours but their narrow therapeutic index and high hydrophobicity ren-
der them insoluble in most of the biocompatible media for intravenous injection
limiting their efficacy. So, selecting an appropriate carrier may help to transport
such payloads to a particular destination with proper protection from degradation.
In addition to this, the particles when injected intravenously are rapidly cleared
by liver and spleen which makes it difficult to introduce the drugs using this
route. Stealth SLN proves to be very effective in this case as these are taken up by
tumour cells via EPR effect. The polymer present over the surface of SLN which
may be polyethylene glycol, polyoxyethylene etc. renders the nanoparticles hydro-
philic and increase the circulation time in the blood by excluding them from RES.
When noscapine loaded SLN were pegylated and injected intravenously in mice
having brain tumour, half-life and retention time of noscapine was found to be
increased as compared to noscapine alone. Cellular uptake of Nos-PEG-SLN in
glioblastoma cells was more in comparison with Nos-SLN and Nos hence result-
ing in the greater accumulation at tumour site (Madan et al. 2013).
6.7.4 Intranasal Delivery
Nasal route is a very simple and non-invasive for systemic drug administration espe-
cially in case of gliomas where the drug cannot reach easily due to the presence
of blood brain barrier. In that case, nose to brain route helps the drugs not only to
bypass the blood brain barrier but to escape the hepatic first pass effect with less
systemic side effects. SLN loaded drugs can be readily delivered via intranasal route
as its hydrophilic shell interacts with the nasal mucosa and hence facilitates the
transportation across it. Moreover, SLN enables rapid accumulation of drugs, slow
and constant release rate of drug, low frequency of drug administration, much lower
doses and hence low therapy cost and better patient compliance (Joshi et al. 2012).
