Biomedical Engineering Reference
In-Depth Information
patients compliance and thus attaining higher adherence levels [4]. h ere
are many advantages of nanoparticles as drug carriers including high
stability, high carrier capacity, and feasibility of incorporation of both
hydrophilic and hydrophobic substances, feasibility of variable routes of
administration including oral administration and inhalation and reduc-
tion in dosing frequency [5]. Mainly uptake of nanoparticles occurs by
three mechanisms (1) transcytosis (2) intracellular uptake and transport
through the epithelial cells lining the intestinal, mucosa, (3) uptake via
peyer's patches [6, 7].
h ere are various routes of administration of drug delivery systems
as described above in Figure 14.1, which are advantageous in one or
another way.
1.
Oral drug delivery
-Most acceptable route for drug delivery,
substantial reduction in dosing frequency, economic and
ease of preparation [8].
2.
Implantable drug delivery-
High drug bioavailability and
least dosing frequency [8].
3.
Injectable drug delivery
-It also has high drug bioavailabil-
ity and least dosing frequency but painful procedure [8].
4.
Inhalable drug delivery-
Direct drug delivery to the target
site, reduction in dosing frequency and improved bioavail-
ability [8].
14.2 Dif erent Forms of Nanoparticles as
Drug Delivery
Nanoparticles are used in various forms for drug delivery such as nano-
spheres, nanoemulsions, nanocapsules, solid lipid nanoparticles, nanosus-
pensions, polymeric nanoparticles, liposomes and micelles, dendrimers
and niosomes. Monolithic nanoparticles (nanospheres) are those in which
drug is adsorbed, dissolved or dispersed throughout the matrix and nano-
capsules are those in which drug is coni ned to an aqueous or oily core sur-
rounded by shell like wall [9]. Nanoemulsions referred as miniemulsions or
sub-microemulsions by dispersing mainly oil in water. h ermodynamically
stable nanoemulsion (mean size 80.9 nm) of ramipril was developed for
oral administration. In vitro studies showed that drug release till 24h from
nanoemulsion band was much more important as compared to marketed
capsule formation and drug suspension [4]. h e relative bioavailability of
ramipril nanoemulsion to that of conventional capsule was 229.62% and to
