Chemistry Reference
In-Depth Information
this purpose, and are found in the literature. Further, it has been reported that lipo-
somes can be covered with ligands to activate endocytosis in other cell types.
4.7.1 a
p p l I c aT I o n S
I n
d
r u g
d
e l I V e r y
Drugs are applied in various ways to treat illness. A drug designed to cure liver or
lung must reach its target with a suitable concentration. The main object is to treat
the illness in any particular organ, and the drug dosage is determined accordingly.
However, if the drug breaks down in the process of transport through the stomach,
etc., then other innovations are needed. In the following text, an example is given
where drug delivery is designed through the nasal pathway.
Inhalable drug delivery
: At present, there are many drugs that are applied through
the nasal pathway (inhalable drug delivery [IDD]). Besides small molecules (such as
hormones), even much larger molecules (such as insulin and other proteins) have been
reported as useful IDD systems. However, they need to meet certain critical demands:
Deliver the drug effectively and reach the lung
The particles (in the form of aerosols) need to be designed to achieve consis-
tent delivery
Surface-active substances, which are known to enhance penetration through the skin
barrier, also needs to be added. These should, of course, not cause any irritation in
the nose and other air pathways. Insulin is currently being marketed commercially
for IDD.
4.8
aPPlIcatIonS
4.8.1 d
I a g n o S T I c S
(I
m m o b I l I z e d
e
n z y m e S
o n
S
of l I d
S
u r f a c e S
)
In the past decade, extensive diagnostic instruments have become available to deter-
mine the state of illness control. For instance, the concentration of glucose (in the
case of diabetes control) in blood can be easily measured today by using a strip (size:
1 mm × 1 mm) covered with a suitable enzyme (glucose oxidase), which, in contact
with the blood sample, reacts (within 30 s) to produce degraded substances of glu-
cose (hydrogen peroxide). This enzyme is very specific to the degradation of glucose.
The reaction is calibrated to produce an electrical signal, and millimole per liter
(from 3 to 30 mmol/L) or milligram per liter glucose from a small drop of blood can
be safely measured. The preparation of the diagnostic strip requires an even layer
of the enzyme (or any other suitable chemical) on the test strip. It can be controlled
using the following surface chemistry principles:
Contact angle
Surface tension of the applied solution
Use of AFM to make image analyses
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