Study Set Content:
Tears ph is about
7.4, with a range of 7 to
8 or slightly higher
It is generally thought that eye drops within a pH range of (blank) will not harm the cornea
4 to 10
Discomfort and a flow of tears will occur below pH
6.6
Discomfort and a flow of tears will occur below pH 6.6 and above pH
9
is probably
more acidic than the tear fluid
commonly used in pH
measurements.
Pure conjunctival fluid
pH increases rapidly when the
sample is removed for analysis
because of the loss of (blank)
from the tear fluid.
CO2
24-hour urine collection of a normal
adult has apH averaging about
6.0
units,
it may be as low as
4.5
or as
high as
7.8
When the pH of the urine is below normal values, hydrogen ions are excreted by the
kidneys
When it is above pH 7.4, hydrogen ions are retained by action of the kidneys in order to return the pH to its
normal range of values
Frequently used pharmaceutical buffers
a. Formulation of ophthalmic solutions
b. Colorimetric determination of pH
c. Research studies in which pH must be held constant
pharmaceutical solutions that are
meant for the application to delicate
membranes of the body should also
be adjusted to approximately the
same osmotic pressure as that of
the body fluids
Buffered Isotonic Solutions
colligative properties that measure
the concentration of the solutes
independently of their ability to cross
a cell membrane
Osmolality and Osmolarity
the concentration of only the solutes
that cannot cross the membrane
since these solutes exert an osmotic
pressure on that membrane
Tonicity
should be restricted solutions having
equal osmotic pressures with
respect to a particular membrane
Isotonic
solutions contains a higher
concentration of impermeable
solutes than the cytosol of the RBC:
shrinks/crenation
Hypertonic
contains a lesser concentration of
such solutes than the RBC cytosol
and fluid flows into the cells where
they swell and potentially burst
Hypotonic
isotonic solutions same osmotic
pressure as a specific body fluid like
blood and the body fluid of the eyes,
nose, bowel
Tonicity Measurement
products that require the same
tonicity with biologic fluids are
ophthalmic, nasal, parenteral and
some rectal preparations
