combining a conjugate acid/base pair
How do we make buffers?
Buffer Capacity
the measurement of how well a buffer resists pH change.
pH=pKa
When do buffers have the greatest buffering capacity?
Dilution
causes change in activity coefficients
Temperature
causes changes in Kw
addition of electrolytes
changes ionic strength of the solution
false; activity coefficients not taken into account
The calculated pH of the buffer equation is always the same as the experimental value. T/F?
If false, explain why.
oral or parenteral
Borate buffer cannot be used to stabilize what type of solution(s)?
low
What kind of buffer capacity do you want for drugs that will be administered to humans?
buffer capacity is low, volume & buffer capacity of physiologic fluid is large compared to volume administered, volume administered is small
Tissue irritation, due to large pH differences between the solution being administered and the physiologic environment in which it is used, will be minimal when
A
You want to prepare a buffer solution of pH 7.4. Which pair would be better for the preparation of the buffer?
A. Monobasic phosphate/dibasic phosphate (pKa=7.21)
B. Acetic acid/ sodium acetate (pKa=4.76)
C
You want to prepare a buffer with a larger buffer capacity. Which pair would be better?
a. NaH2PO4 (0.1M) + Na2HPO4 (0.1M)
b. NaH2PO4 (0.2M) + Na2HPO4 (0.2M)
c. NaH2PO4 (0.3M) + Na2HPO4 (0.3M)
A
If you want to prepare an eye drop using acetate buffer (pKa=4.76) of pH 4.5, which would be better?
a. Acetic acid (0.001 M) + sodium acetate (0.001 M)
b. Acetic acid (0.01 M) + sodium acetate (0.01 M)
c. Acetic acid (0.1 M) + sodium acetate (0.1 M)
A
When an eye drop should be formulated in a buffer of pH 4.5, the drug product needs to have a preferred dose of ______ to minimize tissue irritation.
a. 1 gtt
b. 2 gtt
c. 3 gtt