Our Lady of Fatima University
College of Pharmacy
Physical Pharmacy
BUFFERS AND ISOTONIC SOLUTIONS
1. Give the two pharmaceutically important inorganic buffers
Phosphate buffer system - This inorganic buffer is necessary for maintining
intracellular pH. Additionally, phosphate buffers have two main advantages. The
first is that they are very soluble in water, and the second is that they have an
exceptionally high buffering capacity. However, in other circumstances, these
gains may be countered by drawbacks. Since enzymatic reactions are inhibited
by phosphorus. Moreover, phosphate is an effective physiological buffer
because its pKa is close to physiological pH. It is comprised of dihydrogen
phosphate ions as the hydrogen ion donor (acid) and hydrogen phosphate ions
as the ion acceptor (base).
Protein buffer system - It aids in the regulation of acidity inside and outside
cells. It is composed of amino acids containing positively charged amino groups
and negatively charged carboxyl groups. Haemoglobin is an excellent buffer
because it binds to tiny amounts of acids in the blood before they may modify
the pH. Other proteins containing the amino acid histidine are also an effective
buffers.
2. Give the reasons for adjusting and buffering the pH of an ophthalmic preparation.
The pH of ophthalmic solutions can range from 4.5 to 11.5. However, certain
formulations is the reason why adjusting and buffering pH in opthalmic preparation
is required since chemicals with a high pH can potentially cause corneal injury if they
breach the surface of the eye. For example, when an opthalmic emergency develops,
such as a chemical eye injury, it is attributed to the eyes being exposed to an acidic
(pH 4) or alkaline (pH >10) fluid. Some ophthalmic solutions contain high doses since
it is regarded to improve medication performance, thus particular formulations are
developed to stabilize it, such as Proparacaine hydrochloride ophthalmic solution
(pH 3.5 to 6.0), which is commonly used as topical anaesthetic drops. Likewise,
antibiotic eye drop formulations incorporate HCl to alter pH.
3. Give the importance of isotonicity in pharmacy.
The significance of isotonic solution is that it enables cells to carry water and
nutrients in and out of the cells. This is vital for blood cells to accomplish their
purpose of distributing oxygen and other nutrients to other regions of the body. In
relation to pharmacy, there are pharmaceutical preparations that rely on these
specific mechanisms to successfully pose the efficacy of drug in the body and also to
prevent imbalance. In that way, isotonicity is beneficial in the field of pharmacy.
College of Pharmacy
Physical Pharmacy
BUFFERS AND ISOTONIC SOLUTIONS
1. Give the two pharmaceutically important inorganic buffers
Phosphate buffer system - This inorganic buffer is necessary for maintining
intracellular pH. Additionally, phosphate buffers have two main advantages. The
first is that they are very soluble in water, and the second is that they have an
exceptionally high buffering capacity. However, in other circumstances, these
gains may be countered by drawbacks. Since enzymatic reactions are inhibited
by phosphorus. Moreover, phosphate is an effective physiological buffer
because its pKa is close to physiological pH. It is comprised of dihydrogen
phosphate ions as the hydrogen ion donor (acid) and hydrogen phosphate ions
as the ion acceptor (base).
Protein buffer system - It aids in the regulation of acidity inside and outside
cells. It is composed of amino acids containing positively charged amino groups
and negatively charged carboxyl groups. Haemoglobin is an excellent buffer
because it binds to tiny amounts of acids in the blood before they may modify
the pH. Other proteins containing the amino acid histidine are also an effective
buffers.
2. Give the reasons for adjusting and buffering the pH of an ophthalmic preparation.
The pH of ophthalmic solutions can range from 4.5 to 11.5. However, certain
formulations is the reason why adjusting and buffering pH in opthalmic preparation
is required since chemicals with a high pH can potentially cause corneal injury if they
breach the surface of the eye. For example, when an opthalmic emergency develops,
such as a chemical eye injury, it is attributed to the eyes being exposed to an acidic
(pH 4) or alkaline (pH >10) fluid. Some ophthalmic solutions contain high doses since
it is regarded to improve medication performance, thus particular formulations are
developed to stabilize it, such as Proparacaine hydrochloride ophthalmic solution
(pH 3.5 to 6.0), which is commonly used as topical anaesthetic drops. Likewise,
antibiotic eye drop formulations incorporate HCl to alter pH.
3. Give the importance of isotonicity in pharmacy.
The significance of isotonic solution is that it enables cells to carry water and
nutrients in and out of the cells. This is vital for blood cells to accomplish their
purpose of distributing oxygen and other nutrients to other regions of the body. In
relation to pharmacy, there are pharmaceutical preparations that rely on these
specific mechanisms to successfully pose the efficacy of drug in the body and also to
prevent imbalance. In that way, isotonicity is beneficial in the field of pharmacy.
