Buffer 101

Front 1

Is a solution of a weak acid and its salt or weak base and its salt that resists drastic changes in pH when small amounts of acid or basea are added to it.

Back 1

Buffer

Front 2

Buffers control the pH for the ff. Reasons:

Back 2

Chemical stability

Solubility of the drug

Patient's comfort

Front 3

Factors which can produce alterations of pH are:

Back 3

Alkali in certain inexpensive containers

Gases present in air such as CO2 and NH3

Front 4

Pairs of related chemical compounds capable of resisting large changes in pH of a solution caused by addition of small amount of acid and base

Back 4

Buffer systems

Front 5

Buffer systems are composed of a _____ and the ________of its conjugate base or a weak base and the salt of its conjugate acid

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Weak acid; salt

Front 6

When an ______ is added in the solution, the _____ member will react.

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Acid; basic

Front 7

When an ____is added in the solution, the _____ member will react

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Base; acidic

Front 8

Each component of the buffer pair will react with either acid or base to form the other component repressing the changes in ____ ion concentration

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H

Front 9

A selected buffer should not:

Back 9

Participate in oxidation-reduction reaction

Alter the solubility of other components

Form complexes with active ingredients

Front 10

Two inorganic buffer systems

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Phosphate buffer system

Borate buffer system

Front 11

Modified phosphate buffer system by the addition of NaCl to make it isotonic with _______ fluid

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Sorensen Buffer system; physiological

Front 12

Suitable for ophthalmic, nasal and external preparations

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Borate buffers

Front 13

Advantage: it can be used in solutions that contain metals that would precipitate in the presence of phosphates

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Borate Buffer system

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Disadvantage: _____ (when ingested) ; inefficient at physiological pH; supports _______

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Toxic; mold growth

Front 15

Three Primary Borate Buffer systems :

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▪️Feldman's Buffer system

▪️Atkin's and pantin buffer system

▪️Gifford buffer system

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Ph of Gifford Buffer system

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pH 6-7.6

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pH of Feldman's Buffer system

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pH 7.6-8.2

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pH of atkins and pantin buffer system

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pH 7.6-11

Front 19

Consists of an acid solution containing ____, _____) to make it isotonic), and an alkaline sokution containing ______.

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Feldman's Buffer system; boric acid, sodium chloride, sodium borate

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Disadvantage of fledman's buffer system

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Sodium borate is unstable

Front 21

Consists of an alkaline solution of _____ and an acid buffer solution of _____ and ______

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Alkin's and pantin buffer system; sodium carbonate, boric acid and sodium chloride.

Front 22

Disadvantage alkin's and pantin buffer system

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Too basic for most drugs

Front 23

Similar to feldman buffer system but in place of ______, _____ is added to make it _____

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Gifford buffer system; sodium chloride, potassium chloride, hypotonic

Front 24

Aka: Borax, sodium pyroborate, sodium tetraborate, tincal

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Sodium Borate

Na2B4O7. 10H2O

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Properties of sodium borate:

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Odorless and effloresce in warm, dry air

Soluble in water and glycerin

Insoluble in alcohol

Front 26

________ member of the borate buffer system

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Alkaline

Front 27

_______ borates are insoluble in water (except for alkali metals)

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Metal

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Sodium borate is ____, same with _____

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Toxic; boric acid

Front 29

Best eyewash when _____ enter the mucosa

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Acid

Front 30

Used in collyria

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1-2%

Front 31

Component in many mouthwashes and oral preparations

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Gifford buffer system

Front 32

Appliex in _____ to mouth ulcers

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Powder

Front 33

Weak ________ agent

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Bacteriostatic agent

Front 34

Forms ______ which serves as an ______ agent in cold cream and rose water ointment

Back 34

Borax soap; emulsifying agent