Adsorption

What is a LAKE?

- A lake is a straight color closely bound to substrate (adsorbent) to form an INSOLUBLE pigments.

What is Kaolin USP? What is Attapulgite USP?

- A native hydrated aluminum silicate (adsorbant and drying agent) - Attapulgite is a highly treated, processed, native magnesium aluminum silicate. It is moderately viscous whereas colloidal is purified and is viscous.

What is a therapeutic application of adsorbents?

- Adsorbents are chemically INERT capable of adsorbing gases, toxins, and bacteria. These powders are in fine particles to increase surface area and can be effectively used for GI detoxification and adsorption of gases resulting from abnormal intestinal fermentation.

How does color fading in tablets appear?

- Color fading in tablets may appear as spotting and speckling.

Name the application of each lake. - FD&C and D&C lakes - External D&C lakes Lakes are _____ in water and organic solvents.

- Coloring the coatings of tablets - Externally applied drugs - insoluble

Decoloration. How is is done and using what?

- Decoloration is a process of depriving solutions of color by use of appropriate adsorptive medium. This is used for removal of coloring matter. Animal, wood or activated charcoal are frequently used as decolorizing agents. Also clays such as bentonite and kaolin are used.

What is a negative effect of adsorption?

- Drugs could be less effective due to its adsorption on the surface of solids such as the adsorption of potent drugs on the walls of IV administration sets.

Lake particles impart an even and uniform color to _____ product mixes that cannot be obtained from the organic colors in their pure state.

- Dry

What is the dose of activated charcoal given?

- It is recommended in a dose by weight that is 10 times the weight of the estimated drug or poison ingested. Max of 100 grams in adults. - For medication ingestions, single-dose activated charcoal is the modality of choice for gastrointestinal decontamination. Can generally be used up to 1 HOUR after ingestion of a potentially toxic amount of medication. *Note that there is no indication for Ipecac syrup in a healthcare setting.

What did the application of Attapulgite used to be?

- It used to be use in Kaopectate. Now bismuth subsalicylate is used as the adsorbent to adsorb bacterial toxins.

What is a miscellaneous use of adsorption?

- Removal of objectionable odors from room. - Operation of gas masks

Desorption

- Removal of the adsorbate from the adsorbent.

Activated Charcoal USP:

- Residue from the destructive distillation of various organic materials such as wood and treated to increase its adsorptive power. It is VERY VERY VERY fine particles and has a surface area of 100m^2 per gram. - It is employed to adsorb organic intoxicants and GI gases (Emergency intoxication treatment for virtually all drugs and chemicals) - Do not co-administer with IPECAC syrup.

What is Adsorption chromatography?

- Solutes are retained in the column as a result of the ability of the stationary phase (adsorbent) to bond temporarily to its active surface the different constituents in the solution. - HPLC or high preformance liquid chromatography is used to speed up this time consuming process.

Surface area of a powder is determined by?

- The mass of gas adsorbed per gram of adsorbent.

FD&C 3 means what?

- There are 3 colors.

- Most dye are relatively _____ chemicals due to their unsaturated structures.

- Unstable

Drugs are ______ by a tissue or organ and ________ by a membrane, enzyme or cell wall.

- absorbed - adsorbed

- Taking up water by a sponge is _________. - capturing of a toxicant on the surface of activated charcoal is _______.

- absorption - adsorption

A solid immersed in a solution containing several dissolved substances may selectively remove or _____ one or more solute by capturing it on its surface, thus accumulating it at the solid/liquid interface.

- adsorb

Increasing temp and decreasing pressure can lead to greater _______.

- desorption.

Adsorption is an _______ process reducing energy whereas desorption is an ________ process.

- exothermic - endothermic

Adsorption of materials onto a solid surface can take place either from a ____/_____ or from _______.

- gas/vapor - solution

Langmuir equation: what are the two assumptions?

1) The solid surface contains uniform adsorption sites or active sites, each capable of adsorbing one gas molecule. only the molecules adsorbing empty sites can be adsorbed. (only monomolecular or one molecule thick) 2)negligible forces of interaction b/w adsorbed molecules.

What are the two types of adsorbents?

1) hydrophilic (metals, silicates, metal oxides). These have exposed polar groups and make GOOD adsorbents. 2) Hydrophobic (carbon, sulfur, teflon) these are non polar and have vander waal forces repelling.

The extent of adsorption is determined by??? List 4.

1) strength of interaction (depends on the chemical nature of both adsorbent and adsorbate) 2) surface area of adsorbent 3) temperature 4) partial pressure of adsorbed gas for gas adsorption only.

What is the difference between adsorption and absorption?

Adsorption is a SURFACE EFFECT whereas absorption is the accumulation and distribution of a substance throughout the absorbing medium.

True or false. In vapor adsorption, Physical adsorption is irreversible and chemical adsorption is reversible.

False. Physical adsorption is reversible (weak) and Chemical is irreversible (stronger)

Freundlich equation

General and somewhat empirical equation for vapor adsorption. It states that at low pressure extent of adsorption is directly proportional to p^1 and high pressure adsorption is independent of p^0. Plotting the equation gives linear line if you take log of both sides.

Adsorption of surfactants:

Plateau of graph indicated either maximum adsorption or micelle formation (critical micelle concentration)

Adsorption

The process of concentrating a compound at the interface.

How is adsorption used in vaccinations?

Toxoids or detoxified toxins such as Diptheria Toxoid USP are adsorbed to adjuvants (solid material) in order to keep them in the body for longer periods of time.

True or false. Adsorption from solution is generally more complex than adsorption from the vapor state because of the influence of solvent and other solutes dissolved in the solvent.

True.

True or false. Vapor adsorption is the simplest adsorption model.

True.

True or false. Adsorption of polymers is often nearly irreversible.

True. Even with repeated washing.

The more polar the solute the _____ the adsorption that occurs from water.

less

Adsorption is an attempt by the system to _____ _____ _____ energy at the solid or liquid interface.

reduce the free

The more chemically ____ the solute and solvent and the more _____ the solid surface and solute, the greater the extent of adsorption.

unalike; alike