Pharmaceutics 1 Final Exam

This set contains only the new material for the exam not exam 1 or exam 2 content

There are Solute transport ( facilitated, passive or active ) or Solvent transport (osmosis)

Describe the different forms of transport processes in biological and pharmaceutical systems.

Passive Transport: Movement of solute molecules across a membrane without energy input. High to low. Driven by concentration gradient.

Facilitated Transport: Movement of solute molecules across a membrane with the help of transport proteins. High to low

Active Transport: Movement of solute molecules against their concentration gradient, requiring energy input. Low to high

Distinguish between passive, facilitated, and active transport of solute molecules.

Amino acid transporter= methyldopa, gabapentin, baclofen, cycloserine

Oligopeptide transporter = cephalexin, cefadroxil, cefixime, lisinopril

Phosphate transporter = foscarnet, fostomycin

Provide examples of drug molecules transported via different mechanisms

Thermodynamics: Determines if a process is energetically favorable or not.

Kinetics: Considers the rate at which a process occurs.

Thermodynamics ensures that molecules move from high to low concentration (favorable gradient).

Kinetics determines the speed at which molecules cross the region (affected by factors like temperature and molecular size).

Overall, thermodynamics governs the direction, while kinetics influences the speed of molecule transport.

Explain the role of thermodynamics and kinetics in the transport of molecules across a region.

Osmosis is the movement of solvent molecules from an area of lower solute concentration to an area of higher solute concentration through a semipermeable membrane. It plays a crucial role in pharmaceutical processes by aiding in drug dissolution, drug delivery, and maintaining cell hydration and function.

Define the process of osmosis and explain its role in pharmaceutical processes.

Cd = Concentration of solute at the donor side

C1 = Concentration of solute (solubility) in the membrane at donor side

C2 = Concentration of solute (solubility) in the membrane at the receptor side

Cr = Concentration of solute at the receptor side

h = Thickness of the membrane (in cm)

D = diffusion coefficient (cm2/s)

K = partition coefficient                    

S= surface area

Identify the different terms and units of Fick's law of diffusion.

the concentration of a solute in a saturated solution at equilibrium (at a given temperature).

Units = concentration expression (mg/ml, g/L, mole/L)

Drugs must be in solution to be absorbed, transported, and to interact with active sites

To be effective, drugs need to have some degree of solubility in both aqueous and lipid systems (BCS) Class 2

Define and understand the terms and concepts of solubility

1. Soluble: Able to dissolve in a given solvent.

2. Very soluble: Highly capable of dissolving in a specific solvent.

3. Slightly soluble: Exhibiting limited ability to dissolve in a particular solvent.

4. Sparingly soluble: Dissolving to a small extent in a given solvent.

5. Insoluble: Not capable of dissolving appreciably in a specific solvent.

Identify the USP terms for solubility and their meaning

Molecular Structure

Molecular Weight

Crystal Structure

Stereochemistry

Ionization

Temperature

Recognize factors that affect solubility.

Like dissolves like – hydrophilic molecules (e.g., ethanol) dissolves well in water

Solubility in water increases with increasing capacity for hydrogen bonding (i.e., more OH, NH2, COOH groups, the higher the solubility)

Solubility in water decreases with increasing number of carbons (e.g., ethanol versus butanol)

Solutes with higher melting point will have lower aqueous solubility (e.g., wax)

Amorphous solutes are more soluble than crystalline

Explain the common solubility rules

Solubility refers to the maximum amount of solute that can dissolve in a solvent at a given temperature.

Dissolution is the process of a solute dissolving in a solvent to form a homogeneous mixture.

Solubility is a property, while dissolution is an action.

Distinguish between solubility and dissolution

The process by which a solid drug substance dissolves into a liquid, typically in the gastrointestinal tract. It is crucial for drug bioavailability as it determines the rate and extent of drug absorption into the bloodstream.

Describe the role of drug dissolution from dosage forms in drug bioavailability.

1. Surface area (A): The exposed area of drug particles.

2. Diffusion coefficient (D): Measure of how easily molecules move through a medium.

3. Concentration gradient (ΔC): Difference in drug concentration between the particle surface and the bulk solution.

4. Thickness of diffusion layer (h): Distance that drug molecules must travel to reach the particle surface.

5. Solubility (Cs): Maximum amount of drug that can dissolve in the solvent.

6. Temperature (T): Influences the rate of molecular movement and solubility. Remember: A, D, ΔC, h, Cs, T - all impact drug particle dissolution rate.

Relate the parameters of the Noyes-Whitney equation to the variables that affect the dissolution rate of drug particles.

1. Physicochemical: Solubility, particle size, temperature.

2. Formulation: Drug dosage form, excipients, pH.

3. Physiological: GI pH, gastric emptying rate, blood flow. Remember: Dissolution is affected by multiple factors, including properties of the drug, formulation, and physiological conditions.

Discuss how various physicochemical, formulation, and physiological factors can influence dissolution behavior.

Partitioning Law: Describes the distribution of a solute between two immiscible phases based on their respective concentrations.

Partition Coefficients (P / Log P): Measure the solute's distribution between two phases and are determined by the ratio of their concentrations.

Apparent Partition Coefficients: Account for the solute's interaction with other components in the system, affecting its distribution between phases.

Define the partitioning law, partition coefficients, and apparent partition coefficients.

High pH favors ionization, increasing water solubility and decreasing lipid solubility. Low pH promotes non-ionized form, enhancing lipid solubility and reducing water solubility.

Determine the effect of pH on the partition coefficient of weak electrolytes and on their excretion in different body fluids.

A dry substance composed of finely divided  particles

Define powder as a dosage form

Advantages

Increased stability compared to solutions

Easier to swallow than tablet or capsules (when used per se)

Faster dissolution due to large surface area

Rapid therapeutic effect

Possibly decreased GI irritation

Versatility (doses and dosage forms )

List advantages of powders as a dosage form

Bulk powders= Intended to be administered in dosage quantities that are safe for the patient to measure

Patient should be educated regarding the appropriate handling, storage, and solvent to be used (if needed)

Limited to nonpotent drugs

Should pass through a 100 mesh sieve

Examples: dusting powders, antacids, laxatives, dietary nutrient supplements, dentifrices

Divided powders = Also called “chartula”, “chart” or powder paper - a paper folded so as to form a packet for a powdered medicament

Single doses of the powdered drug mixture individually enclosed in paper, cellophane, or metallic foil wrappers or packets

Sufficiently potent to require premeasured doses

Examples: headache powders, laxatives

Compare and contrast bulk and divided powders

Methods used to combine multiple ingredients in powder preparation, such as trituration (grinding), levigation (grinding with a liquid), and geometric dilution (gradual blending of unequal quantities).

Explain and understand various compounding procedures applied in preparation of powders

Examples of medicated powders include talcum powder, which is used to soothe irritated skin and absorb moisture, and antifungal powders like miconazole powder, used to treat fungal infections like athlete's foot.

Provide examples of medicated powders used in prescription and nonprescription products.

Bitter or unpleasant taste  (oral powders)

Difficulty of protecting from decomposition (hygroscopic powders, and materials susceptible to oxidation)

Time and expenses required in the preparation of uniform powders are great

Patient may misunderstand the correct method of use

Bulky and inconvenient to carry

List disadvantages of powders as a dosage form

Hygroscopic: Absorbs moisture from the air. Example: potassium citrate.

Deliquescent: Absorbs moisture and dissolves in it. Example: Calcium chloride.

Efflorescent: Loses moisture to the air. Example: atropine sulfate.

Eutectic mixtures: A mixture with a lower melting point than its individual components. Example: aspirin.

Define and provide examples of hygroscopic, deliquescent, and efflorescent powders, and  eutectic mixtures

Dispense powders separately.

•Mix each compound with an equal amount of inert diluents (lactose, starch) and finally combine the diluted powders with light trituration

•Mix the materials together and allow them to liquefy, and then add sufficient amount of adsorbents to adsorb liquid

Adsorbing Agents: Kaolin, magnesium oxide and magnesium carbonate, talc, and silicic acid

Explain technological approaches for overcoming liquefaction of powders

Powders containing sodium bicarbonate, an organic (citric or tartaric) or inorganic (sodium biphosphate)  acid and medicinal agent to produce effervescence when mixed with water.

Heat method -  all the components are mixed with 15-20% of the acid ingredients (e.g., citric acid monohydrate) and heated on a bath at 100 oC. Granules are formed from the powder mass moistened with the water of crystallization released.

Wet method -  The citric acid is moistened and added to sodium bicarbonate. Granules are then formed from this partially fused mass.

Define and describe technology of effervescent salts

(Sifting top) containers

Divided Powders/Charts

Sachets/Pouches

Insufflators

List common type of powder packeging