Saturated Solutions and Solubility

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Which statement best describes a saturated solution?

A solution with no undissolved solute present.
A solution in which there is a dynamic equilibrium between dissolved and undissolved solute at a given temperature. (correct)
A solution containing solute at a concentration below the saturation point at a given temperature.
A solution where the solute concentration exceeds the saturation point at a given temperature.

Solubility, in quantitative terms, refers to the rate at which a solute dissolves in a solvent.

False (B)

Briefly explain the significance of maintaining a constant temperature during the solubility determination process.

Temperature affects solubility

The spontaneous interaction of two or more substances to form a homogenous dispersion is known as ______ or dissolution process.

solvation Signup and view all the answers

Match each solution type with its correct definition:

Saturated Solution = Contains the maximum amount of solute that can dissolve at a given temperature. Unsaturated Solution = Contains less solute than the maximum amount that can dissolve at a given temperature. Supersaturated Solution = Contains more solute than the maximum amount that can dissolve at a given temperature; unstable. Signup and view all the answers

Which of the following is NOT a reason why understanding solubility is important for a pharmacist?

Predicting patient compliance based on taste. (B) Signup and view all the answers

A true solution is a heterogeneous dispersion of solute and solvent.

False (B) Signup and view all the answers

What is the role of the solvent in a true solution?

dispersion medium Signup and view all the answers

The process by which a drug becomes available to reach sites of absorption and interact with therapeutic targets is known as ______.

distribution Signup and view all the answers

Which of the terms refers to the substance that is dispersed or dissolved in a solution?

Solute (D) Signup and view all the answers

What is one of the primary reasons for pharmacists to study solubility?

To select the best solvent(s) for a drug or mixture of drugs. (C) Signup and view all the answers

Understanding drug solubility is irrelevant to predicting its ADME (Absorption, Distribution, Metabolism, Excretion) properties.

False (B) Signup and view all the answers

Match the following terms with their descriptions:

Solute = Dispersed substance in a solution Solvent = Dispersion medium of a solution True Solution = Homogenous mixture of two or more components Distribution = Process of drug reaching sites of absorption Signup and view all the answers

Based on the graph, which compound's solubility is most affected by changes in pH?

Oxytetracycline (amphoteric) (A) Signup and view all the answers

Salt formation is a strategy used to decrease the solubility of a drug.

False (B) Signup and view all the answers

Based on the solvent polarity scale, which solvent would be most effective at dissolving organic salts?

Water (B) Signup and view all the answers

Name two chemical properties of solutes that can be inferred from their chemical structure and that may affect solubility.

Ionizable groups or polar groups or lipophilic groups Signup and view all the answers

The crystal structure of a solute can be either __________ or crystalline.

amorphous Signup and view all the answers

Non-polar solvents are effective at reducing the attraction between ions of strong electrolytes.

False (B) Signup and view all the answers

What type of intermolecular forces enables non-polar solvents to dissolve non-polar solutes?

van der Waals forces Signup and view all the answers

Why is it important to consider the different crystal forms (polymorphs) of a drug?

Different forms may have different solubility and stability. (B) Signup and view all the answers

Ester formation is used to decrease solubility.

False (B) Signup and view all the answers

According to the reading, solubility generally ______ with an increase in temperature.

increases Signup and view all the answers

Match the solvent with the type of solute it is most likely to dissolve:

Water = Inorganic salts Ethyl alcohol = Waxes Hexane = Fixed oils Signup and view all the answers

Match each pH range with the most suitable description of Indomethacin's solubility changes, based on the figure:

pH 2-4 = Solubility is low and relatively constant pH 6-8 = Solubility slightly increases pH 10-12 = Solubility significantly increases Signup and view all the answers

Which factor related to the chemical structure of a drug is LEAST likely to be relevant when predicting its solubility?

The color of the compound (B) Signup and view all the answers

Which structural feature of a solute would most enhance its solubility in polar solvents?

The presence of multiple polar groups (A) Signup and view all the answers

Mineral oil is a polar solvent.

False (B) Signup and view all the answers

List three factors influencing the solubility of solid/liquid systems.

Temperature, Solvent, pH Signup and view all the answers

Which of the following is NOT a type of solution of pharmaceutical importance mentioned?

Gas/gas solutions (C) Signup and view all the answers

The ability of two liquids to mix in all proportions, forming a homogenous solution, is known as ______.

miscibility Signup and view all the answers

Polymorphism in drug crystals affects which of the following physical properties most directly due to differences in bond energy?

Melting point (A) Signup and view all the answers

Complexation of a drug using complexing agents generally leads to a decrease in the drug's water solubility.

False (B) Signup and view all the answers

Define the term 'partition coefficient' and explain what it measures.

The partition coefficient is the ratio of a drug's concentration in two immiscible solvents at equilibrium, typically octanol and water. It measures the drug's relative solubility in these solvents, indicating its lipophilicity or hydrophilicity. Signup and view all the answers

The use of __________ with many drugs can form inclusion complexes that have a higher water solubility.

cyclodextrine Signup and view all the answers

Match the technique with its application in drug characterization:

Kp = Physicochemical measurement of drug permeability X-ray diffraction = Analysis of crystal structure in polymorphism Distribution coefficient (K) = Quantifies drug partitioning between two immiscible liquids Signup and view all the answers

Which of the techniques is NOT a method for measuring drug permeability?

Spectroscopic (A) Signup and view all the answers

A high partition coefficient (K) generally indicates that a drug is more soluble in water than in octanol.

False (B) Signup and view all the answers

Explain how temperature can affect the partition coefficient of a drug.

Temperature can influence the solubility of a drug in each phase, altering the equilibrium concentrations and therefore changing the partition coefficient. Higher temperatures may increase solubility in one or both phases, shifting the distribution. Signup and view all the answers

The distribution coefficient, K, is calculated by the concentration in solvent 1 (C1) divided by the __________ in solvent 2 (C2).

concentration Signup and view all the answers

What is the primary reason for using complexation in drug formulation?

To increase drug water solubility (D) Signup and view all the answers

Which of the following is NOT a parameter used in the Biopharmaceutical Classification System (BSC)?

Particle Size (C) Signup and view all the answers

A drug with high permeability and low solubility is classified as a Class I drug according to the Biopharmaceutical Classification System.

False (B) Signup and view all the answers

According to the BSC, a drug is considered highly soluble when its highest dose strength is soluble in how much aqueous media (in mL)?

250 Signup and view all the answers

For an immediate release product to be considered rapidly dissolving, no less than _____% of the labeled amount of the drug substance must dissolve within 15 minutes.

85 Signup and view all the answers

A drug is determined to be highly permeable when the extent of absorption in humans is what percentage, or greater, of the administered dose?

90% (C) Signup and view all the answers

Match the BSC Class with its primary characteristic related to oral bioavailability:

Class I = Ideal for oral administration, no expected bioavailability issues Class II = Dissolution is the rate-limiting step for bioavailability Class III = Rapid release from the dosage form is critical due to low permeability Class IV = Poor oral bioavailability, often requiring alternative routes of administration Signup and view all the answers

Which BSC class is likely to benefit most from formulation approaches that enhance drug dissolution?

Class II (B) Signup and view all the answers

The Biopharmaceutical Classification System (BSC) can be used to guide chemical modifications during lead optimization to improve a drug's physicochemical properties.

True (A) Signup and view all the answers

Which of the following drugs is classified as a Class IV drug, indicating poor oral bioavailability?

Furosemide (B) Signup and view all the answers

For a drug to be considered 'highly soluble' under BSC guidelines, at what pH range must it exhibit the required solubility in aqueous media?

pH 1 to 7.5 (D) Signup and view all the answers

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Solubility

The maximum amount of a substance that can dissolve in a given amount of solvent at a specific temperature.

Importance of Solubility

Helps in selecting the best solvent for a drug, overcoming formulation problems, and understanding drug action.

Solubility's Role in ADME

Determines if a drug can reach absorption sites, interact with targets, and undergo metabolism/excretion.