M2 Chapter 10

Question 1

What are Pharmaceutical solutions?

Answer 1

A liquid preparation that contain one or more chemical substances dissolved in a suitable solvent or mixture of mutually miscible solvents.

(USP definition)

Question 2

What are syrups?

Answer 2

Solutions containing high concentration of sucrose or other sugars

Question 3

What are elixirs?

Answer 3

A clear, pleasantly flavored, sweetened hydro-alcoholic liquid containing API for oral use.

Question 4

What are spirits?

Answer 4

An alcholic or hydro-alcoholic solution of volatile substance.

Question 5

What are Tinctures?

Answer 5

An alcoholic or hydro-alcoholic solution from plants or chemcials

Question 6

What are some extracts?

Answer 6

A concentrated preparation of natural products by extraction

Question 7

There are also some lotions, sprays, medicated oils and others.

Answer 7

These are about of pharmaceutical solutions

Question 8

How are pharmaceutical solutions classified?

Answer 8

Route of administration

• Oral, topical, otic, ophthalmic, parenteral and others

Question 9

How do you describe solubility quantitatively and qualitatively?

Answer 9

Quantitative is by the concentration of drug (API)

Qualitative is in terms of approximate solubility

Question 10

Define Solubility

Answer 10

Solubility is defined in quantitative terms as the concentration of a solute in a saturated solution, at a certain temperature and pressure.

S (solubility) indicates the saturated solution concentration (mol/L)

Question 11

What is a saturated solution?

Answer 11

A saturated solution of a solid material is in equilibrium between the solute phase and the solid phase.

Question 12

What is a supersaturated solution?

Answer 12

A supersaturated solution is possible; some substances are dissolved in a higher concentration than it could normally obtain at equilibrium.

Question 13

What are the solubility definitions as well as the ranges?

Answer 13

• Very Soluble (VS)
• Freely Soluble (FS)
• Soluble
• Sparingly soluble (SPS)
• Slightly soluble (SS)
• Very slightly soluble (VSS)
• Practically insoluble (PI)

Question 14

What are the three steps a substance must undergo to dissolve?

Give the Equation that is involved.

Answer 14

1. Solvent and solute are segregated, each interacts primarily with other molecules of the same type.
2. To move a solute molecule into solution, the interactions among solute molecules in the crystal (lattice energy) and among solvent moelcules in the space required to accommodate the solute (cavitation energy) must be broken.
3. Once the oslute molecule is surrounded by solvent, new stabilizing interactions between the solute and solvent are formed (solvation energy).

S + S = e ^ (- delta G release - delta G cavity + delta G solvation) / RT

Question 15

What are the different intermolecular forces?

Answer 15

• Hydrogen Bond
• Ionic interactions
• Van der Waals

Question 16

What are the mechanisms involved in Polar Solvents?

Answer 16

• Polarity of a molecule (molecular dipole moment, ration of polar and nonpolar groups)
• Hydrogen-bond formation: Strong
• Ionization of water

Question 17

What is involved in semi-polar solvents?

Answer 17

• They are often used as _intermediate solvent_s (aka co-solvents)
• Can induce some degree of polarity in nonpolar molecule
• e.g. acetone, glycerin, propylene glycol used as co-solvents to increase the solubility of organic molecules.

The functional groups that surround semi-polar solvents are Alcohol, aldehyde, ketone, and amine.

Question 18

What is a Dipole?

Answer 18

A separation of two opposing charges q over a distance r

Question 19

What is a dipole moment?

Answer 19

u = qr

(a measure of molecular polarity)

q = charge difference between polar and non-polar

r = relates to the shape

Question 20

Desribe Dielectric Constant

Answer 20

Capacitance: C=q/V

Dielectric constant: Cx/Co

The bigger the dielectric constant the more polar it is.

(Increase Dielectric Constant, Increase Polarity)

Question 21

When you have a mixture of liquid and liquid what is the miscibility between two liquids described as?

Answer 21

• Complete miscible: refers to a liquid solute that will form a solution with a liquid solvent over any concentration range. e.g. water-alcohol, glycerin-alcohol, benzene-tetrachloride
• Partial Miscibility: when liquids are not completely miscible, their solubility (miscibility) needs to be disscuess. e.g. binary system of phenol and water

Question 22

Phase diagrams are a two component system (binary)

What are phase diagrams and give an example as well as a critical solution temperature.

Understand the diagram

Answer 22

• Phase diagrams are used to show the equilibrium conditions between multiple phases
• Example: A temperature-composition diagram to describe the influence of temperatrue miscibility at different compositions.
• The critical solution temperature 66.8 degress Celcius on the right.

Question 23

What are involved in phase diagrams of three-component systems?

Answer 23

Ternary System

Triangular corrdinate graphs is useed to describe the equilibrium conditions between 3 phases.

Question 24

What are the type of things that influence the solubility of a solid?

Answer 24

1. Influence of pH: calculating the solubility of weak electrolytes
2. Influence of solvents
3. Influence of surfactants
4. Influence of complexation
5. Influence of other factors

Question 25

What is the calculation of pH and Solubility of weak acid?

Answer 25

In a saturated solution:

• So - [HA]_sat
• Molar solubility of unionized weak acid at any pH
• S = [HA] + [A-]
  
  • Total apparent solubility of any form of the weak acid
• Neglect any further secondary dissociation

pH = pKa + log [(S-So)/So]

Question 26

What are the pathways available for drug absorption?

Answer 26

1. Transcellular pathway (throught the epithelial cells, intracellular)
2. Paracellular pathway (in between adjacent cells, intercellular)
3. Receptor-mediated endocytosis
4. Absorption into the lymphatic ciruclation

Question 27

What is Extraction?

Answer 27

Extraction is a basic and useful technique for:

• Drug extraction, isolation and purifecation from: Natural product, and from chemical synthesis or biosynthesis
• Bio-analysis: measure drug concentration in blood and measure pollution from environmental sample.

Question 28

What are the Classification of Complexes?

Answer 28

• Inorganic Complex: metal-ion complexes and Chelates
• Organic molecular complexes
• Physical Inclusion/occlusion complexes: Monomoecular type: inclusion molecule
• Biochemical MAcromolecular complex: Protein drug binding
• Nanotechnology

Question 29

Describe Inorganic metal complex: Coordinate Covalence?

Answer 29

Metal ions as electrons acceptors: coordination through hybridization.

Ligands as electron donors: H2O, NH3, CH-, Cl-

Question 30

What is the chelating agent EDTA?

Answer 30

EDTA (ethylene-diamine-tetra-acetic-acid): sequester iron and copper ions so that they cannot catalyze the oxidative degradation.