Quiz 3 pharmacy practice lab

Surfactants

can solubilize drugs by either a direct co-solvent effect it by uptake into micelles

Cremophor

is a nonionic surfactant molecule contain both a hydrophobic portion(tail) and hydrophilic portion(head) and can solubilize poorly water soluble drugs

Micelle formation*

when the surfactant molecules are dissolved in water at concentrations above the critical micelle concentration they form aggregates known as micelles

Heating Techniques

use to increase in the rate of solubilization and does not affect the intrinsic solubility of the substance , used when preparing highly concentrated solutions

Micelle formation

Heat stable oily ingredients (hydrophobic APIs, antioxidant, surfactant) are mixed together using heat (~65°C). Amount of water is heated separately to ~65°C then water is mixed slowly under constant stirring till a clear homogeneous solution is obtained. Heat labile and water-soluble ingredients are dissolved separately in water at room temperature and added to the preparation before making up the volume with the vehicle.

Preparing solutions

The minimum amount of water required to make clear solution is calculated using solubility information. When there is sufficient water, each ingredient may be dissolved separately and then mixed together. Alternatively, the solids are dissolved in water in order of solubility, least soluble first than most soluble.

electrolytes and minerals

requires the same thorough review of physical, chemical and therapeutic properties as other drug formulations

common adverse effects observed in these formulations

are related to the high osmolarity (or osmolality) and/or local irritant effects.

Many drugs and excipients are

incompatible in the presence of electrolytes and minerals resulting in precipitation.

Electrolyte solutions containing

sodium, potassium salts of chloride and/or citrate are used to replenish the electrolyte loss resulting from dehydration and use of certain diuretics

Highly hypertonic oral preparations must be

dissolved or diluted with the appropriate amount of water before administration to avoid gastrointestinal effects.

Hypertonic parenteral solutions must be

diluted appropriately with IV fluids or should be administered through large veins (such as the superior vena cava) to avoid local tissue irritation and other adverse effects

Incompatibilities, such as precipitation and degradation,

may occur when highly concentrated electrolyte solutions are mixed with certain drugs.

Osmotic Pressure

presure exerted by the molecules and ions present in the solution on the semipermeable membrane.

Non-electrolytes do not dissociate

so the number of particles exerting the osmotic pressure is directly related to the number of moles

Electrolytes dissociate into ions, and the

osmotic pressure depends on the ionic concentration.

The ionic concentration is calculated using the

percentage dissociation and the molar concentration of the solutions. Insoluble ingredients (suspended) do not exert osmotic pressure.

Osmolarity

is the concentration of the osmotically active particles (molecules, ions) per unit VOLUME (L)of solution

Osmolality

is the concentration of the osmotically active particles (molecules, ions) per unit MASS (kg) of solvent.

Tonicity

is the measure of the osmotic pressure gradient between two solutions separated by a semipermeable membrane.

A solution is isotonic when

its osmolality is similar to that of blood plasma.

A solution is hypertonic when its osmolality

is higher than that of blood plasma.

Equivalents

an element is the number of moles of the element that combine with 1 mole (1 g) of hydrogen.