Chemical Principles for Pharmacy Technicians

Atomic Structure and Bonding

  • Understand periodic table principles and the atomic structure of elements.

  • Distinguish between inter and intra molecular forces of attraction.

  • Describe chemical bonding occurring between atoms and between molecules.

Bases and Salts in Pharmacy

  • Basic drugs dissociate at high pH environments like the small intestine.

  • Examples of basic drugs: Morphine, Bupivacaine, and Levothyroxine.

  • Salts are compounds formed when an H+H^+ ion from an acid is replaced by a metal or another positive ion.

  • General reaction: Base + Acid →\rightarrow Salt + Water.

  • Example chemical reaction: HCl+MgO→MgCl2+H2OHCl + MgO \rightarrow MgCl_2 + H_2O.

pH Buffers

  • Solutions that resist pH changes when small amounts of acid or base are added.

  • Can be formulated to a specific pH; acidic buffers maintain a pH < 7.

  • Composition: Consists of either a weak acid and its conjugate base or a weak base and its conjugate acid.

Chemical Formulae and Isomers

  • Molecular formulae: Indicates the total number of each element in a molecule.

  • Displayed formulae: Visualizes all atoms and bonds (represented as lines).

  • Structural formulae: Shows the arrangement of atoms without displaying every bond.

  • Isomers: Compounds possessing the same molecular formula but different structural formulae.

  • Stereoisomers: Occur because double bonds are unable to rotate freely.

Solubility and Concentration

  • Solvent: The liquid in which a substance is dissolved.

  • Solute: The substance being dissolved.

  • Saturated solution: Contains the maximum amount of solute dissolvable at a specific temperature.

  • Supersaturated solution: Contains more than the maximum amount of solute; unstable and likely to crystallise.

  • Isotonicity: Describes two solutions that share the same concentration.

Factors Affecting Solubility

  • Temperature: As temperature increases, solubility increases for solids/liquids but decreases for gases.

  • Polarity: Solutes typically dissolve in solvents with similar polarity.

  • Pressure: The solubility of gas is directly proportional to pressure; solids and liquids are unaffected.

  • Molecular size: Larger particles generally exhibit lower solubility.

  • Stirring: Enhances the speed of the process but does not change the total solubility of a substance.

Suspensions

  • A mixture where solute particles remain undissolved and are larger than those in solutions.

  • Physical characteristics: Suspensions appear cloudy or murky, while solutions are usually transparent.

  • Pharmaceutical definition: Liquid dosage forms containing finely divided insoluble materials in a suspending medium.

  • Pharmaceutical examples: Antacid oral suspensions, Antifungal oral suspensions, and Analgesic oral suspensions.