Introduction

• What is the definition of a pharmaceutical?

  A drug or medicine prepared or dispensed in pharmacies for medical treatment
• What is a pharmaceutical aid?

  Substances used to assist or enhance the action of drugs in treating illnesses
• What are some examples of pharmaceutical aids?

  Excipients, preservatives, buffers, and other additives
• What is the purpose of compounding in pharmaceuticals?

  To create a medication tailored to the needs of an individual patient
• What is a suspension in pharmaceutical terms?

  A type of preparation where fine particles of a solid are dispersed within a liquid
• What acid is commonly found in lemon juice?

  Citric acid
• Why is citric acid classified as a weak organic acid?

  Because it partially dissociates in solution
• What is the main component of baking soda?

  Sodium bicarbonate
• What is the role of buffers in a solution?

  To maintain the pH of a solution within a narrow range
• Why are buffers important in pharmaceutical preparations?

  They ensure stability and effectiveness of drugs sensitive to pH changes
• What is an example of a buffer mentioned in the material?

  Citric acid/sodium citrate buffer
• What do antioxidants do?

  They inhibit oxidation
• Why are antioxidants important in pharmaceuticals?

  They prevent degradation of active ingredients
• Where are antioxidants commonly found?

  In colored fruits and vegetables
• What are amphoteric substances?

  Can act as an acid or base
• To which type of solutions does Arrhenius's Theory apply?

  Aqueous (water-based) solutions only
• Strong Acids: pH < 3 (typically between 1–3).

  Slightly Acidic: pH between 4 and 6.

  Strong Bases: pH > 11 (typically between 11–14).

  Slightly Basic: pH between 8 and 10.
• Methods for Approximation of pH

  • Litmus Paper: Provides a rough estimation of pH by changing color in acidic (red) or basic (blue) solutions.
  • pH Paper: Measures a broader range of pH levels with color variations.
  • pH Meter: Measures the exact pH of a solution electronically, giving a precise reading.
• • Hydrogen Ion Concentration:
  • [H⁺] > 10⁻⁷: Acidic solution.
  • [H⁺] < 10⁻⁷: Basic solution.
  • Acidity, Alkalinity, and Neutrality: Determined by pH value (7 is neutral, <7 is acidic, >7 is basic).
• • Containers may react with certain pharmaceutical solutions, potentially creating new compounds that could alter the pH or stability of the solution. This can lead to reduced efficacy or potential safety issues with medications.
• Antimicrobials are often acidic, as acidic environments can inhibit microbial growth.
• Therapeutic Applications:

  • GI Tract and Body Fluid pH Control: Acids and bases are used to adjust the pH levels in the gastrointestinal (GI) tract, body fluids, and urine.
  • Example:
  • Dilute HCl: Used to treat achlorhydria (a lack of gastric acid secretion) by restoring an acidic environment in the stomach.
  • Sodium Bicarbonate: Acts as an antacid to neutralize excess gastric acid and can treat metabolic acidosis.
• Buffer Systems:

  • Acid-base conjugate pairs function as buffers in the body and pharmaceutical solutions.
  • Function: Buffers help maintain a stable pH by donating (acid) or accepting (base) protons as needed.
• Analytical Applications:

  • Acid-Base Titrations: Acids and bases are used in analytical procedures like acidimetry and alkalimetry to determine the concentration of a substance.
  • Example: Sodium hydroxide (NaOH) can be assayed by titration with hydrochloric acid (HCl) or sulfuric acid (H₂SO₄).
• pH Adjustment in Preparations:

  • Used as acidifiers or alkalizers in various pharmaceutical preparations and tests to achieve specific pH conditions.
  • Examples:
  • Ammonia Solution: Used to create an alkaline pH in the limit test for iron.
  • Sulfuric Acid (H₂SO₄): Provides an acidic environment in assays involving potassium permanganate (KMnO₄), where it helps reduce permanganate ions (Mn⁷⁺) to manganous ions (Mn²⁺), releasing oxygen in the process.
• Neutralization Reactions:

  • Acid-base neutralization reactions are employed to convert drugs into various salt forms (e.g., hydrochloride, sulfate, sodium salts), making them more stable or suitable for formulation in pharmaceutical products
• Arrhenius Acid-Base Theory

  Acid: Yields H⁺ ions in water; e.g. HCl → H⁺ + Cl⁻

  Base: Yields OH⁻ ions in water; e.g. NaOH → Na⁺ + OH⁻
• Lewis Acid-Base Theory

  Acid: Electron pair acceptors; BF₃ (boron trifluoride), accepts electron pair from NH₃

  Base: Electron pair donors
• Bronsted-Lewis

  Acid: Proton (H⁺) donors; H₂SO₄ (sulfuric acid)

  Base: Proton (H⁺) acceptors; NH₃ (ammonia), accepts H⁺
• Bronsted-Lowry (Conjugate Pairs)

  Acids: Forms conjugate base upon donating H⁺

  Base: Forms conjugate acid upon accepting H⁺

  Example: HCl + H₂O ↔ H₃O⁺ + Cl⁻ (HCl is an acid, Cl⁻ is its conjugate base)