Table of Contents
What are Antimicrobial Agents?
Antimicrobial agents are substances that prevent the growth of microorganisms — bacteria, fungi, viruses, and parasites. They are used in pharmaceutical and hospital settings as cleaners and dressings to maintain sterile areas. In medicine, they prevent and treat infections in humans and animals, functioning as both antiseptics (applied to living tissue) and disinfectants (applied to non-living surfaces).
Classification
| Type | Action |
|---|---|
| Antibiotic agents | Work against bacterial infections |
| Antifungal agents | Work against fungal infections |
| Antiviral agents | Work against viral infections |
| Antiparasitic agents | Work against parasitic infections |
Silver Nitrate
Formula: AgNO₃ | Molar Mass: 169.87 g/mol
Preparation: 3Ag + 4HNO₃ → 3AgNO₃ + 2H₂O + NO
Mechanism: The ionic bond breaks and releases free silver ions, which bind to tissue proteins of microbes and destroy cellular activity.
| Property | Description |
|---|---|
| Color & State | Colourless crystalline powder or solid |
| Odour & Taste | Odourless; bitter metallic taste |
| Solubility | Soluble in water and glycerol |
- Preparation: Cream, gel, solution.
- Brand names: Silverex, Burn Heal, Sivacure+
- Storage: Well-closed, airtight container; away from copper, heat, light, and moisture — very sensitive to heat and decomposes into ionic form
Uses:
- Antibacterial and antiseptic — precipitates microbial surface proteins
- Widely used as a burn cream and wound cleaning agent
- Used in sanitiser and cleaner preparations
- Helps create a scab to stop bleeding from minor skin wounds
Ionic Silver
Formula: Ag⁺ | Molar Mass: 107.868 g/mol
Free silver ions bind to surface proteins of microbes forming complexes or precipitates. Very dilute solutions act as astringent and mild antiseptic.
Ag⁺ + Cl⁻ → AgCl(s)
| Property | Description |
|---|---|
| Color & State | Clear colourless liquid |
| Odour & Taste | Odourless; metallic taste |
| Solubility | Insoluble in water under normal conditions |
- Preparation: Cream, gel, solution.
- Brand names: Sulfhex, Sildaflo, AgNeon, Silvebel.
- Storage: Well-closed, airtight container; away from copper, heat, and moisture
Uses:
- Manufacturing antiseptic creams, solutions, and liquids
- Topical treatment of burns and chronic wounds
- Used as a coating for medical devices
- Used in toothpaste manufacturing
Chlorhexidine Gluconate
- Formula: C₃₄H₅₄Cl₂N₁₀O₁₄ | Molar Mass: 897.75 g/mol
- Also known as: Chlorhexidine digluconate
Mechanism: Positively charged — reacts with negatively charged microbial cell surfaces, destroying cell membrane integrity.
| Property | Description |
|---|---|
| Color & State | Colourless or pale yellow powder or solution |
| Odour & Taste | Odourless; bitter taste |
| Solubility | Practically insoluble in water; salts easily soluble |
- Preparation: Mouthwashes, gel, lozenges, solution, gauzes.
- Brand names: Hexidine, Hexigel, Septlon, Cuticell, Bactigras.
- Storage: Amber-coloured, well-closed container; away from light and moisture
Uses:
- Skin disinfection before surgery; sterilisation of surgical instruments
- Widely used in dental preparations — treats dental caries and prevents plaque
- Wound cleaning and healing agent
- Treats yeast infections of the mouth
Hydrogen Peroxide
Formula: H₂O₂ | Molar Mass: 34.02 g/mol
Preparation: BaO₂·8H₂O + H₂SO₄ → BaSO₄ + H₂O₂ + 8H₂O
| Property | Description |
|---|---|
| Color & State | Almost colourless or pale yellow liquid |
| Odour & Taste | Odourless; bitter taste |
| Solubility | Soluble in water in all proportions |
- Preparation: Solution, cream.
- Brand names: Peroxida, Crystacide, Hydrogen Peroxide Solution.
- Storage: Amber-coloured, well-closed container; away from light and moisture
Uses:
- Primary use — washing and cleaning wounds
- Mild antiseptic to prevent infection of minor cuts, scrapes, and burns
- Used in ear wax softening and removal
Boric Acid
Formula: H₃BO₃ | Molar Mass: 61.83 g/mol
A weak monobasic acid that acts as a Lewis acid by accepting electrons from a hydroxyl ion. On heating above 370K forms metaboric acid (HBO₂), which further yields boric oxide (B₂O₃).
H₃BO₃ → HBO₂ → B₂O₃
| Property | Description |
|---|---|
| Color & State | White crystalline powder with soapy touch |
| Odour & Taste | Foul odour; slightly acidic taste |
| Solubility | Sparingly soluble in water; highly soluble in hot water |
- Preparation: Powder, ointment, drops, suppositories.
- Brand names: Boricada, Borexa, Boricap, Boric Acid Powder.
- Storage: Well-closed, airtight container; away from light and moisture
Uses:
- Antiseptic washing to control infection
- Used during eye infection, irritation, and inflammation
- Boric acid suppositories prevent vaginal infections and maintain vaginal pH
- Used in skin diseases — rashes, irritation, dermatitis
Bleaching Powder
- Formula: CaOCl₂ | Molar Mass: 142.98 g/mol
- Also known as: Calcium oxychloride, Chlorinated lime
Preparation: Ca(OH)₂ + Cl₂ → CaOCl₂ + H₂O
| Property | Description |
|---|---|
| Color & State | Yellowish-white crystalline powder |
| Odour & Taste | Chlorine-like odour and taste |
| Solubility | Soluble in polar solvents (water); insoluble in non-polar solvents (ether) |
- Preparation: Powder, solution.
- Brand names: Aquafit, HTH Granules.
- Storage: Well-closed, airtight container; away from light and moisture
Uses:
- Disinfectant and germicide — especially for sterilisation of drinking water
- Sterilising hospital equipment and laboratory platforms
- Primary chlorine source in pharmaceutical and chemical industries
Potassium Permanganate
Formula: KMnO₄ | Molar Mass: 158.03 g/mol
Preparation: 2K₂MnO₄ + 4HCl → 2KMnO₄ + MnO₂ + H₂O + 4KCl
| Property | Description |
|---|---|
| Color & State | Dark purple crystal solids |
| Odour & Taste | Odourless; sweet taste |
| Solubility | Water soluble; more soluble in hot water |
- Preparation: Solution, powder.
- Brand names: Potassium Permanganate Crystals.
- Storage: Well-closed, airtight container; away from flammables, combustibles, reducing agents, light, and moisture
Uses:
- Treatment of foot infections, superficial wounds, dermatitis, and topical ulcers
- Mild antiseptic with astringent properties for weeping skin conditions
- Removal of hydrogen sulphide and iron from well water
D.Pharma 1st Year — All Subjects Notes
D.Pharma 2nd Year — All Subjects Notes