Pharmaceutical Preparations and Drug Delivery Systems

Posted on May 5, 2024 in Biology

Ophthalmic Preparations

Eye Drops

Ophthalmic preparations, commonly known as eye drops, are sterile solutions or suspensions used for eye treatment. They can be administered as drops, sprays, or ointments.

Types of Ophthalmic Preparations:

  • Eye drops
  • Eye ointments
  • Contact lens solutions

Factors Affecting Eye Drop Formulation:

  • Sterility
  • Pain and irritation
  • Antimicrobial activity
  • pH adjustment
  • Viscosity
  • Isotonicity with tears
  • Volume

How to Use Eye Drops:

  1. Wash your hands.
  2. Gently pull the lower eyelid down.
  3. Hold the dropper above the eye and place 1-2 drops inside.
  4. Release the lower lid and keep the eye open for at least 30 seconds.

Eye Ointments

Eye ointments are sterile preparations meant for application to the eye. They should possess the following characteristics:

  • Sterile (heat sterilized)
  • Free from irritants
  • Uniform drug diffusion
  • Melting point close to body temperature

Preparation Methods:

  • Trituration method: Used for drugs unstable at sterilization temperatures.
  • Fusion method: Used for drugs stable at sterilization temperatures.

Calibration and Validation

Calibration

Calibration is the process of measuring and adjusting an instrument’s accuracy to ensure it falls within the optimal working range.

Validation

Validation is the process of establishing documented evidence that a specific process consistently produces a product meeting predetermined specifications and quality attributes.

Types of Validation:

  1. Equipment Validation: Ensures equipment consistently produces products meeting specifications.
  2. Design Qualification: Verifies that the instrument meets customer requirements before dispatch.
  3. Installation Qualification: Ensures the instrument is installed according to specifications and facilities meet requirements.
  4. Operational Qualification: Confirms the equipment operates as per manufacturer specifications.
  5. Method Validation: Provides assurance that analytical methods consistently yield accurate and reproducible results.

Vaccines

Vaccines are preparations containing live attenuated (weakened) or killed microorganisms, or parts of them, that stimulate an immune response.

Advantages of Vaccines:

  • Safe for immunocompromised individuals and pregnant women.
  • Less expensive.
  • Lower storage requirements.

Disadvantages of Vaccines:

  • Sterile preparation can affect vaccine dose.
  • Antibodies may not recognize the same protein in different parts of the body.

Types of Vaccines:

  • Live Attenuated Vaccines (e.g., MMR)
  • Inactivated Vaccines (e.g., Hepatitis A)
  • Recombinant Subunit Vaccines (e.g., Hepatitis B)
  • Toxoid Vaccines (e.g., Diphtheria)

Vaccine Production Process:

  1. Antigen Generation: Growing and harvesting proteins or DNA of the pathogen.
  2. Antigen Release and Isolation: Separating antigens from cells and isolating proteins.
  3. Purification: Using membrane separation and chromatography to isolate inactivated antigens.
  4. Addition of Excipients: Formulating the vaccine with adjuvants to enhance immune response.
  5. Packaging: Sealing vials or syringes containing the vaccine with sterile stoppers.

Sera

Sera are blood components that are neither blood cells nor clotting factors but the liquid portion of blood (plasma). Sera contain electrolytes, antibodies, antigens, hormones, etc.

Factors Affecting Immunity

1) Phagocytosis

Phagocytosis is the process of engulfing and destroying bacteria by phagocytes, which include:

  • Cells of the reticuloendothelial system
  • White blood cells

2) Antibody Production

Antibodies are substances produced by the body in response to foreign proteins (antigens) for protection. Types of antibodies include:

  • Alpha antibodies
  • Beta antibodies
  • Gamma antibodies (most common)

Parenteral Preparations (Injections)

Parenterals are sterile, pyrogen-free preparations administered by injection into the skin, muscle, or veins.

Advantages of Parenterals:

  • Immediate physiological response
  • Prolonged action formulations
  • Suitable for unconscious patients
  • Useful for uncooperative or nauseous patients
  • 100% bioavailability

Disadvantages of Parenterals:

  • Requires trained personnel for administration
  • Painful administration
  • High production cost
  • Difficult to reverse effects once administered

Novel Drug Delivery Systems

Dendrimers

Dendrimers are highly branched, spherical polymers used as carriers for drug delivery due to their biocompatibility and unique properties.

Advantages of Novel Drug Delivery Systems:

  • Protection from degradation
  • Enhanced stability
  • Reduced toxicity
  • Increased bioavailability
  • Enhanced solubility
  • Controlled drug release
  • Enhanced pharmacological activity

Challenges in Novel Drug Delivery:

  • Bioavailability, especially for insoluble compounds
  • Targeted drug delivery to specific areas
  • Controlled drug release