
<ul>
  <li>Volume of distribution = dose/plasma concentration at time of administration</li>
  <li>
    With repeated administration, the plasma concentration is a function of the rate of
    administration and the rate of elimination
  </li>
  <ul>
    <li>Achieves steady state within 3-4 half-lives</li>
    <li>Steady state can be achieved faster by using a loading dose</li>
    <li>Drug half-life determines the frequency of subsequent doses</li>
  </ul>
  <li>
    Bioavailability: the amount of oral dose that reaches the systemic circulation and is available
    to the site of action
  </li>
  <ul>
    <li>May be limited by first-pass metabolism</li>
    <ul>
      <li>Gut motility</li>
      <li>Intestinal pH, bile salts</li>
      <li>Enterohepatic circulation</li>
      <li>Intestinal blood flow</li>
      <li>Intestinal microflora</li>
    </ul>
  </ul>
</ul>
<HotTopic>
  <p>
    Ocular topical drugs have higher bioavailability as they are absorbed via nasal mucosa and so
    avoid first-pass metabolism
  </p>
</HotTopic>
<ul>
  <li>Drug kinetics</li>
  <ul>
    <li>First-order: linear increase in rate with increased drug concentration</li>
    <li>Zero-order: saturation at high drug concentrations</li>
    <ul>
      <li>Eg. when the capacity of liver enzymes is consumed</li>
    </ul>
  </ul>
  <li>Drug penetration of cells</li>
  <ul>
    <li>Diffusing through lipid (depends on lipid solubility)</li>
    <li>Diffusion through aqueous pores</li>
    <li>Via carrier molecules</li>
    <li>Pinocytosis</li>
  </ul>
  <li>Drug distribution</li>
  <ul>
    <li>Binding affinity for plasma proteins eg. albumin</li>
    <ul>
      <li>Highly bound drugs tend to remain in the plasma</li>
    </ul>
    <li>Binding to tissue proteins</li>
    <li>Blood flow to different tissues</li>
  </ul>
</ul>
<HotTopic>
  <p>
    The blood-retinal and blood-aqueous barriers limit drug distribution in the eye. Usually only
    lipid-soluble drugs move between the blood and the retina. Systemically administered drugs do
    not necessarily produce high intraocular levels
  </p>
</HotTopic>
<ul>
  <li>Drug metabolism</li>
  <ul>
    <li>Occurs almost entirely in the liver</li>
    <li>Increases drug solubility for excretion</li>
    <li>Might activate a prodrug to its active form</li>
    <ul>
      <li>May inactivate others</li>
    </ul>
    <li>Phase I: oxidation</li>
    <ul>
      <li>Performed by cytochrome p450</li>
      <li>This group of enzymes also exists in the eye</li>
      <li>Numerous inducers and inhibitors (including chloramphenicol)</li>
    </ul>
    <li>Phase II: conjugation</li>
  </ul>
  <li>Drug excretion</li>
  <ul>
    <li>
      Renal excretion: varies widely between drugs depending on the kidneys capacity to handle the
      drug&rsquo;s properties
    </li>
    <ul>
      <li>Glomerular filtration (if not protein-bound and small enough ie. &lt;20,000Da)</li>
      <li>Tubular secretion into the glomerular filtrate</li>
      <li>Reabsorption</li>
    </ul>
    <li>Biliary excretion</li>
    <ul>
      <li>Conjugated drugs are concentrated in the bile and delivered to the intestine</li>
      <li>Drug may be released and re-absorbed (enterohepatic circulation)</li>
    </ul>
  </ul>
</ul>


Pharmacology

Pharmacokinetics

Intro

FRCOphth Part 1 Study Notes

Orbit and ocular adnexae

Orbit

Extraocular Muscles

Orbital Blood Vessels

Paranasal Sinuses

Lacrimal Glands

Tear Film

Eyelids

Blinking

Anterior segment - ocular surface

Conjunctiva

Conjunctivitis

Sclera

Cornea

Corneal Structure And Development

Corneal Physiology

AC to Lens

Angle

Ciliary Body

Aqueous Humour Dynamics

Iris

Pupil

Lens

Posterior segment

Choroid

Vitreous

Retinal Macrostructure

Neurosensory Retina

Retinal Pigment Epithelium

Neuroanatomy

Venous Sinuses

Cerebral Ventricles

Cerebral Blood Supply

Supranuclear Gaze Pathways

Head And Neck Autonomic Nervous Supply

Head And Neck Glands

Osteology

Nerves

Muscles And Pharyngeal Arches

Extraocular Nerves

Sensory Nerves

Physiology

Physics Of Blood Flow

Neuronal Control Of Blood Vessels

Oxygen-Haemoglobin Dissociation Curve

Cytochrome p450

Pituitary Gland

Thyroid Hormone Production

Insulin

Glucagon

Parathyroid Hormone

Corticosteroids

Catecholamines

Cardiac Cycle

Renal Physiology

Fluid Balance

Acid-Base Balance

Muscle Physiology

Sensory Fibres

Cutaneous Receptors

Endocytosis

Glycosaminoglycans

Condensed Ocular Biochemistry

Eye Movements

Accomodation

Vision

Visual Cycle And Phototransuction

Visual Pathway

Visual Acuity

Colour Vision

Binocular Vision

Pathology

Collagen

Tissue Damage

Inflammation

Disease Entities

Wound Healing

Thrombosis / Atherosclerosis

Cell Growth

Neoplasia

Histopathology

Nystagmus

Free Radicals And Antioxidants

Immunology

Ocular Immunology

Microbiology

Viral Infections

Bacterial Infections

Fungal Infections

Protozoa

Nematodes

Antimicrobials

Genetics

Chromosomes

Mitosis

Meiosis

Genes

Polypeptide Synthesis

Histones

MicroRNA

Hardy-Weinberg Equilibrium

Mutations

Chromosome Defects

Autosomal Inheritance

X-Linked Inheritance

Mitochondrial Inheritance

Multifactorial Inheritance