B.P CHAP 1

• Biopharmaceutics


  The study of relationship between the (nature) and (intensity) of biological effects observed in animal & man and various factors
• Factors influencing biological effects

  • Simple chemical modification of drugs such as formation of esters, salts and complexes
  • Modification of the physical state, particle size of the drug available to absorption site
  • Presence or absence of adjuvant in dosage form with the drug
  • The type of dosage form in which the drug is administered
  • Pharmaceutical process or process by which the dosage form is manufactured
• If made from compression & force is high the tablet friability can be effected
• Biopharmaceutics (B.P)


  The study of relationship between physio chemical properties of a drug in a dosage form and the various effects observed after the administration of the dosage form
• The study of B.P includes all possible effect of the dosage form on the biological response and all possible physiological factors which may affect the drug contained in the dosage form of the drug itself
• Bioavailability (B.A)


  The rate & extent to which active drug ingredient or therapeutic moiety (nucleus) is absorbed from drug product & becomes available at the site of action
• Aspects studied in B.A

  • The amount or proportion of drug absorbed from a formulation (product dosage form)
  • The rate at which the drug is being absorbed
  • The duration of drug presence in the biological systems
  • The relationship between the drug blood levels & clinical efficacy and toxicity
• During the production development stages proposed drug product pharmaceutical manufacturers use B.A studies to compare different formulations of drug substance to determine which one allows the most desirable absorption pattern
• Later B.A studies may be used to compare the availability of the drug substance in different production batches or to compare the availability of the drug substance in different dosage forms or in the same dosage form by different manufacturers
• FDA Bioavailability Submission Requirements

  • New Drug Application (NDA)
  • Abbreviated New Drug Application (ANDA)
  • Supplemental Application
• Conditions under which FDA may waive the In Vivo B.A Requirements

  • The product is a solution intended solely for IV administration and contain the same active agent in the same concentration & solvent as a product previously approved
  • The drug product is administered by inhalation as Gas/Vapour and contains the same active ingredient in the dosage form as a product previously approved
  • The drug product is an Oral Sol, Elixir, Syrup, tincture or other solubilized form and contain the same active ingredient in the same concentration as a previously approved drug product but contains low inactive ingredients known to significantly affect absorption
  • The drug product is a topically applied preparation intended for local therapeutic effect
  • The drug product is an oral form that is not intended to be absorbed e.g. radio opaque medium
  • The drug product is a solid oral form that has been demonstrated to be identical or sufficiently similar to a drug product that has met the in vivo B.A requirement
• Factors influencing B.A of Oral Drugs


  • Drug Substance physicochemical Properties: Particle Size, Crystalline or amorphous form, Salt form, Ionization, Lipid or Water Solubility, pH & pKa
  • Pharmaceutical Ingredients or Additatives/Excipients (Adjuvants): Suspending Agents, Fillers/Diluents, Surface active agent/Surfactant, Flavouring agent/Coloring agent, Binder, Coating material, Disintegrating agent, Preservative