Pharmaceutical Excipients and Ingredients Study Notes

PHARMACEUTICAL EXCIPIENTS AND INGREDIENTS

Formulation

  • Definition: A formulation is the combination of excipients and active ingredients (AI) processed using one or more manufacturing processes to yield a pharmaceutical dosage form.
  • Excipients:
    • Definition: Excipients are substances other than the active drug substances or finished dosage form that have been appropriately evaluated for safety.
    • Safety: All excipients must be demonstrated to be safe for human and veterinary use.
    • Functionality: Some excipients have shown more activity in drug absorption by influencing intestinal transporters. While they offer new opportunities for pharmaceutical scientists, there is a cautionary note on the indiscriminate enhancement of permeability, as it can lead to unwanted consequences.

FUNCTIONS OF EXCIPIENTS

  • Aid in the processing of the drug delivery system during its manufacture.
  • Protect, support, or enhance stability, bioavailability, or patient acceptability.
  • Assist in product identification.
  • Enhance overall safety, effectiveness, or delivery of drugs during storage or use.

DILUENTS

  • Definition: Diluents are ingredients incorporated into a formulation to increase the dosage form (v/w).
  • Importance: The quantity and type of diluents must depend on and match with the active ingredients to ensure satisfactory stability and performance.
  • Properties: Diluents provide desirable properties, such as good powder flow, compaction of AI, disintegration, friability, and both physical and chemical stability. Diluents comprise a large portion of solid dosage forms.
  • Common pharmaceutical tablet and capsule diluents include:
    • Calcium carbonate
    • Dicalcium phosphate
    • Lactose anhydrous
    • Lactose monohydrate
    • Mannitol
    • Sorbitol
    • Starch
    • Sucrose

BINDER

  • Definition: Binders are incorporated into formulations to facilitate the agglomeration of powder into granules.
  • Functionality:
    • They may either dissolve or disperse in granulation fluids; after evaporation of these fluids, binders typically produce dry granules with desirable properties, size, and shape.
    • Binders facilitate the production of moist granules by altering interparticle size during wet granulations.
  • Common binders used in tablet and capsule formulations include:
    • Povidone
    • Starch
    • Sodium carboxymethylcellulose
    • Hypromellose (HPMC)

DISINTEGRANT

  • Definition: Disintegrants facilitate the uptake of water into a tablet or swell in contact with water, leading to the expansion of the tablet.
  • Functionality: They are used in solid forms to promote the disruption of the mass into smaller particles that are more readily dispersed or dissolved.
  • Common examples of tablet and capsule disintegrants include:
    • Alginic acid
    • Polacrilin potassium (e.g., Amberlite)
    • Sodium alginate
    • Sodium starch glycolate
    • Starch

LUBRICANT

  • Definition: Lubricants are used to reduce frictional forces between formulation components and the metal contact surfaces of manufacturing equipment such as punches and dies.
  • Functionality: Lubricants adhere to solid surfaces and reduce both particle-particle friction and particle-equipments surface friction.
  • Caution: Excessive lubricant use can lead to retarded tablet disintegration or dissolution, resulting in large hydrophobic surfaces that will not wet or dissolve.
  • Common examples of lubricants used in capsules and tablets include:
    • Calcium stearate
    • Magnesium stearate
    • Mineral oil
    • Stearic acid
    • Zinc stearate

GLIDANTS AND ANTICAKING AGENTS

  • Definition: Glidants and anticaking agents are used to promote powder flow and reduce caking or clumping of powders stored in bulk.
  • Functionality: They help reduce the adhesive and cohesive forces between particles, along with the friction between those large particles.
  • Anticaking agents function by absorbing free moisture, preventing particle-particle bridges that cause caking.
  • Common examples include:
    • Colloidal silicon dioxide
    • Calcium silicate
    • Magnesium silicate
    • Talc

WETTING AND SOLUBILIZING AGENTS

  • Definition: These agents are amphiphilic molecules containing both polar and nonpolar regions, functioning as emulsifying, wetting, and solubilizing agents.
  • Important Properties:
    • Ability to absorb at gas-liquid, liquid-liquid, and solid-liquid interfaces to reduce interfacial tension.
    • Ability to self-associate and form aggregates or micelles, facilitating wetting or solubilization of drug substances.
  • Common examples include:
    • Lecithin
    • Poloxamer
    • Sodium lauryl sulfate

COATING AGENTS

  • Purpose: Coating agents are used to coat a tablet to protect it against decomposition by atmospheric oxygen or humidity.
  • Additional Functions:
    • Provide a desired release pattern
    • Mask taste or odor
    • Serve aesthetic purposes
  • Types of Coating:
    • Sugar coating: Sugary covering typically starts to break up in the stomach.
    • Film coating: Forms a thin cover around a tablet or bead; unless enteric, films dissolve in the stomach.
    • Enteric coating: Passes through the stomach and breaks up in the intestines; enteric coating polymers prevent dissolution in acidic pH and are insoluble in the stomach's acidic environment. Upon reaching the intestines’ higher pH, the polymers dissolve allowing the dosage form to disintegrate and dissolve.
    • Other coatings (e.g., ethylcellulose): Can be used to slow drug release in the gastrointestinal tract.
  • Examples of coating materials:
    • Methylcellulose
    • Hypromellose
    • Sucrose
    • Cellulose acetate

CONCLUSION

  • Acknowledgement: Thank you for your attention!