History of Oral Drug Delivery Systems

History of Oral Drug Delivery

• Oral drug delivery systems date back to ancient times, with the use of plant extracts and natural substances for treating ailments.
• The modern era of oral drug delivery began in the late 19th and early 20th centuries with the development of tablets and capsules.
• Compressed tablets, introduced in 1884, provided a convenient and standardized method for medicine delivery.
• Gelatin capsules, invented in 1833, allowed for more palatable and convenient administration of powders and liquids.
• Sustained-release and enteric-coated formulations were developed in the mid-20th century, enabling prolonged or targeted drug delivery, respectively.

Introduction to Oral Drug Delivery

• Oral medication is considered the most common route of drug administration.
• Advantages include convenience, patient preference, cost-effectiveness, and ease of large-scale manufacturing.
• Oral formulations represent approximately 90% of the global pharmaceutical market share for human use.
• Oral administration accounts for roughly 84% of best-selling pharmaceutical products.

Oral Drug Delivery Systems: Routes and Forms

• Digestive Tract:
  • Solid Forms: Tablets, capsules, lozenges, chewable tablets, powders, granules
  • Liquid Forms: Solutions, suspensions, emulsions
• Buccal and Sublingual:
  • Solid Forms: Oral disintegrating tablets (ODT), oral thin films (OTF), sublingual drugs
  • Liquid Forms: Mouthwashes, throat paints, gargles, oral sprays
• Respiratory Tract:
  • Solid Forms: Dry powder inhalers (DPI)
  • Liquid Forms: Anesthetic vaporizers, nebulizers, metered-dose inhalers (MDI)
  • Gases: Oxygen masks, oxygen concentrators, anesthetic machines

Advantages of Oral Drug Delivery

• Potential for extended drug action beyond treatment duration.
• Minimal training required for administration.
• Less objectionable than parenteral routes.
• Generally milder drug reactions.
• Drugs readily available through prescription.
• Simple and convenient to use.

Disadvantages of Oral Drug Delivery

• Patient non-compliance can be a concern.
• Slow absorption leading to delayed onset of drug action.
• Not suitable for emergency situations.
• Potential for nausea and vomiting.
• Not useful in highly apprehensive patients.
• Difficulty adjusting sedation levels.
• Erratic absorption can lead to unpredictable drug response.

Factors Affecting Oral Drug Delivery

• Physicochemical properties of the drug.
• pH and digestive enzymes within the gastrointestinal tract.
• Drug-drug interactions.
• Food and beverage intake.
• Dosage form.
• Genetic factors.
• Patient compliance.
• Disease state.

Ideal Properties of Oral Drug Delivery Systems

• Stability.
• Bioavailability.
• Permeability.
• Solubility.
• Targeting capability.
• Controlled release mechanism.
• Non-toxicity.
• Ease of administration.
• Cost-effectiveness.

Mechanism of Oral Drug Delivery

• Includes disintegration of dosage form, dissolution of drug in GI fluids, absorption across the GI membrane, and metabolism and elimination of the drug by the body.
• Steps: Disintegration, Dissolution, Absorption, Metabolism and elimination

Patented Formulations of Oral Drug Delivery Systems

• Patent No. | Contents
• EP2001450 (2008) | Orally disintegrating tablets with fast dissolution, optimal mechanical strength, disintegrating within 60 seconds.
• WO2006123364 (2006) | Coated tablet system with controlled drug release, where the coating is removed fully or partially after a predetermined delay.
• WO2007001448 (2007) | Coated, controlled-release polymer particles encapsulating active agents, with a mucoadhesive coating.
• WO2008075448 (2008) | Chitosan coating solution deemed safe for oral administration in food and medicine.
• US2008293787 (2008) | Solid dispersions of poorly soluble compounds formed by co-precipitation, improving stability.

Marketed Formulations of Oral Drug Delivery Systems

• Extended-release tablets and capsules: OxyContin (oxycodone), RitalinLA (methylphenidate), Glucophage XR (metformin)
• Oral disintegrating tablets: Zofran ODT (ondansetron), Claritin Reditabs (loratadine)
• Liquids and suspensions: Amoxicillin Oral Suspension, Dimetapp Elixir
• Chewable tablets: Tums (calcium carbonate), Children's Tylenol Chewable (acetaminophen)
• Orally disintegrating films: Suboxone Film (buprenorphine and naloxone), Zuplenz (ondansetron)

Solid Dosage Forms

• Capsules: Solid dosage form containing the drug within a hard or soft gelatin shell. Example: Feroglobin capsules (iron supplements).
• Lozenges: Hard, oval, solid dosage forms with drug in a flavored sugar base. Dissolves in the mouth for local therapeutic effects. Example: Sore Throat lozenges.
• Powders: Finely ground mixtures of dry drugs and inactive ingredients, used topically or internally.
• Granules: Larger than powders, wetted, dried, and ground into coarse, irregularly shaped pieces.

Liquid Dosage Forms

• Liquid dosage forms containing active ingredients in a liquid vehicle, such as:
  • Solutions: Homogenous mixtures of dissolved medications in a liquid vehicle. Example: Paracetamol syrup (fevadol).
  • Suspensions: Mixture of undissolved, very fine solid particles distributed through a liquid. Example: Amoxicillin suspension.
  • Emulsions: Semi-solid dosage forms, mixture of two immiscible substances. Example: Castor oil emulsion as a laxative.

Sublingual/Buccal Drug Delivery

• Sublingual (under the tongue) and buccal (between cheek and gum) routes of administration are used for rapid onset of action.
• Medications are absorbed directly by blood vessels, bypassing the first-pass effect.
• Example of sublingual tablet: Nitroglycerine (Anti-Angina)
• Example of buccal tablet: Fentanyl buccal tablets (Narcotic)

Future Aspects of Oral Drug Delivery

• Nanotechnology: Use of nanoparticles to enhance bioavailability and efficacy, protecting drugs from degradation and improving absorption.
• Smart drug delivery systems: Respond to specific stimuli like pH or temperature changes, releasing drugs at targeted locations.
• 3D printing: Personalized oral drug delivery systems, tailoring dosages and formulations to individual needs.
• Biodegradable materials: Reduced environmental impact and improved safety in oral drug delivery systems.
• Microbial-based delivery systems: Using probiotics to deliver drugs orally, leveraging their ability to survive harsh GI conditions.

Conclusion

• Oral drug delivery is essential in modern medicine, offering safe and effective drug delivery to patients.
• Advantages include convenience, ease of use, and improved patient compliance.
• Advancements in drug formulations and delivery technologies contribute to enhanced efficacy, safety, and patient outcomes.

Explore the evolution of oral drug delivery systems from ancient remedies to modern tablets and capsules. This quiz covers key developments like the introduction of compressed tablets and gelatin capsules, as well as advancements in sustained-release formulations. Discover how these innovations have shaped the pharmaceutical landscape.