History and Systems of Oral Drug Delivery

History of Oral Drug Delivery

• Use of plant extracts and natural substances for treatment dates back to ancient times.
• 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 were introduced in 1884 for convenience and standardization.
• Gelatin capsules were invented in 1833 for easier administration of powders and liquids.
• Sustained-release and enteric-coated formulations emerged in the mid-20th century for prolonged or targeted drug delivery.

Introduction to Oral Drug Delivery Systems

• Oral medication is the most common drug administration route due to convenience, patient preference, cost-effectiveness, and ease of manufacturing.
• Around 60% of commercially available small-molecule drug products are orally administered.
• Oral formulations represent about 90% of the global market share for human pharmaceutical formulations.
• 84% of the best-selling pharmaceutical products are orally administered, valued at $35 billion with an annual growth rate of 10%.

Oral Drug Delivery System: Digestive Tract

• Solid forms include tablets, capsules, lozenges, chewable tablets, powders, and granules.
• Liquid forms include solutions, suspensions, and emulsions.

Oral Drug Delivery System: Buccal and Sublingual

• Solid forms include oral disintegrating tablets (ODT), oral thin films (OTF), and sublingual drugs.
• Liquid forms include mouthwash, throat paints, gargles, and oral sprays.

Oral Drug Delivery System: Respiratory Tract

• Solid forms include dry powder inhalers (DPI).
• Liquid forms include anesthetic vaporizers, nebulizers, and metered-dose inhalers (MDI).
• Gases include oxygen masks, oxygen concentrators, and anesthetic machines.

Advantages of Oral Drug Delivery Systems

• Duration of action may extend beyond treatment period.
• Requires minimal training.
• Less objectionable than parenteral routes.
• Drug reactions are generally less severe.
• Drugs are readily available by prescription.
• Simple and convenient to use.

Disadvantages of Oral Drug Delivery Systems

• Patient noncompliance.
• Slow absorption and delayed onset of action.
• Not suitable for emergencies.
• May cause nausea and vomiting.
• Not effective for apprehensive patients.
• Level of sedation cannot be easily adjusted.
• Erratic absorption makes response unpredictable.

Factors Affecting Oral Drug Delivery

• Physicochemical properties of the drug.
• pH and digestive enzymes.
• 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.
• Controlled release.
• Non-toxicity.
• Ease of administration.
• Cost-effectiveness.

Mechanism of Oral Drug Delivery Systems

• Involves disintegration of the dosage form, dissolution in GI fluids, absorption across the GI membrane, metabolism, and elimination by the body.

Patented Formulations of Oral Drug Delivery Systems

• EP2001450 (2008): Orally disintegrating tablets dissolve quickly, have optimal mechanical strength, and disintegrate within 60 seconds.
• WO2006123364 (2006): Coated tablet with delayed release mechanism for controlled drug release.
• WO2007001448 (2007): Coated controlled release polymer particles with mucoadhesive coating for enhanced absorption.
• WO2008075448 (2008): Chitosan coating solution for safe oral administration in food and medicine.
• US2008293787 (2008): Solid dispersions of poorly soluble compounds formed by co-precipitation for improved stability.

Marketed Formulations of Oral Drug Delivery Systems

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

Solid Dosage Forms

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

Liquid Dosage Forms

• Contain one or more active ingredients in a liquid vehicle like solutions, suspensions, or emulsions.
• Solutions: Homogenous mixture of dissolved medication in a liquid vehicle. Example: Paracetamol syrup (fevadol).
• Suspensions: Mixture of undissolved, fine solid particles distributed in a liquid. Example: Amoxicillin suspension.
• Emulsions: Semi-solid dosage form where two unbendable substances are mixed. Oil-in-water (O/W) emulsion contains small amount of oil in water. Water-in-oil (W/O) emulsion contains small amount of water in oil. Example: Castor oil emulsion as laxative.

Sublingual/Buccal Drug Delivery Systems

• Sublingual (under the tongue) and buccal (between the cheek and gum) routes are used for rapid onset of action.
• Medication is absorbed directly by blood vessels under the tongue or in the lining of the mouth, providing fast action and bypassing first-pass effect.
• Example of sublingual tablet: Nitroglycerine (Anti-Anginal).
• Example of buccal tablet: Fentanyl buccal tablets (Narcotic).

Future Aspects of Oral Drug Delivery Systems

• Nanotechnology: Nanoparticles for enhanced bioavailability and efficacy. Nanoparticles protect drugs from degradation and improve absorption.
• Smart Drug Delivery Systems: Respond to specific stimuli like pH or temperature for targeted drug release and reduced side effects.
• 3D Printing: Personalized oral drug delivery systems tailored to individual needs.
• Biodegradable Materials: Reduce environmental impact and improve safety.
• Microbial-based Delivery Systems: Probiotics to deliver drugs orally. Probiotics survive harsh GI conditions and could improve drug delivery to the gut microbiome.

Conclusion

• Oral drug delivery systems are crucial in modern medicine for safe and effective drug delivery.
• Advantages include convenience, ease of use, and improved patient compliance.
• Advancements in novel drug formulations and innovative technology have improved drug efficacy, safety, and patient outcomes.

Explore the evolution of oral drug delivery from ancient plant extracts to modern formulations. This quiz covers significant milestones in drug administration, including the creation of tablets, capsules, and advanced delivery systems. Test your knowledge on the impact of oral medications in the pharmaceutical industry.