Industrial Pharmacy II - Lecture 2

Industrial Pharmacy II - Lecture Notes

• Lecture 2: Focuses on pharmaceutical dosage forms, their classification, manufacturing stages, tablet dosage forms, advantages and disadvantages of tablets, types of tablets, and tablets used in the oral cavity.

What is Pharmaceutical Dosage Form

• Defined as a combination of drug (API) and excipients in a specific configuration.
• Drug is the active pharmaceutical ingredient that alters biological conditions.
• Excipients are inactive materials involved in manufacturing, storage, and formulation use.
• Advantages of dosage forms include delivering the right amount of drug conveniently and acceptably to patients.
• Dosage forms enable control of drug delivery (e.g., fast-onset, extended-release).

Classification of Dosage Forms

• Based on Route of Delivery: Pulmonary, Parenteral, Transdermal, Nasal, Ophthalmic, Otic, Vaginal, Rectal, Oral.
• Based on Physical Form: Solid, Semisolids, Liquid, Gaseous.

Stages of Manufacturing a Dosage Form

• Pre-formulation Stage: Preliminary studies to identify the physical and chemical properties of the medicinal substance to determine efficacy and bioavailability of the candidate dosage form.
• Evaluation of particle size, solubility, stability, excipient compatibility, and crystal/surface properties.
• Biopharmaceutical Studies: Discover the rate and extent at which candidate drug will be available at the site of action (includes pharmacodynamic, pharmacokinetic, and product analysis studies).
• Formulation and Development: Involve the actual formulation of the desired dosage form. Other studies include patient compliance, cost of manufacturing, and stability analysis.

Tablet Dosage Form

• Oral route is the most important method of administering drugs for systemic effects.
• About 90% of drugs are administered orally.
• Tablets are the most common form of orally administered dosage forms.
• Tablets consist of API and excipients.
• Characteristics can vary in size, shape, weight, hardness, thickness, disintegration, and dissolution.
• Tablet preparation usually involves compression.

Advantages of Tablets

• Unit dosage form: provides accurate dosage measurement.
• Relatively lightweight and compact.
• Easy to handle, store, and dispense.
• Easier to package and ship than capsules.
• Relatively inexpensive manufacturing cost.
• Identification is generally simple.
• Ease of swallowing
• Good for large scale production
• Good stability (chemical, mechanical, microbiological).
• Easy to control and manipulate drug release

Disadvantages of Tablets

• Some drugs resist compression into a dense compact.
• Not ideal for masking bad tastes or smells.
• Can be difficult for drugs with poor wetting properties and slow dissolution rates.
• Some drugs may degrade when administered orally.

Types of Tablets

• Compressed tablets (plain tablets): Uncoated tablets designed for rapid disintegration and drug release. Intended for local GI effects (antacids, adsorbents), and systemic circulation (e.g., ibuprofen).
• Multiple compressed tablets: Layered tablets or compression-coated tablets. Contain two or more components separated and are intended to separate physically or chemically incompatible ingredients, or create multiple or prolonged action products.
• Drawbacks of Multiple compressed tablets: slower production speed, difficult to control the release of each layer.
• Chewable tablets: Designed to be chewed before swallowing, mainly used for children or those who struggle with swallowing. Excellent for masking bad taste or requiring larger doses.
• Sugar-coated tablets: Sugar coating masks odor and taste, good for aesthetics, and dissolves quickly.
• Film-coated tablets: Developed as an alternative to sugar coating, provides elegant appearance, sometimes better mechanical strength and sometimes modified-release properties.
• Repeated-action tablets: One type of extended-release dosage form, designed for controlled release of medication over time (e.g., antiallergic medications)
• Delayed action and enteric-coated tablets: Designed to protect the stomach from drug irritation, dissolve in the small or large intestine, coated by a shell that resists gastric acid dissolution. Preservation against stomach acid. (e.g., aspirin)
• Buccal and sublingual tablets: Dissolve in the mouth, rapidly deliver medication to systemic circulation, via the oral mucosa, avoiding first-pass metabolism (e.g., nitroglycerin).
• Troches and lozenges: Used in the mouth or throat, dissolve slowly (e.g., cough drops)
• Dental cones: Used in tooth extraction sites, provide slower sustained release of antibacterial agent.

Tablets Used to Prepare Solutions

• Effervescent tablets: Designed to create a solution by rapidly releasing carbon dioxide. Suitable for masking bad taste and are easy to adjust pH. Often contain citric acid and sodium bicarbonate.
• Dispensing tablets: Used to create solutions for a specific concentration of other drugs.
• Hypodermic tablets: Used to create injectable solutions.

Ideal Tablet Characteristics

• Elegant appearance.
• Resistance to physical damage.
• Chemical and physical stability during shelf-life.
• Predictable and reproducible release of the medicinal agent(s).
• Suitable chemical stability.

Properties of Tablet Ingredients

• Nontoxic: Be legal in the market area.
• Commercially available
• Reasonable cost
• Must be physiologically inert
• Stable in preparation (with other components).
• Absence of contaminations.
• Color compatibility (does not cause off-colors)
• Non-alteration of bioavailability

Tablet Excipients

• Antioxidants: Prevent drug deterioration.
• Antiadherents: Prevent sticking.
• Binders: Cause adhesion amongst particles.
• Diluents: Fillers to achieve bulk.
• Disintegrants: Promote disruption into smaller particles.
• Glidants: Improve powder flow.
• Lubricants: Reduce friction.

Tablets Administered by Other Routes

• Implantation tablets: Designed for prolonged release of medication, usually subcutaneous.
• Vaginal tablets: For vaginal use, slow dissolution and drug release in the vaginal cavity.