Topic : Compression & Consolidation Subject (course): Biosciences Engineering and Allied (Pharmacy) Topic : Compression & Consolidation 2. Have anyone of you ever done a screencast for your class? No Learning Objectives: Understanding Planning Detailing Organizing

Topic : Oral Drug delivery Subject (course): Biosciences Engineering and Allied (Pharmacy) Topic : Oral Drug delivery 2. Have anyone of you ever done a screencast for your class? Yes Learning Objectives: Recall Understanding Apply

4. Planning Introduction Mechanism of compression consolidation Importance of compression consolidation Factor affecting compression consolidation

COMPRESSION: “Compression is the process of applying pressure to a material”.  In pharmaceutical tableting an appropriate volume of granules in a die cavity is compressed between an upper and a lower punch to consolidate the material into a single solid matrix, which is subsequently ejected from the die cavity as an intact tablet. COMPACTIBILITY: “The ability of powder bed to cohere into or to form a compact or it is the ability of powder material to be compressed in to a tablet of specified tensile strength.” CONSOLIDATION: “Consolidation is an increase in mechanical strength of material from particle- particle interaction.”

Mechanism: I. Cold welding: II. Fusion welding: i. Cold welding iii. Recrystallization I. Cold welding: When the surface of 2 particles approach each other closely enough <50 nm, their energies result in a strong attractive forces. This mechanisms is cold welding. II. Fusion welding: When load is applied, frictional heat can be generated. If this heat is not dissipated, the local rise in temperature could be sufficient to cause melting of the contact area of the particles, which would relieve the stress in that particular region. In that case, the melt solidifies giving rise to fusion bonding.

III. Recrystallization: The actual solubility of solid also depends somewhat on the applied pressure, so that if a film of moisture is present on the solid surface then the high pressure at the point solid contact could force more material into solution. This dissolved solid would crystallize on relief of the applied stress to form a solid bridge whose strength would partly depend on the rate of recrystallization. In general, slow rate should produce a more prefect crystal structure with consequent higher strength. Factors Affecting Consolidation process: Chemical nature of material The type and degree of crystallinity in a particular material influences its consolidative behaviour under appreciable applied force. Extent of available surface The compressional process is affected by the extent of available surface. Presence of surface contaminants Inter-surface distance

Fig: Effect of increasing compressional force on specific area of powder mass When a powder mass is subjected to increasing compressional force, there is initial particle fracture, which gives rise to increased surface area(O to A). At the point A, particles re-bonding becomes dominant factor, and from then on surface area decreases unless tablet lamination begins.

Topic : Oral Drug delivery Subject (course): Biosciences Engineering and Allied (Pharmacy) Topic : Oral Drug delivery 2. Have anyone of you ever done a screencast for your class? Yes Learning Objectives: Recall Understanding Apply

4. Planning Introduction Mechanism of compression consolidation Importance of compression consolidation Factor affecting compression consolidation

Tablets: A tablet is a hard, compressed medication in round, oval or square shape. Types of tablets: 1- Disintegrating tablet (conventional or plain tablet) Disintegrating tablet is the most common type of tablets that is intended to be swallowed.

Types of Tablets (Cont.) Single layer tablet

Types of Tablets (Cont.) 2- Chewable tablets Chewable tablets are to be chewed and thus mechanically disintegrated in the mouth. Advantages of chewable tablets: Provide quick and complete disintegration of the tablet and thus obtain a rapid drug effect - Easy administration, especially for infants and elderly people.

Types of Tablets (Cont.)

Types of Tablets (Cont.) 3- Effervescent tablets - Effervescent tablets are dropped into a glass of water before administration during which CO2 is liberated.

Types of Tablets (Cont.) Advantages of effervescent tablets: 1- To obtain rapid drug action, for example analgesics and antacids.

Types of Tablets (Cont.)

Types of Tablets (Cont.) 2- To facilitate drug intake, for example vitamins

Types of Tablets (Cont.) 4- Sublingual and Buccal tablets They are used for drug release in mouth followed by systemic uptake of the drug. A rapid systemic drug effect can thus be obtained without first-path liver metabolism. Sublingual tablets are placed under the tongue.

Types of Tablets (Cont.)

Types of Tablets (Cont.) Buccal tablets are placed in the side of the check for absorption through oral mucosa.

Types of Tablets (Cont.) 5- Lozenges They are tablets that dissolve slowly in the mouth and so release the drug dissolved in the saliva. Lozenges used for - Local medications in the mouth or throat, e.g. local anaesthetics, antiseptics and antibiotics.

Types of Tablets (Cont.) Hard candy lozenges, e.g. Halls®