Dosage Forms Flashcards
Ideal Dosage Form Examples
1 dose is a manageable size, stable, convenient, release to receptors in timely fashion and palatable
Tablet Def.
Solid dosage form containing medicinal substances with/without suitable diluents. Drugs are mixed with other constituents and crushed
Tablet Routes
Oral, buccal, sublingual and vaginal
Tablet Physical Form
Solid suspension and solid solutions
How course dispersion is controlled
intermolecular bonds in powder
Why are tablets so inflexible in dosing
Drug isn’t evenly distributed in tablet
Absorption In Oral Cavities
rapid disintegration (sublingual), prolonged release (buccal tablet) and multidirectional (buccal)
Why is masking tablet taste important
Improving patient acceptance. Use synthetic sweeteners as they are more effective.
What does the coating on a tablet do
mask taste and avoid degradation
Max. tablet size for adults
500mg
How are tablets retained in mouth
Mucoadhesive and Bio-adhesive
Bio-adhesive Function
Adhesive binds to cell
Who can not take tablets
Children (don’t have strong swallow reflex) and Elderly (swallow reflex, struggle with packaging)
Capsule Def.
Solid dosage form consisting of hard/soft shell (gelatin/starch/cellulose) and solid/liquid filling
Capsule Routes
Oral, buccal
Capsule Physical Form
Solid suspensions/ solutions in shell
How Capsule Shells Effect Dosage Form
Mask taste and time lags (longer to dissolve)
Why can’t drug capsules be opened
Pharmacological factors have would be altered. Unsafe as new properties weren’t studied
Oral Liquid Dosage Form Def.
Fluid dosage form intended for delivery via oral route. Only route is oral
Oral Liquid Dosage Form Physical
Liquid, solutions, suspensions, emulsions
Oral Liquid Dosage Form Advantages Over Tablets
faster absorption, flexible to dose adjustment and suitable for the elderly
Oral Liquid Dosage Forms Disadvantages To Tablets
Less stable (transported as a powder), less palatible (no coating)
Injection Def.
Sterile preparation for parenteral (solution, emulsion, suspension or colloidal dispersion)
Injection Routes
IV, SC, IM, IU, ID, IA, IP
Pyrogen Def.
Matter of dead bacteria
What route of injection can’t use suspensions
IV
Injection Benefits
Immediate action with susutained release, release can be prolonged depending on dosage form makeup (suspensipon/ oily sol.) /type of admin
Injection Disadvantages
Must be kept sterile (expensive, laborous, patient inability), mixing/ dilution causes precipitation, devices are vital
Patch Def.
Adhesive (stronger then plaster) applied externally to body. Ingredients move by diffusion/active transport. Both local and systemic
Patch Admin Route
Transdermal, needs excipient penetration inhancers. Develops a reservoir on skin. Area covered by patch is proportional to amount of drug administerd at time
Patch Physical Form
Non-aqueous solutions/suspensions
Patch Benefits
Easy to terminate, contains excess drug to ensure uniform dose, easy to admin
Patch Disadvantages
Can be easily incorrectly stored/ thrown out, can be irritant
Drops Def.
Solution that is administered in spherical shape. Must be below a certain size as surface tension creates drops of a size that would irritate the eye
Surphantics Function
Excipient that reduces effect of surface tension. Allowing for smaller sized drops to be formed (less irritation)
Drops Admin Route
Nasal, ocular, otic (in ear)
Drops Physical Form
Solutions and Suspensions
Drops Dosage form considerations
Isotonic, pH 4.5-8, <10 micro-litres, sterile (preservatives for multidose), frequent dosing necessary
What happens when drop irritates eye
Resulting blink removes 90% of dosage form from eye through the nasal-mactraml duct (tasted at back of throat)
What is an innovation from eye drops
Solution is removed from container. Once it makes contact with eye solution forms gel
Spray Def.
Gas converted to liquid droplets through orifice (eg squeeze bottles). Droplets are big so they don’t enter lungs
Spray Routes
Nasal, Pulmonary, Otic, Sublingual, Throat
Spray Physical Form
Solutions and suspensions
3 Forms of Spray Admin
Squeeze bottle, rhinal tube (patient’s exhalation produces force), metered dose device (propellent provides force)
Nasal Pharmaceutics Dosage Form Considerations
Isotonic, preserved, droplets size is less then 10 micro-meter
Suppository Def.
Solid body of various weights and shapes (thin top for easy insert and thick bottom for good retention).
Suppository Routes of Admin
Rectal, Urinal, Vaginal
Aerosol Def.
Fine solid/liquid dispersed particles in air/gas
Aerosol Routes of Admin
Oral cavity, pulmonary, nasal
Aerosol Physical Form
Solutions, colloidal dispersion, suspension
Dosage Form Considerations
Device used to admin (powder inhaler, meter dose inhaler, nebulisation (aqueous suspensions). Droplet size. Needs to be big enough to deposit on lungs but samll enough to not be caught in bronchioles
Multi Dose Inhaler Meachanisms
Canistar has high pressure vapour. Propellent forms liquid. Once acctuater is pushed gas pulls liquid out of orafice dispersing fine droplets in air. fine droplets tend to move together to form a bigger droplet (decraesing surface area exposed to air)
Ointment Def.
Semisolid. Contains water, volatiles and hydrocarbons, waxes or polyols as vehicle.
Ointment Admin Routes
Topical, ocular, transdermal, nasal, rectal, oral cavity and vaginal
Ointment Considerations
Greater drug retention then creams, hydrocarbon based, occlusive (keeps water on skin) and emollient (moisturizing)
Cream Def.
Emulsion, semi-solid. Contains water, volatiles and hydrocarbons, waxes or polyols as vehicles
Cream Admin
Topical, transdermal, occular, nasal, rectal, vaginal and oral cavity
Cream Physical
Emulsion
Cream consideration
better patient compliance then ointment, emusifier excipients, low occlusive (water in cream evaporates, reduced using non-volatile solvents) and sensitive to physical instability
Gel Def.
Semisolid. Liquid dispersion with stiffening gelling agents. May contain suspended particles
Gel Admin
Topical, ocular, transdermal, nasal, rectal, vaginal, oral caity and parenteral
Gel Physical
Colloidal Dispersion
Gel considerations
Gelling agent excipient, preservation required for physical stability and non-occlusive
Solution/molecular dispersion Def.
Substances mixing on the molecular level. All 1 phase (even particle distribution). Transparent and thermodynamically stable. Smallest particle size
Colloid/fine dispersion Def
Macromolecules forming bonds with water (too big to be solution) or micromolecules suspended in solution (too small to be suspension). Can scatter lights of certain wavelengths
Suspension/Coarse Dispersion Def.
Solid particles disperesed in water, no molecular bonds. Heterogenous. Scatters light and is not thermodynamically stable. Eg emulsion
Dosage Form Design Influences
Water solubility + dissolution, lipophilicity, molecular weight, Organoplectic (how it acts on organs) properties, stability, target receptor location, SElectivity and Processing/ manufacturing requirements
Steps In Drug Reaching Active Site
Admin, liberation, absorption, distribution and elimination
What is the only form drugs can be absorbed in (and thus all processes after)
They have to be in solution
Absorption Def
Diffusion of drug across epithelial barrier into blood stream
2 Ways of Absorption
Paracellular (between cells) and Transcellular (through cell)
Molecular Dispersions (Solutions) Def
Homogenous mix of 2 or more substances. Bonding occurs at molecular level. Particles are smallest (< 1nm). White light passes through
Fine Dispersions (Colloid) Def
Micro-heterogenous liquid. Moderate particle size (nanoparticles). Can scatter light of different wavelengths
Rough Dispersions (suspensions and emulsions)
Heterogenous liquid
Emulsion Def
Coarse dispersion of a liquid dispersed in a continuous liquid phase
What it the only form of dispersion that can be pharmacologically active
Molecular. Only one that can be absorbed
