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79 Cards in this Set
- Front
- Back
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What is the difference between a drug and the dosage form?
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A drug is the active ingredient (API - Active pharmaceutical Ingredient).
The Dosage Form is the form that the drug is taken in. (i.e. tablets, capsules, syrups...) |
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What is pre-formulation?
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Studies done before processing the drug into the dosage form. i.e. Drug-excipient compatabilites
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What information do we need to know in order to formulate a drug?
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1.Physical characteristics of drug.
2. Intended route of drug administration 3. Drug Stability 4. Drug-excipient Compatability |
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What steps are involved in pre-clinical work?
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1. Discovery of a new chemical entity (NCE)
2. Pre-formulation studies 3.Formulation studies 4. Animal testing |
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What steps are involved with clinical work?
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1. Phase I, II, III(human trial)
2. If phase III is successful, drug comes to market. 3. Phase IV, drug can be recalled. |
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Physical description involves what?
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Solid (i.e. Is the powder crystalline/amorphous?)
Liquid (i.e. Is the liquid volatile?) Gas |
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What does microscopic examination tell us about the substance?
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1. Particle Size
2. Particle Size distribution 3. Particle Shape 4. Crystal/Amorphous Structure |
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What is polymorphism?
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A drug can exist in multiple forms
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What factors could be impacted by polymorphic structures?
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1. Strenght of material
2. Particle Size 3. Solubility 4. Dissolution 5. Stability |
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What are solids that don't melt, but show a differnt transition?
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Amorphous solids
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Crystal A has a melting point of 120C while crystal B has a melting point of 270C. Which crystal is more stable?
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Crystal B is more stable because it requires more energy to break the bonds.
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The total number of particles that go into solution after an infinite period of time. Temperature is a factor.
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Solubility
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What are the factors that affect solubility?
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1. Temperature
2. pH of solution 3. Crystal Structure 4. Particle Size |
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What is the process by which a drug dissolves?
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Dissolution
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How is the partition coefficient determined?
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K = conc. of drug in octanol/conc. of drug in water
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What is the Noyes-Whitney equation used to find?
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Diffusion and Permeability
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Ionized ---> more soluble
Unionized ---> more permeable |
True
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What is the concentration of H2O?
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55.3 moles/L
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What is neutral pH at 37C?
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6.8
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What two steps are important in the targeting of drug molecules?
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1. Penetrate the SOA in adequate concentration.
2. Avoid distribution in unwanted ares. |
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What concentrations does the therapeutic window exist between?
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Minimum Toxic Concentration and Minimum Effective Concentration
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What is the science of flow?
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Rheology
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Considering Newtonian Flow, what can be predicted if viscosity is given?
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The rate of flow can be predicted.
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1. Exhibits solid-like behavior initially.
2. The point at which it breaks down = yield value. 3. Once it flows, it is Newtonian behavior. |
Features of a Non-Newtownian material
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What are the three types of Non-Newtonian materials?
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1. Simple Plastic
2. Pseudo Plastic 3. Dilatant |
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What material is characterized by shear-thinning systems?
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Pseudoplastic Flow
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What material is characterized by shear thickening flow?
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Dilatant Flow
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What kind of material could be considered a subset of simple plastic and pseudoplastic?
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Thixotropic material
(Shear thinning behavior induced upon stress) |
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What type of viscometer is used to measure the viscosity of Non-Newtonian materials?
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Cone and Plate viscometer
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What type of viscometer is used to measure the viscosity of thin liquids?
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Ostwald Viscometer
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What are semi-solid dosage forms intended for topical application?
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ointments, creams, and gels
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What is an emulsion?
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It is a liquid suspended in a liquid. They key is to have two immiscible liquids.
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Contain hydrocarbons, oils, waxes, or petrolatum
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Oily Base (Oleaginous base)
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Absorption bases - capable of aqueous base absorption. Needs surfactant
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Water in oil emulsion
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Water removable bases. Hydrophilic ointment used. (USP)
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Oil in water emulsion
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Greaseless bases. Polyethylene glycols
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Aqueous Bases
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True or False?
If you are looking for a local effect, absorption is desireable. |
False
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1. Want uniform product
2. Non-gritty product 3. Flow properties 4. Stability of the formulation |
Objectives for preparing ointments
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What are the three layers of the epidermis?
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1. Stratum Corneum (main barrier)
2. Stratum Lucidum 3. Stratum Granulosum |
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Protein lysed by salicylic acid.
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Keratinized cells of the stratum corneum
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This layer of the epidermis is very hydroscopic. It absorbs 4-5 times its weight in moisture.
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Stratum corneum
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Considering an ointment in a tube, is thixotropy desired?
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No, a simple plastic or pseudoplastic consistency would be desired.
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Considering a cream or lotion, would thixotropy be desired?
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Yes
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What type of consistency do gels have?
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They have simple plastic consistency.
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Are preservatives usually added to water-containing ointment bases or to oleagenous bases?
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Preservatives are added to water-containing bases. Usually oleagenous bases do not require preservatives.
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What are the two preparation methods to make an ointment/cream/gel
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1. Incorporation Method
2. Fusion Method |
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What are the steps influencing percutaneous Absorption?
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1. Dissolution of drug in the vehicle. (crystaline or amorphous???)
2. Diffusion through the skin 3. Absorption inside the skin |
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Most commercial patches have an occlusion barrier. What is this used for?
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The barrier traps moisture. When hydration increases, absorption increases.
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What are some methods of permeation enhancers?
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1. Increase hydration (polypropylene glycol)
2. Decrease consistency of lipoprotein matrix 3. Increase driving force for the drug. |
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1. Sonication
2. Electric Current 3. Temperature |
Ways to increase the driving force for the drug.
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Why is dermal clearance important?
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If clearance is low, then absorption is low.
If clearance is high, then absorption is high. |
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Why is it important to rotate the site of the dermal system?
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1. minimize irritation
2. Dermal clearance |
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Unit for Shearing Stress
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F/A
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Unit for rate of shear
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dV/dr
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ή
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Viscosity
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Shear thinning behavior induced upon stress. Stays for 10-20 minutes even after the stress is removed.
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Thixotropic materials
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1. Site of application is important (stratum corneum can't be too thick)
2. Rotate the site 3. surface free of sebum/sweat 4. no defilatory creams/keratolyics 5. No hair at site 6. Do not alter package in any way. |
Considerations for transdermals
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What are vaginal suppositories called?
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Pessaries
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What are urethral suppositorries called?
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Bougies
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Melt/soften/Dissolve at body Temperature?
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Important features of suppositories
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What are some local effects of rectal suppositories?
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1. Used mostly for to relieve constipation.
2. antihemorrhoidal 3. local anestetics/vasoconstrictors/astringents/analgesics/emollients/protectives |
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What is a system that coats a surface?
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Emollient
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What are vaginal inserts used for?
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1. Contraceptives
2. Antiseptics used in feminine hygiene |
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What are urethral suppositories used for?
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1. Antibacterial agents
2. Antiseptics in urethral examination |
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What are some examples for systemic uses of suppositories?
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1. Relief from nausea and vomitting
2. Analgesia 3. Relief from migraine 4. analgesic/antipyretic |
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1. Anorectal Physiology
2. Colonic Content 3. Circulation Route 4. pH/Buffering capacity |
Factors affecting Systemic absorption of suppositories
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Which has the larger surface area; Large intestine or rectum?
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Large intestine has significantly larger surface area.
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Where do the upper, middle, and lower hemorroidal veins surrounding the rectum transport the blood?
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The upper veins carry blood to the portal system.
The lower and middle veins bypass the portal system. |
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Why would you use and enema before inserting a suppository?
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The enema is used to evacuate the colon, and there is much greater absorption from a void colon.
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1. non-toxic/non-irritating to mucous membranes
2. compatible with a variety of drugs 3. Melt or dissolve in body fluids 4. Stable upon storage |
Characteristics of Suppository Bases
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Type of oleaginous suppository base
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Cocoa Butter (also called Theobroman oil)
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Type of water soluble suppository base
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Polyethylene Glycols (PEG)
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What is the difference between the alpha and beta polymorphs of cocoa butter?
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The alpha has a MP of 30C and the beta has a MP of 35C. The beta form is preferred.
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How can we avoid preparing the alpha form during formulation?
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Never exceed 50C during formulation.
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PEG with a MW of 400
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Liquid
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PEG with a MW of 1000-1600
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Semi-solid
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PEG with a MW of 1600
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Solid Powder
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What are the three ways to prepate a suppository?
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1. molding
2. compression 3. Hand rolling/shaping |
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What are the steps for preparing a suppository by molding?
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1. Melt the base
2. Incorporate desired drug 3. Pour into prelubed molds 4. Allow the melt to cool/congeal 5. removal/packaging/labeling |
