PHU11104 - Short Q answers

3 types network forming colloids in hydrogels

linear / platelet / spherical

why theobroma oil must not be overheated

causes isomerisation / beta form melting point is 34.5 degrees / alpha form melting point is 19 degrees / beta form forms directly after melting 33-36 or from alpha and gamma forms after 7 days / lowers melting point

4 disadvantages of gelatin (give rise to alternative hard capsule shell materials like hpermellose)

dietary restrictions / strict regulations are costly / possibility of disease like BSE / not aesthetically pleasing

3 excipients incompatible with hard gelatin shell capsules

cationic surfactants / ethanol / glycerol

why mixtures of gelatin a and b incompatible at certain pH values

partial acid hydrolysis occurs to type A / partial alkaline hydrolysis to type B / different isolelectric points - type A alkaline, type B acidic (due to hydrolysis of glutamine and asparginine)

4 types impurities found in potable water

particulate matter / fully dissolved impurities / colloidal matter / microorganisms

definition purified water in bulk pH.eur

clear, colourless, odourless and tasteless liquid prepared from suitable portable water either by distillation or treatment with ion exchange materials or any other suitable method

haemodialysis process

blood circulated outside the body and cleansed in a dialysis machine before returning to the patient (2 parts of machine one for blood and one for dialysate / thin semi permeable brain / waste in blood passes through microscopic pores and washed away / clean blood returned to patients)

example of pyrogens

endotoxins

why limit of bacterial endotoxin content in water used for haemodialysis

patients exposed to much higher levels of water during haemodialysis than normal and have impaired kidney function so they cannot get rid of toxins that may be present / purified water should be used / pyrogens such as endotoxins cause febrile reactions if injected

5 stratergies to imrpove solubility of poorly soluble drug to be incorparated into an oral solution preparation

co solvency / ph control / solubilisation / complexation / chemical modification

preservative defintion

chemical agents that prevent growth of microorganisms in the product thereby rendering it safe in use and increasing its shelf life / prevent substance decomposing from microbial growth or other undesirable chemical changes / aqueous solutions have moisture rich environment which facilitate microbial growth

3 things microorganisms may cause

undesired visible growth / chemical changes / associated with health hazards

pharmaceutical elixir

clear, flavoured liquids containing one or more active ingredients dissolved in a vehicle that contains a high proportion of sucrose or a suitable polyhydric alcohol and may also contain ethanol or a dilute alcohol

why cannot crush tablets/capsules x2

difficult to ensure capsule dose has been taken / nurses handling powdered drugs may present health hazards

why surfactants added to suspensions

aid dispersion of suspending agent by decreasing the contact angle between solid and liquid

2 examples anionic surfactant

potassium laurate / sodium lauryl sulphate

1 example cationic surfactant

quarternary ammonium halides

1 example ampholytic/zwitterionic surfactants

sulphobeatines

2 examples non ionic surfactants

polysorbates / cetomacrogol

3 causes hardness in water

significant quantities of calcium and magnesium salts / temporary hardness due to bicarbonates which are converted to carbonates upon heating / permanent hardness due to dissolced chlorides, nitrates and sulphates (do not cause hardness upon heating)

3 reasons hard water a problem

calcium affects gelling powder of alginate and pectin dispersions / colour of pharmaceutical mixtures varies due to variation in water ph / precipitates form when hard water used

pyrogen definition

of bacterial origin and consist of lipids associated with a polysaccharide or protein or both

example of fibrogens and what cause if injected

endotoxins / cause febrile reactions

thixotrophy definition

decrease in apparent viscosity as a function of time upon shearing, followed by gradual recovery when the shear is removed

3 inorganic gelling agents used in preparation of hydrogels

fumed silica / bentonite / aluminium or magnesium silicate

5 fundamental SI units

metre / kilogram / litre / candella / moles

degree of substitution of cellulose derivatives

average number of substituted hydroxyl groups per glucose molecule

why effervescent granules heated during production

remove water of crystallisation

first pass metabolism

(fraction of orally administered drug that successfully passes the gut wall is taken via the hepatic protal vein to the liver, where metabolism of the drug by enzymes may take place) the extraction by the liver of the orally administered drug

pharmaceutical mixture

oral liquids, usually aqueous preparations, containing one or more active ingredients dissolved or suspended in a suitable vehicle

polysaccharide can be used as a suspending agent in oral suspension and gelling agent in topical product

tragacanth

cellulose derivative can be used as a suspending agent in oral suspension and gelling agent in topical product

methylcellulose

6 excipients used in aqueous based paediatric oral suspension formulation

colouring agent / preservative / flavouring agent / antioxidants / buffers / suspending agents

distillation definition

water separated as vapour from non volatile impurities then condensed

deionisation definition

portable water passes through columns of anionic and cationic exchange resins to remove ionisable compounds

linctus

viscous oral liquids that contain one or more active ingredients in solution / vehicles contain a high proportion or sucrose, polydyric alcohol or alcohols

advantage of liquids over solids x5

easier to swallow / wide variety of dosage forms and strengths / faster therapeutic response / reduced GI irritation due to immediate dilution of gastric contents / tablets can be placed under tongue and not swallowed

stokes law definition

diffusible solid

does not dissolve in vehicle. May be mixed with vehicle so that upon shaking the powder evenly diffues throughout the liquid for sufficient time to ensure even distribution in each dose

3 organic gelling agents to prepare hydrogels

tragacanth / alginate / pectin

3 disadvantages of macrogol as base

incompatible with phenolic alcohols / brittleness and crystal growth upon storage / more irritating than fatty bases

3 reference sources used in pharmacopoeia

BP / martindale / british national formularly

5 materials used as preservatives in oral liquid formulations

benzyl alcohol / glycerol / propylene glycol / benzoic acid / sodium benzoate

3 dosage forms for rectal use

suppositories / ointments and creams / powders

3 disadvantages of glycerol-gelatin mixture as suppository base

does not melt but dissolves to cause local irritation / low melting point / hygroscopic, antimicrobial preservation might be necessary

5 materials used as suspending agents

xanthan gum, tragacanth (polysacchardies) / methylcellulose (water soluble celluloses) / bentonite (hydrated silicates) / carbomer

3 excipients incompatible with soft gelatin capsules

surfactants / glycerol / water

4 objectives of dosage form design

safety / efficiency / convenience / reproducibility

bioavailability definition

fraction of administered drug reached systemic circulation in an unchanged form

colloidal matter

particles from 0.005 to 0.02 u which tend not to sediment

2 methods of removing colloidal matter from water

reverse osmosis / coagulation

3 advantages of hypermkellose over gelatin for hard capsule shell production

less hygroscopic / meets dietary needs / less regulatory requirements due to unlikelihood fo disease

purified water for injection EUR vs purified water for injection USP

in EU and UK it must be prepared by distillation / in US it can be prepared by any method including distillation that meets the specifications

pyrogens definition

of bacterial origin and consist of lipids associated with a polysaccharide or protein or both

what do pyrogens like endotoxins cause if injected

febrile reactions

how should ph be adjusted to increase solubility of acidic drug

ph should be raised as acids ionised at high ph and will be more stable and soluble

6 advantages of liquids over solid dosage forms

easier to swallow / cannot conceal tablets under tongue / wide variety of dosage forms and strengths / faster therapeutic response / reduced irriation of GI tract / some preparations have a large bulk so liquids more feasible option

stokes law

water of crystallisation

Water chemically bonded within a crystal structure

why oral administration of injectable drug not acceptable x4

form of drug in injectable may not be orally available / slower absorption / extensive first pass metabolism so poor bioavailability and large volumes required / prohibitive cost

why certain temperature and humidity required for production of soft gelatin capsules x4

water content and affect the gelling process and plasticity / heating above 40 degrees reduces gel strength due to denaturing / excess moisture make shell harder and more brittle / make it very hygroscopic so take moisture from environment and allow microorganisms grow

reverse osmosis x3 steps

raw materials fed into permeator containing semi permeable membrane / high pressure applied to raw water exceeds osmotic pressure and reverses the direction of normal osmotic flow / water molecules forced through membrane and leave impuritied behind

type 1 glass

covalent bond between phases / reactions irreversible / not really used pharmaceutically but may be used in implants

type 2 glass

non covalent bonds between phases like hydrogen bonds