Solution Dosage Forms Flashcards
Drugs in solution dosage forms
Solute. Small molecular or larger peptides and proteins
Solvents in solution dosage forms
Excipient that solute dissolves in. Polarity and toxicity are important considerations. Cosolvents may be necessary
Use of excipients in solutions
Increase solubility, pH buffering, maintains stability (physical, chemical and microbiological), better absorption, colouring and flavour enhancement
What patients have an insufficient swallow reflex for tablets
Children under 12 (undeveloped) and older persons (muscle atrophy)
Solutions advantages over tablets
Easier swallowing, rapid absorption (doesn’t need to be liberated), flexible dose adjustment (homogenous solution = uniform drug conc in solution), no need to shake dosage form (better then suspension) and lower chance of GI irritation
How tablets cause GI irritation
Tablets in stomach are concentrated at 1 point on wall. Large concentration of drug enters and gets trapped into samll group of gastric cells, killing them
Solution Disadvantages
Bulky (hard to transport and store), more frequent dosing (due to rate of absorption), more susceptible to chemical degradation and microbe contamination, poor taste
What makes solutions more sensitive to chemical degradation
Drugs in water can be subject to neutrophilic/electrophilic attack by water and degradation due to oxidation in water
Aromatic Oil Outline
Oil (hydrophobic) is shaken in water. A tiny (negligible) fragment of oil dissolves in water (no cosolvent). Don’t tend to have therapeutic effects (exception peppermint and flatulence).
Concentrated Water Outline
Higher concentration of oil in water (due to cosolvent) then in aromatic waters
Concentrated Oil Outline
Higher oil content then water
Spirit Outline
Solution where an alcohol is the main solvent (sometimes with water) and a volite substance
Elixir Def
Oral solutions with alcohol as a cosolvent. Unsuitable for children as they don’t have alcohol metabolism (results in hyperglycemia). Alcohol doubles as a perservative. Eg paracetamol
Syrup Outline
Oral aqueous solution contains high concentrations of sucrose or other sugars (more sugary if plant based). Sugar acts as a preservative (bacteriostatic). Acts as a demulcent (coating on throat prevents gas irritation)
How syrups are susceptible to bacterial infections
Due to an intense heat change over a short amount of time. Condensation builds in bottles forming a layer of water (low in sugar on top). This layer can be easily infected
Invert Syrup Outline
Breaks down sucrose into fructose and glucose. Different polarity and sweetness then other syrup
Syrup Disadvantages
Sugar conc impacts other excipient solubility, susceptible to surface dilution, tooth decay and not accessible for diabetics
Cap locking Outline
Screw on caps for syrups. When syrup spills on lid, it recrystalises making it hard to turn cap. Sorbitol, glycerol and other polyhdric alcohols can be excipients in syrups to reduce recrystalisation in syrups not For children
Expectorate Outline
Coughing stimulant
Linctus Outline
Viscous oral liquid. Due to it’s slow movement it properly coats the throat (demulcent)
Mixture Def
Solution/suspensions with 2 or more active ingredients dissolved, suspended or dispersed in a suitable vehicle
Mouthwashes Outline
Dosage form used to cleanse oral cavity. Don’t swallow
Gargles Outline
Aqueous solution containing antiseptics, antibiotics and anesthetics. Used to treat the pharynx, by forcing air from lungs
Oral Drops Outline
Oral solutions/suspensions administered with small volume with a metered device
Oral Solution Outline
Local and systemic effects. Administered in 5ml doses (spoon, syringe and cup). Contained in amber bottles (prevent catalytic oxidation due to light) with child proof locks. Greater viscosity then water. Average pH is 7 (range 2-9)
Parenteral Outline
Sterile, pyrogen free. pH to be similar to site of admin to prevent precipitation (phlebitis). Perservatives are used in a multidose. Aqueous and isotonic
Lotions Outline
Solutions/suspensions for external topical application without friction
Liniment Outline
Solution rubbed deep into skin to repair damage muscles
Paints and tinctures
Antimicrobrial solution that’s only applied to specific regions of skin (eg infected ones) as it damages other cells
Collodion Def
Solution of a plolmer with an organic volatile solvent (eg alcohol) for topical applications
Transungual Def
Solutions applied to nails to soften them to treat fungal infections
Chemical instability when drugs are dissolved in water
Drugs undergo specific base hydrolysis when reacting by nucleophilic substitution with water. This new form of the drug will not be therapeutically active and can range from being inert to cytotoxic
How drugs may experience hydrolysis when not dissolved in water
In humid environments drugs can absorb water from environment causing degradation
Relationship between pH and hydrolysis
more extreme pH = more ionised substance = more soluble = more unstable = greater hydrolysis
Good Manufacturing Practice Outline
Test of quality, purity, stability, safety and efficacy. Regulated by regulatory agencies eg HPRA. Is an expensive, time consuming but necessary process
Compounding Outline
Manipulating the properties of a licensed product to use it for circumstances it was not designed specifically for. High risk (only documentation is from people who’ve compounded before and their specififc results)
Off license Treatment outline
Using a drug/dosage form for treatment or administration that it wasn’t intended for (no tests were preformed)
2 types of packaging for internal solutions
Flat amber medical bottles and round amber medical bottle with dropper (labels put on flat side, round side used for spill run off
Packaging for external solutions
Fluted (1 round side and 1 flat) amber bottle
Organoleptic Properties Def
Sensory perceptions of substances
Examples of taste masking
Administering as suspension instead of solutions (suspension particles are too big to bind to taste receptors), matching color with taste (eg pink and strawberry) , flavoring excipients (eg acididc with citrus tastes)
Psycorheology Outline
The sensory feel of a dosage form eg high viscosity is not palatable (high viscosity = longer shelf life, shaking can thin out substance before admin)
Pediatric Solutions
Children on average can only swallow tablets at the age of 12. Children are dosed with solutions by weight, treated like smaller adults. Have to be careful with cosolvents (no alcohol)
Example of safe cosolvent
propylene glycol
Example of unsafe cosolvents
diethylene glycol and methylene glycol
Expiration Date Outline
Formal evaluation of shelf life based on rigorous testing. When 10% of therapeutic activity is lost it is expired (even less if drug is cytotoxic). Ideal is 3-4 years
Beyond Use Dates Outline
Informal evaluation of shelf life which is an estimate without data. Used for compounded products
Aqueous Dosage Form Expiration Dates Outline
Have shorter shelf lives. Water is prone to microorganism infection. Topical can include antimicrobrilas but oral can’t
Cold Storage Temp Outline
< 8 degrees Celcius
Refridgerated Storage Temp Outline
+2 to +8 degrees Celcius
Freezer Storage Temp Outline
-10 to -20 degrees Celcius
Cool Outline
8 to 15 degrees Celcius
room temp outline
20 to 25 degrees Celcius
