solution dosage forms

constituents of drug

can be conventional small molecular or larger peptides or proteins

solvent constituents

water alone does not dissolve many drug compounds to a sufficient degree to form a solution

excipients constituents

key functions in solution dosage forms include improving solubility, improved absorption, stability, buffering, coloring, flavor enhancement, optimism of use conditions

solution dosage form advantages

• easier to swallow than tablets or capsules

• readily absorbed in the GIT, rapid onset

• easy to administer to children

solution dosage form disadvantages

• bulky

• rapid onset can result in more frequent dosing

• taste

• more sensitive to chemical degradation

aromatic water

saturated aqueous solutions of volatile oils or other aromatic or volatile substances

spirits

alcoholic or hydroalcoholic solution (60%+) of volatile substance

elixir

oral solutions that contain alcohol as a cosolvent

clear, fluidic solutions where active is solubilized by cosolvent with alcohols

self preserving over 155

significant safety concerns regarding children

paracetamol, diazepam

syrups

oral aqueous solutions containing high concentrations of sucrose or other sugars

66% sucrose in purified water

syrups problems

very high sugar conc. can influence the solubility of other constituents of the dosage form

susceptible to surface dilution

tooth decay

not suitable for diabetics

cap-locking in solutions

involves recrystallisation in the cap threads at the bottle cap interface and makes opening the cap difficult after prolonged periods of non-use

common is syrups

linctus

viscous oral liquids that may contain one or more active ingredient in the solution. high sucrose and alcohol. relief of cough

mixture

solutions or suspensions containing one or more active ingredients dissolved, suspended or dispersed in a suitable vehicle

mouthwashes

typically aqueous solutions containing antiseptics, antibiotics, anesthetics used to treat pharynx

oral drops

oral solutions which are administered in small volumes using a suitable measuring device

oral solution

• both local and systemic

• commonly 5ml

• spoon, cup, syringe

• reclosable amber bottles

• palatable and visually appealing

• pH is 7

  • more viscous than water

parenteral solution

• injectable route, must be sterile

• pH 3-9

• preservatives used in multidose

• IV are aqueous

• IM or SC can be aqueous or non-aqueous

• large volumes

topical solution

• both local and systemic

• can be viscous but not tacky

• vehicle can be aqueous or non-aqueous

• commonly used in parasiticides and antimicrobials

  • lotions, liniments, paints, collodion, ungual and trans ungual solutions

otic solutions

• solution instilled to remove wax

• may be aqueous or non-aqueous

• residence time enhanced with viscosity enhancing polymers

  • no requirement for insotonicity

ocular solutions

• treatment of local and selected intraocular disorders

• commonly aqueous

• eye lotions are solutions for rinsing

• multidose preparations require preservation

• pH must be carefully balanced

  • viscosity is important in residence time

hydrolysis

the acetyl ester in aspirin is hydrolyzed to acetic acid and salicylic acid in the presence of moisture, but in a dry environment the hydrolysis of aspirin in negligible

manufacturing solutions

the manufacturing process for preparations for oral use should meet the requirements of good manufacturing process GMP e.g. quality of materials, uniformity of mass and dose, pH

why extemporaneously compound solutions

no commercially available formulation

pediatrics, geriatric

liquids are used to avoid non-compliance

permits enteral feeding

improved control over dose

organoleptic properties

the drug must be palatable (sweet, sour, bitter)

taste of the drug must match specific flavours to ensure masking

psychorheology

study of the psychological and sensory characteristics of a material as a result of its rheological properties

solutions in pediatrics

pharmaceutical manufacturers dilute medicines by first dissolving or suspending drug particles in vehicle and administered in a convenient dosage form