Lecture 16- Biopharmaceutics III Flashcards
Enhancing dissolution- lipid based formulations
Consists of drug dissolved in veg oil/triglycerides
High lipophilicity= facilitates drug absorption
Prescence of surfactant= enhanced absorption due to membrane induced permeation changes
Surfactants= stabilize the emulsion + protect droplets against aggregation
Co-solvents= increase the solubilization of incorporated drugs
Enhancing dissolution- size reduction technology
Surface area increases by decreasing particle size which results in higher dissolution rate
Reduction in particle size= accompanied by micronization - milling (impact and attrition), grinding + superficial fluid technology
Enhancing dissolution- functional polymer technology
Enhances the dissolution rate of poorly soluble drugs by avoiding the lattice energy of the drug
Fresh polymers are for exchange materials that interact with the ionizable molecules of the surrounding medium + exchange their mobile ions of equal charge with surrounding medium reversibly e.g. amber lite, duolite
Resultant complex; resinate= formulated as suspension, dry powder/tablet e.g codeine/ chlorpheniramine dual drug deliver
Enhancing dissolution- porous microparticle technology
Core technology applied as HDDS; hydrophobic drug delivery system - provide a larger surface area for increased dissolution rate
Slide 6
Enhancing dissolution- hydrophilic solubilization
For poorly soluble drugs- uses a lecithin + gelatin-based water-soluble drug coating to improve dissolution + hydration
Coating forms= micelles which improve oral bioavailability of the insoluble drugs
Enhancing dissolution- controlled precipitation
Drug is dissolved in a water-miscible organic solvent + then dispersed into aqueous medium containing stabilisers
Solvent- dissolves in water and causes precipitation of the drug in the form of micro-crystals
Stabilizers= control particle growth + enhances the dissolution rate of poorly soluble drug due to large surface area, hydrophilized by the adsorbed stabilizer
Enhancing dissolution - inclusion complexes
Prepared with B-cyclodextrin + HP-B-CD; cyclic oliogosaccharide
Outer surface= hydrophilic
Inner surface= hydrophobic
Required quantity of B-CD is weighed + water added for consistency
Method- slide 11
Enhancing dissolution- solid dispersions
Dispersion of one/more active ingredients in an inert carrier/matrix at solid state prepared by the fusion, solvent/melting solvent method
Carriers;
Sugars- dextrose, sorbitol, mannitol
Acids- citric, tartaric + succinic acid
Polymeric materials- PEG 4000, PEG 6000, HPMC
Enhancing dissolution- solid dispersions
Fusion method; slide 14
Drug + carrier melted -> cooling/solidification -> crushed + sieved
Solvent evaporation method - slide 15
Drug + solid components -> dissolved in solvent -> solvent evaporated
Melting-solvent method- slide 16
Drug dissolved in solvent -> solution mixed with carrier melt
Enhancing dissolution- eutectics
Slide 17
