Most of the materials used in swelling-controlled release systems are based on
hydrogels
, which are polymers that will swell without dissolving when placed in water or other biological fluids. These hydrogels can absorb a great deal of fluid and, at equilibrium, typically comprise 60–90% fluid and only 10–30% polymer.
Which polymer is used in drug delivery?
Among the synthetic and biodegradable polymers, aliphatic polyesters such as
poly (glycolic acid), poly (lactic acid), poly (caprolactone)
and polydioxanone, are most commonly used and applied to drug delivery systems.
What is used in controlled drug release?
A combination of nanospheres and nanocapsules
is also used for drug release control. Docetaxel (DTX) was loaded in a PLGA NP, surrounded by PEGylated lipids (Chan et al., 2009). DTX release was extended as the lipid/polymer mass ratio increased. Here, the lipid monolayer acted as a barrier for drug diffusion.
How can polymers be used as controlled release devices?
To control the drug release rate from the formulation, polymers are
being used as the main tool
. Polymers can be used as taste masking agents, to enhance stability of drug and to modify drug release characteristics. Biodegradable materials are used in medicine and other areas.
How do polymers release drugs?
For polymeric materials the mechanisms of drug release are normally
directly linked to drug diffusion, dissolution, and degradation of the carrier matrix
. However, other factors, such as interactions of the material and the drug, can also influence the release kinetics.
Which of the following is hydrophilic polymer used for drug delivery?
Hydrogels
are often used for the delivery of hydrophilic drugs. However, as the polymer matrix is hydrophilic, hydrophobic drugs are generally incompatible with hydrogels [9].
Which polymer is used in mucoadhesive drug delivery system?
The various mucoadhesive polymers which have been used for the development of oral delivery systems include
chitosan, poly(acrylic acid), alginate, poly(methacrylic acid)
and sodium carboxymethyl cel- lulose [62].
What is difference between sustained release and controlled release?
Sustained release dosage forms are designed to release a drug at a predetermined rate in order to maintain a constant drug concentration for a specific period of time with minimum side effects. … Whereas controlled release systems offer
prolonged release
at a specific controllable rate.
How is the importance of drug controlled release in biomedical applications?
Controlled release DDS are
able to improve the bioavailability of the drug by preventing its premature degradation
, maintaining its concentration within therapeutic range, reducing concentration fluctuations and ultimately reducing the potential side-effects.
What are controlled release formulations?
Controlled-release (CR) formulations have been introduced into drug therapy with two main purposes: to
reduce the number of single doses per day improving patient compliance of treatments
and to decrease the fluctuations of plasma levels, in order to obtain better therapeutic efficacy and lower toxicity.
What are the two categories of polymers?
- thermosetting plastic or thermoset.
- thermoforming plastic or thermoplastic.
Which is bio responsive implant?
2
Bioresponsive Hydrogel
. The term bioresponsive means to generate a biological response upon stimulation by the surrounding environment. The bioresponsive hydrogels are designed to have a conversation with surrounding biological environment and respond according to its stimulus.
What is polymer membrane permeation controlled drug delivery?
A membrane permeation-controlled transdermal delivery system (MC-TDS) of
isosorbide dinitrate (ISDN)
, a model drug, was prepared from polyvinyl alcohol aqueous gel containing the drug, a membrane consisting of ethylene-vinyl acetate copolymer membrane and acrylic adhesive (EV-a).
How polymers are used in drug delivery system?
Polymers have played an integral role in the advancement of drug delivery technology by providing
controlled release of therapeutic agents in constant doses over long periods
, cyclic dosage, and tunable release of both hydrophilic and hydrophobic drugs.
Which one is not polymer?
If the forming units of the given biological macromolecules are considered, proteins are formed of amino acids joined one after the other, polysaccharides are formed from monosaccharides, nucleic acids are formed of nucleotides. Only
lipids
are not made of uniform components, that is, they are not polymeric.
What are polymers in pharmacy?
Pharmaceutical polymers include
vinyl polymers, cellulose ethers, polyesters, silicones, polysaccharides and other biopolymers
.
