Upload
anna-graham
View
243
Download
5
Tags:
Embed Size (px)
Citation preview
Introduction Mechanisms of controlled release Intelligent controlled release DDS Examples Recent advances References
Introduction:
Fluctuating plasma level in conventional DF.
Development of CR ,SR, TR Etc.
Targeted delivery
It has goal of delivering the drug to specific cell types, tissues or organs.
Controlled release
Assigned to release the DRUG at a PREDETERMINED Rate.
Modulated release
Release of drug at a variable rate controlled by
Environmental conditions, Biofeedback, Sensor input External control device.
Sustained release (SR)
In SR –Drug release is affected by External environment.
- Release is slow than conventional DF.
In CR – Release is dependant on the
design of dosage form.
DRUG RELEASE MODULATION
ADVANTAGES
DISADVANTAGES
DRUGS UNSUITABLE FOR CR
Different controlled release systems
Time of release
Cumulativerelease
Burst like release
Pulsatile release
Diffusion controlled release
Zero order (linear) release
Lag followed byBurst release
FACTORS GOVERNING THE
DESIGN OF CR DOSAGE FORMS
I. Drug related II. Biological III. Physiological IV. Pharmacokinetic V. Pharmacological
FACTORS GOVERNING THE DESIGN OF CR DOSAGE FORMS
aqueous solubility
protein bindingdrug stability
molecular size
partition coefficient
Drug relatedDrug related
FACTORS GOVERNING THE DESIGN OF CR DOSAGE FORMS
absorption
side effects
margin of safety
elimination
distribution
duration of action
disease state Biological
FACTORS GOVERNING THE DESIGN OF CR DOSAGE FORMS
Physiological
prolonged drug absorption
GI blood flow
variability on GI emptying & motility
FACTORS GOVERNING THE DESIGN OF CR DOSAGE FORMS
Pharmacokinetic
first pass metabolism
variability of urinary pH effect on drug elimination
dose dumping
FACTORS GOVERNING THE DESIGN OF CR DOSAGE FORMS
Pharmacological
changes in drug effect upon multiple dosing
Sensitivity / tolerance
BASIC PRINCIPLES OF CR
DIFFUSION
SWELLING
BIODEGRADABLE or BIOERODIBLE
Schematic depiction of various classes of controlled release system
Controlledrelease system Water penetration controlled
Swelling
Chemically controlled
Erodible
Hydrogel
DiffusionSwellingEnvironmental
Ion exchange resin
anioncation
Chemically
Diffusion
Reservoir and monolithic
Matrix
ReservoirDissolution
Encapsulation Matrix
Diffusion and Dissolution
osmotically
Drug linked polymer
DIFFUSION CONTROLLED SYSTEMS
MONOLITHIC-MATRIX SYSTEMS
Drug +
polymer
MONOLITHIC-MATRIX SYSTEMS Materials used as retardants in matrix tablet formulations :-MATRIX
CHARACTERISTICSMATERIAL
Insoluble, inert matrix
PolyethylenePolyvinyl chlorideEthylcellulose
Insoluble, erodable
Carnauba wax
Polyethylene glycol
Castor wax
hydrophilic
Methyl cellulose
Carboxypolymethylene
Sodium alginateHPMC
Oral system
RESERVOIR SYSTEMSRESERVOIR SYSTEMS
RESERVOIR SYSTEMS
First layer Of the drugcrystals
Polymer phase
Diffusion layer
DIFFUSION CONTROLLED SYSTEMS
Reservoir system
Achievement of zero order is easy
Degradable reservoir systems may be difficult to design
Rupture can result in dangerous dose dumping
Drug inactivation by contact with the polymeric matrix can be avoided
Matrix system
o Achievement of zero order is difficult
Suitable for both degradable & non-degradable systems
No danger of dose dumping
Not all drugs can be blended with a given polymeric matrix
Phase I – outer membrane layers
Phase II – reservoir matrix material
COMBINED RESERVOIR-MONOLITHIC SYSTEMS
Outer membrane layer (phase I)
Dispersed agent in polymer matrix(phase II)
COMBINED RESERVOIR-MONOLITHIC SYSTEMS
MonolithicMatrix (phase II)
Outer membrane(phase I)
Agent loadedMatrix layer
Agent depletedMatrix layer
Initially the release rate of diffusion through the phase 1 ,as the time progress ,a layer depleted from the active agent is generated in phase 11 reservoir material immediately adjacent to the membrane layer.
DISSOLUTION CONTROLLED RELEASE SYSTEMS
Two classes:Encapsulation dissolution control
Matrix dissolution control
Matrix Matrix dissolution controldissolution control
Membrane controlledMembrane controlled Polymer erosion controlledPolymer erosion controlled
drugdrug
membranemembrane
DIFFUSION & DISSOLUTION DIFFUSION & DISSOLUTION CONTROLLED SYSTEMSCONTROLLED SYSTEMS
Release rate is dependent on surface area diffusion coefficient
of drug though pore in coating
conc. of drug in dissolution media.
membrane
drug
WATER PENETRATION CONTROLLED SYSTEMS
rate control is obtained by penetration of water into the system.
classified into 2 parts.swelling controlled systems
osmotically controlled systems
SWELLING CONTROLLED SYSTEM
solvent
Swollen matrix Swelling zone
Unswollen polymer matrix
“Non-fickian case II” type diffusion
CHEMICALLY CONTROLLED SYSTEMS
delivery systems that change their chemical structure , when exposed to biological milieu
This system include biodegradable polymer that degrade within body as a result of natural biological process ,eliminating the need to remove the delivery system after exhausting of active agent from system
CHEMICALLY CONTROLLED SYSTEMS
The polymer degradation by 2 ways:
Bulk erosion surface erosion
MECHANISM OF POLYMER EROSION
Type IA – cleavage of cross links
Type IB – disintegration of water soluble polymer backbone
MECHANISM OF POLYMER EROSION
Type II – Water insoluble macromolecules are converted into water soluble compounds by hydrolysis, ionization or protonation of a pendent group.
hydrolysisIonizationprotonation
Water insoluble molecules Water soluble molecules
MECHANISM OF POLYMER EROSION
Type III – erosion mechanisim
Water insoluble molecules Water soluble molecules
Hydrolytic
cleavage
MECHANISM OF DRUG RELEASE
bioactive covalently linked to polymer backbone , scission of the bonds connecting the drug to polymer backbone.
List of biodegradable polymer
Polylactides (PLA). Polyglycolides (PGA).
Poly(lactide-co-glycolides) (PLGA).
Polyanhydrides. Polyorthoesters.
HYDROGELS
–Hydrogels are water swollen three dimensional structures composed of primarily hydrophilic polymers.
HYDROGELS
Classification:-1) Diffusion controlled release
- reservoir- matrix
2) Chemically controlled release - biodegradable polymers- covalently linked drug & polymer
3) Swelling controlled release4) Environmentally responsive hydrogel systems
Swelling controlled release consists of drug dispersion within glassy
polymer matrix. When the system comes in contact with biofluids, it starts swelling.
Drug releaseGlassypolymer
Swollen gel
water
HYDROGELS
Environmentally responsive hydrogel systems
The changes in network structure in response to external environment are reversible in nature.
T
pH pH
T-
-
Type of hydrogel Type of hydrogel
Super porous hydrogel pH sensitive hydrogel Temperature sensitive hydrogel Glucose sensitive system Neutral hydrogel Oral insulin hydrogel
Super porous hydrogelSuper porous hydrogel
Mainly for speedy swelling
Carried out by making very fine particle of dried hydrogel having short diffusion path length
Electronic microscopic fig of super porous hydrogel
Recent application of super Recent application of super porous gel in drug deliveryporous gel in drug delivery
DEVELOPMENT OF GASTRIC
RETENTION DEVICES
Development of fast dissolving tablet
Development per oral peptide delivery system
ION-EXCHANGE RESINION-EXCHANGE RESIN Zero order release obtained
kinetics Drug release depends only on the ionic environment of the resins containing drug
2 types.- cation exchange resin & anion exchange resin.
CATION EXCHANGE CATION EXCHANGE RESIN :-RESIN :-
Synthesized by copolymerization of divinyl benzene & styrene.
CH
CH
CH2
CH2
CH CH2
divinyl benzene
styrene
CH
SO3H
CH2 CH CH2
CH
CH
SO3H
CH2 CH2CH CH2
CH
CH
SO3H
CH2
CH
SO3H
CH2 CH
CH
CH2CH2CH2CH CHCH
SO3H CHCH
Anion exchange resinAnion exchange resin is prepared by
chloromethylation of benzene rings of three dimensional styrene-divinyl benzene copolymer network leading to insertion of –CH2Cl groups & forms strong anion exchange resin.
CH
Cl- (CH3)3N+CH2
CH2 CH CH2
CH
CH2 CH2CH CH2
CH
CH2
CH2 CH
CH
CH2CH2CH2CH CH
CHCH
CH2N+(CH3)3Cl-
CH
CH2N+(CH3)3Cl-
CH
CH2N+(CH3)3Cl-
CH
CH2N+(CH3)3Cl-
CH
INTELLIGENT CONTROLLED RELEASE DRUG DELIVERY SYSTEMS:-
Provide the bioactive in response to the physiological need & should ‘sense’ the changes & manipulate the drug release in response to external stimuli like heat, ultrasound, magnetic field, pH and/or conc. of specific molecules.
:-
CLASSIFICATION:CLASSIFICATION:
pulsatile systems responsive systems
systems utilizing chelation
systems utilizing enzymes
systems utilizing antibodies
INTELLIGENT CONTROLLED
RELEASE SYSTEMS
electically regulated ultrasonically modulated
magnetically modulated
photoresponsive
Glucose sensitive
inflammation responsive
thermosensitive
pH sensitive
urea responsive
glucose responsive
PULSATILE SYSTEMS :-
Magnetically modulated systems :-
No applied field
Field turn on Drug release
RESPONSIVE SYSTEMSRESPONSIVE SYSTEMS Glucose sensitive polymers :-
Glucose in Glycosylated insulin out
Polymer membrane
Glycosylated insulin
glucose
Concavalin A
Sepharose 4B beads
Glucose sensitive polymers :-
insulin
microcapsule
Polymer A Polymer B
release
glucose
RESPONSIVE SYSTEMSRESPONSIVE SYSTEMS
SYSTEMS UTILIZING ENZYMES
a) Urea responsive delivery systems Urea is converted into NH4HCO3 & NH4OH by the action of urease that increases the pH.
Hydrogel prepared by immobilizing urease In cross-linked bovine serum albumin
N-hyxyl half ester with dispersed drug
SYSTEMS UTILIZING ENZYMES b) Glucose responsive insulin
delivery :-This system utilizes enzyme-
glucose oxidase which converts glucose into gluconic acid.
Glucose + O2 gluconic acid + H2O
G
G
G
G
HNR2
HNR2
HNR2
HNR2
HNR2
HNR2
GluOx
G
NR2
NR2
NR2
NR2
NR2
NR2
GluOx
GluOx
G NR2
NR2
NR2
NR2
NR2
NR2
GluOx
GluOx
G
G
G
SYSTEMS UTILIZING ENZYMES
b) Glucose responsive insulin delivery :-
GOD GOD
HOOC COOH
insulin
GOD GOD
-OOC COO-
insulin
glucose
insulin
An insulin reservoir (like a regular syringe)
A small battery operated pump
A computer chip for control
Combination with Glucose sensors
Examples:
Insulin pump,Gluco
watch
Recent information
Polymer therapeuticscovers natural or synthetic polymers,
which have either inherent therapeutic potential or carry covalently bonded drugs. The covalently bonded drugs have to be released at the desired tissue or cell type. Polymeric therapeutics aree.g. polymeric drugs, polymer-protein conjugates, polymer-DNA complexes, polymer-drug conjugates or polymeric micelles.
Chemo mechanical polymer Chemo mechanical polymer drug delivery systemdrug delivery system
Chemomechanical polymers, developed by Professor Hans-Jorg Schneider and his team at the University of Saarland, Germany, have greatly improved functionality compared to existing expanding / contracting materials used to perform biomedical functions, and could be used in applications such as actuators, implants, drug release systems and drug screening.
New polymer enables near zero order drug release
Cavilink TMd
Highly porous polymer micro bead
Advance technologies in modified release from dosage form
TIMERx MASRx & COSRx systems
Procise (comprised of a compression coated core) Drug Delivery Systems Based on Geometric Configuration
Ringcap Technology – tablets
Advance technologies in modified release from dosage form
Smartrix system – multiple layered tab. Novel Erosion-Controlled Oral Delivery SystemTheriform Technology – novel method of fabrication based on three dimensional printing, a solid freeform fabrication technology- implantsAccudep technology – layered capsules
Advance technologies in modified release from dosage form
Threeform technology ,- Meltrex technology – melt extrusion process
Dissocubes –,IDD technology – insoluble drug delivery technology
Zydis oral fast dissolving dosage form. Orasolv & Durasolv – efficient
technologies for production of orally disintegrating tablets.
References:-
S.P.Vyas, R.K.Khar, Controlled drug delivery- concepts & advances., 1-50, 167
G.S.Banker, Modern Pharmaceutics, 3rd edition, 575 Chien Y.W., Novel fundamentals, developmental
concepts, biomedical assessments. Robinson & Lee, controlled drug delivery:
fundamentals and applications, 2nd edition. Donald L.Wise, Handbook of Pharmaceutical
controlled release technology, 443. Praveen Tyle , drug delivery devices: fundamentals
and applications, Marcel Dekker, 326-363, 376-382. James Swarbrick, James C. Boylan, Encyclopedia of
Pharmaceutical Technology, Marcel Dekker, III, 282, 297-311.
References:-
Remington: The Science and Practice of Pharmacy, 19th edition, 1660-1675
Leon Lachman, The Theory and Practice of Industrial Pharmacy, third edition, 453.
www.minimed.com www.glucowatch.com Talukdar M. M. , Kinget R., Swelling and drug
release behaviour of xanthan gum matrix tablets, Int. J. Pharm. 120 (1995) 63–72.
Al-Shamkhani A. and Duncan R. Int. J. Pharm. 122(1995) , 107.
Brown L., Edelman E., Fishel Ghodsian F. and Langer R. J.Pharm.Sci. 85 (1996), 1341.
References:-
Giannos S., Dinh S. and Berner B. J. Pharm. Sci. 84 (1995), 539.
Heller J. and Trescony P.V. J. Pharm. Sci. 68 (1979), 919.
Hoes C. J. Control. Rel. 38(1996),245. Kabanov A. and Alakhov V. J. Control. Rel. 28 (1994),
15. Kallstrand G. and Ekman B. J. Pharm. Sci. 68
(1976),325. Theeuwes F. and Bayne W. J. Pharm. Sci. 66 (1977),
1388. Yokayama M, Okano T., Sakurai Y. and Kataoka K.
J.Control. Rel. 32 (1994), 269. Michael J. Rathbone., Modified Release Drug Delivery
Technology, volume 126, Marcel Dekker., Pages 1, 216.
References:-
Joseph R. Robinson, Sustained release and controlled release drug delivery systems, volume 6,Marcel Dekker.
R.E. Notari, J. Pharm. Sci.,62, 865 (1973) G.L.Flynn, S.H. Yalkowsky and T.J. Roseman, J.
Pharm. Sci.,63, 479 (1974) S.Motycka and J.G.Naira, J. Pharm. Sci., 67, 500
(1978)
References:-
Theeuwes F. Elementary osmotic pump. J Pharm Sci. 1975;64:1987-1991.
Zentner GM, Rork GS, Himmelstein KJ. The controlled porosity osmotic pump. J Controlled Rel. 1985;1:269-282.
Swanson DR, Barclay BB, Wong PS, Theeuwes F. Nifedipine gastrointestinal therapeutic systems. Am J Med. 1987;83(suppl 6B):3-9.
Carrigan PJ, Bates TR. Biopharmaceutics of drug administered in lipid- containing dosage forms, part I: GI absorption of griseofulvin from an oil-in-water emulsion in the rat. J Pharm Sci. 1973;62:1477.
Noguchi T, Takahashi C, Kimura T, Muranishi S, Sezaki H. Mechanism of the intestinal absorption of drugs from oil-in-water emulsions. Chem Pharm Bull. 1975;23:775. 6. Constantinides PP. Lipid microemulsions for improving drug dissolution and oral absorption: physical and biopharmaceutical aspects. Pharm Res. 1995;12:156.
References:-Wichterle O, Lim, D. Hydrophilic gels for biological use. Nature. 1960;185:117-118. Chen J, Blevins WE, Park H, Park K. Gastric retention properties of superporous hydrogel composites. J Controlled Rel. 2000;64:39-51. Shalaby WSW, Blevins WE, Park K. In vitro and in vivo studies of enzyme-digestible hydrogels for oral drug delivery. J Controlled Rel. 1992;19:131-144. Shalaby WSW, Blevins WE, Park K. The use of ultrasound imaging and fluoroscopic imaging to study gastric retention of enzyme-digestible hydrogels. Biomaterials. 1992;13:289-296. Drews J. Quest of Tomorrow's Medicines. New York, NY: Springer-Verlag; New York; 1999. Dorkoosh FA, Borchard G, Rafiee-Tehrani M, Verhoef JC, Junginger HE. Evaluation of superporous hydrogel (SPH) and SPH composite in porcine intestine ex-vivo: assessment of drug transport, morphology effect, and mechanical fixation to intestinal wall. Eur J Pharm Biopharm. 2002;53:161-166.
References:- Dorkoosh FA, Verhoef JC, Borchard G, Rafiee-Tehrani M, Junginger
HE. Development and characterization of a novel peroral peptide drug delivery system. J Controlled Rel. 2001;71:307-318.
Dorkoosh FA, Verhoef JC, Ambragts MHC, Rafiee-Tehrani M, Borchard G, Junginger HE. Peroral delivery systems based on superporous hydrogel polymers: release characteristics for the peptide drugs buserelin, octreotide, and insulin. Pharm Sci. (In press).
Dorkoosh FA, Verhoef JC, Verheijden JHM, Rafiee-Tehrani M, Borchard G, Junginger HE. Peroral absorption of octreotide in pigs formulated in delivery systems based on superporous hydrogel polymers. Pharm Res. (in press).
Chang R-K, Guo X, Burnside BA, Couch RA. Fast-dissolving tablet. Pharm Technol. 2000;24(6):52-58.
Kallmes DF, Fujiwara NH, Max WF. Angiographic and histologic evaluation of an expandable hydrogel material for aneurysm embolization. Paper 107 presented at the 37th Annual meeting of the American Society of Neuroradiology, April 2-8, 2002; Dallas.
Ciceri EF, Dickerson J, Klueznik RP, Moret J, Mawad ME. Embolization of experimental porcine aneurysms with a combination platinum coils and hydrogel material. Paper 106 presented at 37th Annual Meeting of the American Society of Neuroradiology, April 2-8, 2002; Dallas.