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Pharmaceutics …CONTENTS: CONTENTS Introduction Different eye aliments & drug therapy Anatomy and physiology of the eye Mechanism of Ocular Absorption Factors affecting ocular drug absorption Pharmacokinetics of ocular drug delivery system Approaches in Ophthalmic Drug Delivery System ICH Guidelines for ocular drug delivery system Future considerations for ocular drug delivery system Case study Conclusion References 2Ocular drug delivery system (ODDS): Ocular drug delivery system (ODDS) 3 Introduction Objectives of ODDS 1. In the treatment of local and systemic ophthalmic diseases 2. To design a therapeutic system to achieve an optimal drug concentration at the active site for the appropriate duration . 3. To correlate and understand the basic physiochemical properties of drug and relevant anatomy & physiology of eye 4. To understand major drawbacks of conventional drug therapy successfuly designing ODDS in terms of safety, efficacy and patient compliance Two major approaches for ODDS. To prolong the contact time of drug with corneal surface To enhance corneal permeability either by mild structural alteration of corneal epithelium or by modification of chemical structure of the drug molecules.PowerPoint Presentation: 4 1. Refractive Errors – most frequent eye problems a.Myopia b. Hypermetropia Corrected by eye glasses, contact lenses or by surgery 2. Macular diseases Age related Macular Degeneration (AMD) Affects macula , damaging of sharp & central vision 3. Diabetic retinopathy (DR) - common complication of diabetes. 4. Glaucoma – Ocular hypertension (press = 22 mm of Hg) leds to infarction of nerve fiber bundles. 5. Amblyopia – “Lazy – eye” - imbalance in position of the two eyes (absence of depth perception)— vision impairment in children Different eye ailments & drug therapy: 5 Drug therapy 1. Agents for treatment of Glaucoma - A Parasympathomimetics :- drugs that mimic Acetyl choline effect as Miotics – e.g. Pilocarpine HCl – increases the outflow of aqueous humor B. Sympathomimetics -- β blockers as adrenaline – changes the dynamics of aqueous humor – increases the clearance and outflow. C. Adrenargic antagonist– decreases secretion of aqueous humor . 2. Mydriatics – dialate the pupil. e.g. atropine 3. Cycloplegics – leads to paralysis of accomodation e.g. atropine 4. Anti microbials and Anti-inflammatory agents – infections due to virus and bacteria diseases such as conjutivities , keratitis . 5.Steroids as corticosteroids and NSAIDS – e.g. Bromfenac .Anatomy & Physiology of eye: Anatomy & Physiology of eye 6 Structure of an eye – 1) Anterior Segment – 1/3 of front eye - Cornea, Iris ,ciliary body, aqueous humor & lens 2) Posterior Segment – 2/3 of back of eye – Sclera , choroid, retina, macula, optic nerve & vitreous humorGENERAL PATHWAY FOR OCULAR ABSORPTION: GENERAL PATHWAY FOR OCULAR ABSORPTION 7Mechanism Of Ocular Absorption: Mechanism Of Ocular AbsorptionFactors Affecting Drug Absorption : Factors Affecting Drug Absorption A. corneal constraints /barrier 1) precorneal barriers/ loss factors 2) corneal barriers. B. physicochemical properties of drugs C. Tight junctions of super facial conjunctival epithelium A. corneal constraints 1) precorneal barriers/ loss factors Drug elimination by precorneal lacrymal fluid is by 1) solution drainage 2) Lacrimation (0.66 μ l /min) 3) dilution of drug by tear turnover 4) enzymatic metabolism 5) Naso-lacrimal drainage ---systemic drug absorpt ion ( 75% loss of the drug) follows first order rate kinetics 9PowerPoint Presentation: 2) Corneal barrier –Epithelium, Stroma & endothelium affects drug absorption. Epithelium - facing tears with lipophilic layer -barrier to ion transport . Tight junctions of corneal epithelium -selective barrier of large size molecules Stroma - highly hydrophilic- constitute 90% of the cornea- allows hydrophillic drug molecules. Corneal endothelium - maintaining normal corneal hydration – very sensitive to surfactants and antimicrobial preservatives . Physicochemical drug properties – lipophilicity, solubility, molecular size, shape, charge and degree of ionization affects the route and rate of permeation through corneal membrane in the cul-de-sac Hydrophilic drugs - paracellular pathway -- passive and altered diffusion through intra cellular spaces . 2) Lipophilic drugs- --- trans cellular pathway . Tight junctions of the superfacial conjunctival epithelium -ma in barrier for drug penetration (limiting molecule size between 20,000 to 40,000) 10PowerPoint Presentation: 4/13/2012 11 Schematic presentation of main route of drug administration and elimination from the eye. Pharmacokinetics of ocular drug delivery systemPharmacokinetics of ocular drug delivery system: 1.Transcorneal permeation from the lacrymal fluid into the anterior chamber 2. Noncorneal drug permeation across the conjunctiva and sclera into anterior uvea, 3. Drug distribution from blood stream through blood-aq.barrier into anterior chamber, 4. Elimination of drug from anterior chamber by aqueous humor turnover to trabecular meshwork and Sclemm's canal, 5. Elimination of drug from the aq. humor into the systemic circulation across the blood-aqueous barrier 6. Drug distribution from the blood into the posterior eye across the BRB, 7. Intravitreal drug administration, 8. Drug elimination from the vitreous via posterior route across the BRB. 9. Drug elimination from the vitreous via anterior route to the posterior chamber. Pharmacokinetics of ocular drug delivery systemIdeal Ophthalmic Drug Delivery System : Ideal Ophthalmic Drug Delivery System Good corneal penetration prolonged contact time of drug with corneal tissue for maximum absorption Simplicity of instillation for the patient Reduced frequency of administration Patient compliance Lower toxicity and side effects Minimize precorneal drug loss Non irritating and comfortable form Should not cause blurred vision Relatively non greasy. Appropriate rheological properties. 13Approaches in Ophthalmic Drug Delivery System : Approaches in Ophthalmic Drug Delivery System A. Approaches to Anterior Segment B. Approaches to posterior segment I. To improve ocular bioavailability II. To provide controlled & continuous ocular drug delivery Challenges for Anterior segment drug delivery following Topical administration Poor bioavailability of drugs due to precorneal loss factors Impermeability of the corneal membrane. Maintaing appropiate balance between lipophilicity & hydrophilicity of drug molecule To improve ocular bioavailability i ) Use of Penetration enhancers Altering membrane structure for transcellular transport Modifying integrity of corneal epithelium Use of adjuncts as , Chelating agents to improve stability, buffers, preservatives ( benzalkonium chloride) & surfactants (nonionic polysorbate 80 and 20) 14PowerPoint Presentation: ii) Use of Prodrug A new drug entity with High enzyme susceptibility ----- Chemically or enzymatically metabolised to active drug with modified hydrophilicity or lipophilicity to enhance corneal permeability. E.g. Epinehrine ,timolol, pilocarpine,acyclovir. iii) Use of Gel Advantages Prolongs precorneal residence time 2. Reduced systemic exposure 3. Dosing frequency reduced-once a day dose . Disadvantages 1. Little improvement in bioavailability in comparison to other systems 2. High viscosity results in blurred vision & matted eyelids –less patient acceptance 3. Sterilization is difficult during large scale production Hydrogel- controlled drug delivery systems uses polymers--PVA,Polyacrylamideas,HPMC(0.5%),carbomers,HPEC E.g. Pilopine HS ®gel,commercialized in 1986 by Alcon & more recently Timoptic-XE ® of Merck 15PowerPoint Presentation: Mucoadhesives / boiadhesives Polymeric soln. or micropraticle suspension retained in cul-de-sac through adhesive bonds with mucin or epithelium ---- increasing corneal contact time. Good flexibility in chain of polymer helps in quicker diffusion and penetration into mucin. Polymer can be neutral , synthetic or semi-synthetic e.g. polyacrylic acid,chitosan, gums like xanthan and carageenan, CMC, carbopol, HPMC Factors influencing performance of polymer are swelling characteristics hydration time molecular weight degree of crosslinking pH & extent of drug incorporation 16PowerPoint Presentation: V) . In situ gel formation Upon instillation it undergoes a phase transition in cul-de-sac to form a viscoelastic gel Prolongs residence time, improves bioavailability & patient compliance Gelling of solution (phase transition ) is triggered by 1) pH change –eg. CAP, cross linked PVA & its derivatives as carbomers 2) Temperature change – sustained drug delivery- change from soln. to gel at the temp. of the eye eg Poloxamer. 3) Ionic strength- Na + concentration in human tears (2.6 g/l) causes gelation of instilled topical material in cul-de-sac Eg Gelrite polysaccaride ( gellan gum) forms clear gel in presence of mono & or divalent cations 17PowerPoint Presentation: VI) Viscosity enhancers Prolongs precorneal residence time & improve bioavailability Hydrophilic polymers with good adhesive property extensively used - cellulose , polyalcohol, Na-CMC in ophthalmic products Polyacrylamide based hydrogels - Miotic response to Pilocarpine Polycarbophil –water insoluble cross linked Polyacrylic acid- retains drug in eye by hydrogel bonds & Mucoahhesive strength . Hyluronic acid – biocompatible & biodegradable matrix for ocular SR dosage forms Liposomes – microscopic vesicles composed of one or more concentric lipid bilayers , separated by water or aqueous buffer compartments Methods of preparation – Sonication of dispersion of phospholipids , reverse phase evaporation,solvent injection, detergent removal Liposomes acts as an ODDS partly due to their surface charge . The corneal epithelium is thinly coated with negatively charged mucin to which the positively charged surface of the lipid bind . 18PowerPoint Presentation: Ability to have an intimate contact with the corneal and conjunctival surfaces increases the probability of ocular drug absorption E.g. Dispersions of liposomes in mucoadhesive gels or coating with same polymers as hyluronic acid , Chitosan & poloxamer -enhances adherence to corneal/conjuctivital sac. Advantages Used for release of for poorly absorbable drugs with low partition coefficient and poor solubility Drugs with medium to high mol.wts.can be incorporated Sustained release and site-specific delivery is possible. Limitations 1) Difficult to manufacture in sterile operations . 2) Chemical instability. 3) Oxidative degradation of phospholipids.PowerPoint Presentation: Bilayered structural vesicles made up of nonionic surfactant , capable of encapsulating both lipophilic and hydrophilic compounds Advantages Reduces the systemic drainage improve the residence time increase ocular bioavailability Disadvantages Nonbiodegradable and nonbiocompatible in nature 20 VIII).NiosomesPowerPoint Presentation: IX) Nanoparticles/nanospheres Polymeric colloidal particles, ranging from 10 nm to 1 μ m , in which the drug is dissolved, entrapped, encapsulated, or adsorbed It stabilizes the drug & a promising drug carriers for ophthalmic application Nanospheres- small capsules with a central cavity surrounded by a polymeric membrane) nanocapsules (solid matricial spheres) - show good bioloavailability due to their bioadhesive property, increased residence time & reduced dosing frequency Eg .Nanoparticles of poly-e- caprolactone containing cyclosporin show a better corneal absorption with respect to the oily solution of the drug. 21PowerPoint Presentation: XI . Nanosuspension ( Sub-micron colloidal system ) Inert colloidal carriers (polymeric resins) and poorly water-soluble drug, suspended in an appropriate dispersion medium stabilized by surfactants Charge on the surface of nanoparticles facilitates its adhesion to the cornea prolonging the contact time to improve bioavailability of the eg .Ibuprofen was formulated in nanosuspension by using Eudragit RS100 . Advantage- enhancing the shelf life and bioavailability of the drug XII. Microemulsion (100 nm), Stable dispersions of water and oil, facilitated by a combination of surfactant and co-surfactant in a manner to reduce interfacial tension Improves bioavailability with reduced frequency of the administration characterized by higher thermodynamic stability, small droplet size and clear appearance 22PowerPoint Presentation: II. Approaches to provide controlled & continuous ocular drug delivery 1 Microparticles :- Micron sized drug particles physically dispersed in the polymer matrix or covalently bound to the polymer backbone Upon instillation in cul-de-sac, the particles reside, and the drug released from particles through diffusion, chemical reaction, and/or polymer degradation Advantages Higher precorneal residence time- continuous and sustain release of drug. improved ocular bioavailability and reduced dosing frequency Drawbacks : 1. irritation to the eye due to large particle size 2. Polymer must be Biodegradable, bioadhesive & biocompatibile E.g. 1. Pilocarpine-loaded albumin or gelatin microspheres. 2. Acyclovir-loaded chitosan microspheres. 23PowerPoint Presentation: 2. intraocular Implants Implants are in the form of solid, semi-solid, or particulate-based placed intravitreally, at the pars plana of the eye . classified as non biodegradable and biodegradable devices The ocular non biodegradable implants - more accurate control and longer release of drug than the biodegradable polymers Advantages bypasses the blood-ocular barriers provide prolonged activity , higher bioavailability with controlled release . Modulation of delivery rate by varying polymer composition. delivers constant therapeutic levels of drug directly to the site of action, avoidance of side effects due to frequent systemic and intravitreal injections. 24PowerPoint Presentation: Drawbacks Invasive technique i.e requires minor surgery. retinal detachment and intravitreal hemorrhage for intravitreal implant 3. Ocular inserts placed in the lower fornix and, less frequently, in the upper fornix or on the cornea. composed of a polymeric vehicle containing the drug and are mainly used for topical therapy . Reduction of systemic absorption (which occurs freely with eye drops via the naso-lacrimal duct and nasal mucosa) Better patient compliance , due to reduced frequency of administration and a lower incidence of visual and systemic side-effects 25PowerPoint Presentation: Possibility of targeting internal ocular tissues through non-corneal (conjunctival scleral) route . Increased shelf life with respect to aqueous solutions Exclusion of preservatives , thus reducing the risk of sensitivity reactions Accurate dosing contrary to eye drops insert can be made to contain a precise dose disadvantages of ocular inserts 1. felt by the (often oversensitive) patients as an extraneous body in the eye. This may constitute a formidable physical and psychological barrier to user acceptance and compliance migration of the insert to the upper fornix – removal difficult The occasional inadvertent loss during sleep or while rubbing the eyes, Their interference with vision , and Difficulty in placement and removal of the ocular inserts 26PowerPoint Presentation: Mechanism of Drug Release from insert A. Diffusion, B. Osmosis, C. Bio-erosion. A. Diffusion drug released continuously at a controlled rate through the membrane ( non-erodible body with pores) into the tear fluid In a soluble device - true dissolution of drug occurs mainly through polymer swelling. drug --- homogeneously dispersed in a glassy impermeable polymer. no diffusion through the dry matrix occurs . water from the tear fluid penetrate the matrix , causes it to swell---- polymer chain relaxation followed by drug diffusion . Linear amorphous polymers dissolve much faster than cross-linked or partially crystalline polymers . 27PowerPoint Presentation: B. Osmosis The insert comprises a transverse impermeable elastic membrane dividing the interior of the insert into two compartments first compartment --- is bounded by a semi-permeable membrane for Water to diffuse in and the impermeable elastic membrane with drug release aperture second compartment is bounded by an impermeable elastic membrane material and provides a reservoir for the drug in liquid or gel form. When the insert contacts aqueous environment of the eye, water diffuses into the first compartment and stretches the elastic membrane to expand the first compartment and contract the second compartment so that drug is forced through the drug release aperture. 28PowerPoint Presentation: C. Bioerosion Insert is constituted from a matrix of bioerodible material in which the drug is dispersed uniformly matrix get bioeroded upon contact of the insert with tear fluid resulting in controlled sustained release of the drug . In truly erodible devices, the rate of drug release is controlled by a chemical or enzymatic hydrolytic reaction and display zero order release kinetics 29PowerPoint Presentation: Burst mechanism Pore diffusion Erosion Release mechanismsApproaches in Ophthalmic Drug Delivery System: Approaches in Ophthalmic Drug Delivery System 31PowerPoint Presentation: Approaches to posterior segment drug delivery challenges A) Tight junctions of Blood –Retinal -Barrier(BRB) 1. limits effectiveness of IV route 2. selective permeability to lipophilic molecules high drug concentration needed over prolonged period Leading to systemic toxicity Novel Methods to Deliver Ocular Drugs to Improve Efficacy and Durability in the treatment of retinal diseases 1. Intravitreal injection - Drug placed effectively into the retina offering high drug concentration in retina & vitreuos body 32PowerPoint Presentation: Safe to posterior segment Drawbacks - pain caused by repeated injections Retinal detachment the major complication endophthalmitis , haemorrhage poor acceptance by patients. Intra vitreal devices:- a) Intra vitreal implants- ( Vitrasert ) (Bausch & Lomb) Delivers ganciclovir to control cytomegaloviral retinitis - 10 years dose . b) Retisert - a non-surgical insertion delivers Fluocinolone acetonide (FA) to control noninfectious posterior uveitis . c) Iluvien , - Nonerodable insert (3.5 mm long and 0.37 mm in diameter) for extended delivery of FA ( 0.23 or 0.45 μg of FA ) daily in patients with DME. 33Fig. 1. The Iluvien insert, A 25-g insertion system When active drug is depleted, the inert Iluvien insert is not retrieved but remains in the eye: Fig. 1. The Iluvien insert, A 25-g insertion system When active drug is depleted, the inert Iluvien insert is not retrieved but remains in the eye Figure 2. Inner view of pars plana with needle of device releasing Iluvien (Medidur FA) into the vitreous cavity. Figure 3. Schematic of Iluvien (Medidur) releasing FA near surface of retina into the vitreous cavity. 34PowerPoint Presentation: 5.NOVEL CONCEPTS IN DRUG FORMULATIONS: A Thermogels B iocompatible products used for drug transportation Liquid at room temperature and enter a gel state at body temperature. Applied topically or injected Advantage :- increasing exposure to the active drug. degradation time has been controllable in experimental studies. B Nanotechnology (Labeled as nano-ophthalmology) Advanteges improvement in drug delivery to the anterior or posterior segment, tissue repair, and strategies to facilitate surgery. 35PowerPoint Presentation: Iontophoresis :- A noninvasive method of transferring ionized drugs through membranes into cells using low electrical DC. The drug moves across the membranes by electro-osmosis . Ocular iontophoresis is classified into transcorneal , corneoscleral , or trans- scleral Advantages:- Fast, easy to use , noninvasive painless, safe, Results in the delivery of a high concentration of the drug to a specific site. Can modulate dosage (less risk of toxicity) To treat several ophthalmic diseases in the posterior segment of the eye.It useful for the treatment of bacterial keratitis , Iontophoretic application of antibiotics enhances their bactericidal activity and reduce the severity of disease 36 Visulex TM -system with applicator & a dose controller for transscleral iontophoresis: Visulex TM - system with applicator & a dose controller for transscleral iontophoresisPowerPoint Presentation: ICH guidelines for ODDS :- ICH mainly focuses on - A. Nonclinical safety evaluation of drugs by various study designs B. Morphological evaluation Nonclinical safety evaluation of drugs by various study designs 1. Nonclinical toxicity studies – Depends on clinical & non clinical factors- a) Clinical route & indication b) Pharmacokinetic considerations c) age & sex of patient d) Previous clinical or nonclinical information from other ocular route 2. Ocular Pharmacokinetic Studies Usually in one species to examine ADME in various ocular compartments 38PowerPoint Presentation: 3. Ocular Tolerability or Irritancy test- Recommended by European regulatory authorities Conducted in rabbits, for NCE or reformulation of marketed preparation Study is evaluated by Biomicroscopy Tonometry Electro Retino Gram (ERG) histopathology 4. Systemic toxicological studies for evaluation of systemic tissues Conducted when route such as IV or oral route used in one species for FIHS evaluation by Fluorescien angiography & Ocular computed tomography or vitreal Pharmacokinetics 39PowerPoint Presentation: 2. Species & strain parameters- Non rodents , such as rabbits, dogs, and/or monkeys the species of choice in ocular toxicity and pharmacokinetic studies. Rabbits are the most common species used for ocular toxicity testing Rabbit eye is large enough to perform accurate ocular injections or delivery by other methods. A non pigmented rabbit strain, such as the New Zealand White (NZW), is usually acceptable Rat eye – Too small for ocular implant designed for human so regulatory resistance on its use The monkey eye most closely resembles the human eye higher sequence homology to humans with regard to anatomy and physiology, including presence of a macula, 40PowerPoint Presentation: Morphological Assessment :- Methodology 1. Collection & fixation 2. Trimming & sectioning 3. Morphometric species comparison 4.Species differences in vitreal volume estimating Animal/Human safety multiples 41PowerPoint Presentation: 1 Collection & fixation – In ocular toxicological studies both untreated & treated eyes & surrounding ocular structures such as upper & lower eyelids ,lacrimal gland ,optic nerve & adjascent muscles should be collected. Morphometric species comparison- In ocular toxicological studies for posterior –segment diseases NZW rabbits & monkeys are two the most common species are used. The ciliary body and pars plana region is important in intravitreal implant studies, site for surgical penetration of the posterior segment The monkey s pars plana area is also proportionately more extensive in monkeys than in rabbits so monkeys preffered for implant studies 42PowerPoint Presentation: The future challenges in ODDS are as follows 1. The ocular bioavailability must be increased from less than 1% to 15-20% of the administered dose. 2. There is a need to develop new drug candidates for ocular use . 3. Fully exploit the potential of noncorneal routes , especially for ionic/water soluble moieties and also drug molecules with a preferential corneal absorption 4. minimum absorption of drug through nasal mucosa should be explored. 5. Appropriate design and packaging of these delivery systems needs further research. 43CASE STUDY: CASE STUDY Fluconazole Ocular Inserts: Formulation & Evaluation Publication: Journal of Pharmaceutical Sciences and Research Author: Rao, Purna Chandra M Date published: June 1, 2010 In the present study, it was aimed to prepare and evaluate ocular films containing fluconazole along with hydrophilic and hydrophobic polymers either alone or in combination at different concentrations with better solubility and longer duration of action delivering the drug in zero order kinetics 44PowerPoint Presentation: 45 Composition Of Fluconazole Ocular Films Ingdts Polyvinyl Poly vinyl Hydroxy Propyl Propylene Glycerine Water Fluconazole % w/v Alcohol Pyrrolidn. methyl cellulose Glycol (PVA) (PVP) (HPMC) (PG) (glyn.) (W) (FL) F -1 4 _ _ 0.2 _ 100 0.3 F -2 5 _ _ 0.2 _ 100 0.3 F -3 4 1 _ 0.2 _ 100 0.3 F -4 4 1.5 _ 0.2 _ 100 0.3 F -5 4 2.5 _ 0.2 _ 100 0.3 F -6 _ _ 2 4.98 2.5 100 0.3 F -7 _ _ 3 4.98 2.5 100 0.3CASE STUDY: CASE STUDY II. Preparation of Ocular inserts:- Weighing of all ingredients Uniform mixing of all ingredients as per procedure . Dissolving in solvents & making volume. Sonication by ultra sonicator at specified time. Allowing solutions to stand for given time . Moulding & evaporation by hot air oven at 35 ℃ for 3 hrs. Detaching from mould & uniform sizing into square films with the help of a sharp edged die. 46CASE STUDY: CASE STUDY 47CASE STUDY: CASE STUDY 48PowerPoint Presentation: 49CASE STUDY: CASE STUDY Evaluation of F -1 To F - 7 Formuln . Wt/sq.cm. Thickness Surface P H Folding FL in 1 sq. cm mm endurance in ocular fi lm F- 1 Min. Min. F – 2 Max. F – 3 Min. Min F – 4 Min. F – 5 Max. Max. 6.8 Max. F – 6 F – 7 Max. 50Results : Results Fluconazole ocular films were prepared using film forming polymers Technique:- Solvent casting technique- Seven formulations Characterization:-characterized by means of film thickness, weight variation, folding endurance ,surface pH, and in- vitro drug release to determine the amount of drug release from selected film formulae using excised goat cornea . Ocular inserts prepared were smooth and passed all the evaluation tests performed. Formulation F5 shows a maximum cumulative percentage drug release of 69.02 % at the end of 2 hours through excised goat cornea. The drug in the films was found to be activ e against selected fungal species as was proved by microbial efficacy studies The ocular films of formulation F-5 showed appreciable result in the entire evaluation tests & is most suitable for extending further study. 4/13/2012 51PATENTS: PATENTS Patent Number Filing date Issue date OriginalAssignee US4116241 Dec 15, 1976 Sep 26, 1978 Alza Corporation US7943162 Dec 7, 2006 May 17, 2011 Alcon, Inc. US7993634 Dec 15, 2005 Aug 9, 2011 Allergan , Inc. US7998497 Apr 2, 2007 Aug 16, 2011 QLT Inc. US8105622 Aug 8, 2007 Jan 31, 2012 Incept LLC. US8119154 Apr 30, 2004 Feb 21, 2012 Allergan , Inc. 52CONCLUSION: CONCLUSION Ocular drug delivery systems provide local as well as systemic delivery of the drugs. The novel advanced delivery systems offer more protective and effective means of the therapy for the nearly inaccessible diseases or syndromes of eyes. Progress in the field of ocular drug delivery has been established recently with controlled loading and sustained release. Hence, effective drug delivery and targeting is faced by challenges to overcome these barriers. 53REFERENCES: 1. Lee VHL, Robinson JR: Topical ocular drug delivery: recent developments and future challenges. Journal of Ocular Pharmacology 1986; 2: 67–108 2. Lang J C. Ocualar drug delivery conventional ocular formulation. Advanced drug delivery review 1995;16:39-43. 3. K Basavaraj, Nanjawade, Manvi FV and Manjappa AS: In situ-forming hydrogels for sustained ophthalmic drug delivery. Journal of Controlled Release 2007; 122: 119–134. 4. Sahoo KS, fahima SAD, kumar K: Nanotechnology in ocular drug delivery, Drug delivery today 2008; 13: 144-151. 54 REFERENCESPowerPoint Presentation: Thank You 55 You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.