Drug Delivery to the Posterior Segment of the Eye: Biopharmaceutic and Pharmacokinetic Considerations

The treatment of the posterior-segment ocular diseases, such as age-related eye diseases (AMD) or diabetic retinopathy (DR), present a challenge for ophthalmologists due to the complex anatomy and physiology of the eye. This specialized organ is composed of various static and dynamic barriers that restrict drug delivery into the target site of action. Despite numerous efforts, effective intraocular drug delivery remains unresolved and, therefore, it is highly desirable to improve the current treatments of diseases affecting the posterior cavity. This review article gives an overview of pharmacokinetic and biopharmaceutics aspects for the most commonly-used ocular administration routes (intravitreal, topical, systemic, and periocular), including information of the absorption, distribution, and elimination, as well as the benefits and limitations of each one. This article also encompasses different conventional and novel drug delivery systems designed and developed to improve drug pharmacokinetics intended for the posterior ocular segment treatment.

Download Full-text

Novel delivery systems of active substances for intraocular administration

Anales de la Real Academia Nacional de Farmacia ◽

10.53519/analesranf.2021.87.03.08 ◽

2021 ◽

Vol 87 (87(03)) ◽

pp. 331-338

Author(s):

Rocío Herrero Vanrell

Keyword(s):

Drug Delivery ◽

Drug Delivery Systems ◽

The Elderly ◽

Delivery Systems ◽

Posterior Segment ◽

Age Related Macular Degeneration ◽

Multifactorial Diseases ◽

Age Related ◽

Intraocular Drug Delivery ◽

Active Substances

Neurodegenerative pathologies affecting the posterior segment of the eye such as diabetic retinopathy, age related macular degeneration and glaucoma are among the main causes of blindness in the world. They have in common that are cronic, multifactorial and in some cases related with the elderly. The treatment of these pathologies require to maintain therapeutic concentrations in the posterior segment thanks to the use of successive intraocular injections which are associated to secondary effects being poor tolerated by patients. Intraocular drug delivery systems emerged as an alternative to frequent injections as they are able to deliver the therapeutic agent in a controlled fashion into the eye after a single administration. Depending on the biomaterial these delivery systems are biodegradable or non biodegradable. Attending to their sizes, drug delivery systems are classified in implants (>1mm), microsystems (1-1000μm) y nanosystems (1-1000nm). Biodegradable microspheres emerge as therapeutic tools of great interest for the treatment of neurodegenerative pathologies as they can encapsulate active substances of distinct nature and provide release profiles tailoring with clinical needs. Furthermore, it is possible to administer different amounts of microspheres which correspond to the most adequated doses of the medicine in a personalized therapy. The simultaneous encapsulation of several active substances in the microspheres are of great interest in the treatment of multifactorial diseases covering different therapeutic targets.

Download Full-text

REVIEW ON ANTIMICROBIAL AND ANTI ACNE POTENTIAL OF KAEMPFERIA SPP.

PLANT ARCHIVES ◽

10.51470/plantarchives.2021.v21.no1.112 ◽

2021 ◽

Vol 21 (no 1) ◽

Author(s):

Subhash Chandra Mishra ◽

Shailesh Jain

Keyword(s):

Drug Delivery ◽

Health Care ◽

Minimum Inhibitory Concentration ◽

Bacterial Resistance ◽

Inhibitory Concentration ◽

Age Groups ◽

Chebulagic Acid ◽

Site Of Action ◽

Novel Drug ◽

Aromatic Oils

Acne is a general but somber skin disease, which affects approximately 80% adolescents and young adults in 11–30 age groups. 42.5 % of men and 50.9 % of women keep onto suffer from this disease into their twenties. Bacterial resistance is now at the alarming stage due to the irrational use of antibiotics. Hence, search for new lead molecule/bioactive and rational delivery of the existing drug (for better therapeutic effect) to the site of action is the need of the hour. Plants and plant-derived products have been an integral part of health care system since time immemorial. Therefore, plants that are currently used for the treatment of acne and those with a high potential are summarized in the present review. Most active plant extracts, namely, P. granatum, M. alba, A. anomala, and M. aquifolium exhibit minimum inhibitory concentration (MIC) in the range of 4–50 µg/mL against P. acnes, while aromatic oils of C. obovoides, C. natsudaidai, C. japonica, and C. nardus possess MICs 0.005–0.6 ?L/mL and phytomolecules such as rhodomyrtone, pulsaquinone, hydropulsaquinone, honokiol, magnolol, xanthohumollupulones, chebulagic acid and rhinacanthin-C show MIC in the range of 0.5–12.5 ?g/mL. Novel drug delivery tant plant leads in the treatment of acne have also been discussed.

Download Full-text

An Overview of Robotic Capsules for Drug Delivery to the Gastrointestinal Tract

Journal of Clinical Medicine ◽

10.3390/jcm10245791 ◽

2021 ◽

Vol 10 (24) ◽

pp. 5791

Author(s):

Pablo Cortegoso Valdivia ◽

Alexander R. Robertson ◽

Nanne K. H. De Boer ◽

Wojciech Marlicz ◽

Anastasios Koulaouzidis

Keyword(s):

Drug Delivery ◽

Targeted Therapy ◽

Gastrointestinal Tract ◽

Small Bowel ◽

Drug Delivery Systems ◽

Rapid Evolution ◽

Gi Tract ◽

Standard Drug ◽

Anatomy And Physiology ◽

Complex Anatomy

The introduction of capsule endoscopy two decades ago marked the beginning of the “small bowel revolution”. Since then, the rapid evolution of microtechnology has allowed the development of drug delivery systems (DDS) designed to address some of the needs that are not met by standard drug delivery. To overcome the complex anatomy and physiology of the gastrointestinal (GI) tract, several DDS have been developed, including many prototypes being designed, built and eventually produced with ingenious drug-release mechanisms and anchoring systems allowing targeted therapy. This review highlights the currently available systems for drug delivery in the GI tract and discusses the needs, limitations, and future considerations of these technologies.

Download Full-text

DIABETIC RETINOPATHY: AN INCLUSIVE REVIEW ON CURRENT TREATMENT AND MANAGEMENT APPROACHES

Asian Journal of Pharmaceutical and Clinical Research ◽

10.22159/ajpcr.2018.v11i11.26949 ◽

2018 ◽

Vol 11 (11) ◽

pp. 54

Author(s):

Jyothi S L ◽

Vishal Gupta N

Keyword(s):

Drug Delivery ◽

Diabetic Retinopathy ◽

Delivery System ◽

Life Quality ◽

Current Treatment ◽

Posterior Uveitis ◽

Posterior Segment ◽

Age Related Macular Degeneration ◽

Age Related ◽

New Formulation

Diabetic retinopathy (DR) is a complication which occurs due to diabetes mellitus leading to loss of vision and hindering the quality of patient life by damaging the layer of retina at the posterior segment of the eye. According to the survey around 285 million peoples are suffering from visual loss out of these 65% of people are more than 50 years old and 82% of blind patients are more than 50 years old. The diseases that occur in the posterior segment of the eye like, cytomegalovirus retinitis, posterior uveitis, age related macular degeneration and diabetic retinopathy needs a novel delivery system that can improve the concentration of drugs that reaches posterior segment of the eye. The development of new drug delivery system gained more importance in the field of research in which nanotechnology is the most considered approach. The nanotechnology-based systems such as nanoparticles, nanoliposomes, niosomes, nanomicelles, nanoemulsions, nanogels, cyclodextrins, dendrimers, and quantum dots are developed as a new formulation for drug delivery. The rationale behind the nanoparticle systems is its ability to formulate a sustained, controlled release dosage form, painless, safe, non-invasive system to overcome the major barriers in the treatment of DR. Based on the nanoparticles, some approaches are exploited for more effective conveyance of drug toward the posterior segment. Thus, these advanced delivery systems progress the therapeutic efficacy of the drug and patient’s obedience and life quality. In this review, the new therapeutic treatments and their managements were discussed and methods of drug delivery to reach the posterior segment of eye.

Download Full-text

Lipid Nanoparticles for the Posterior Eye Segment

Pharmaceutics ◽

10.3390/pharmaceutics14010090 ◽

2021 ◽

Vol 14 (1) ◽

pp. 90

Author(s):

Lorena Bonilla ◽

Marta Espina ◽

Patricia Severino ◽

Amanda Cano ◽

Miren Ettcheto ◽

...

Keyword(s):

Drug Delivery ◽

Solid Lipid Nanoparticles ◽

Drug Carriers ◽

Lipid Nanoparticles ◽

Posterior Segment ◽

Preparation Methods ◽

Administration Routes ◽

Drug Conjugates ◽

Different Types ◽

Ocular Distribution

This review highlights the application of lipid nanoparticles (Solid Lipid Nanoparticles, Nanostructured Lipid Carriers, or Lipid Drug Conjugates) as effective drug carriers for pathologies affecting the posterior ocular segment. Eye anatomy and the most relevant diseases affecting the posterior segment will be summarized. Moreover, preparation methods and different types and subtypes of lipid nanoparticles will also be reviewed. Lipid nanoparticles used as carriers to deliver drugs to the posterior eye segment as well as their administration routes, pharmaceutical forms and ocular distribution will be discussed emphasizing the different targeting strategies most recently employed for ocular drug delivery.

Download Full-text

A comprehensive review on Liposomes: a novel drug delivery system

Journal of Drug Delivery and Therapeutics ◽

10.22270/jddt.v8i6.2071 ◽

2018 ◽

Vol 8 (6) ◽

pp. 400-404

Author(s):

Harshita Mishra ◽

Vaishali Chauhan ◽

Kapil Kumar ◽

Deepak Teotia

Keyword(s):

Drug Delivery ◽

Controlled Release ◽

Drug Delivery System ◽

Delivery System ◽

Liposomal Drug ◽

Hydrophilic Drug ◽

Site Of Action ◽

Novel Drug Delivery System ◽

Novel Drug ◽

Lipophilic Character

Liposome was derived from two Greek words “Lipos meaning fat and Soma meaning body”. Liposome were spherical shaped vesicles consist of phospholipids and cholesterol. Due to their size hydrophobic and lipophilic character they are very promising system for drug delivery. This novel drug delivery system aims to target the drug directly to the site of action. Liposomes are very biocompatible and stable and have unique property to entrap both hydrophilic drug and lipophilic drug (amphiphatic nature) to its compartment and lead to controlled release effect. They are of 0.05- 5.0 micrometer in diameter. Liposomes are used for the treatment of various diseases like tumors or cancer. This article provides an overview of Liposomal Drug Delivery System and various aspects related to liposome that can be studied. Keywords: Liposomes, novel delivery, amphiphatic, controlled release.

Download Full-text

Cannulation of the Suprachoroidal Space: A Novel Drug Delivery Methodology to the Posterior Segment

American Journal of Ophthalmology ◽

10.1016/j.ajo.2006.05.045 ◽

2006 ◽

Vol 142 (5) ◽

pp. 777-787.e2 ◽

Cited By ~ 85

Author(s):

Timothy W. Olsen ◽

Xiao Feng ◽

Kathy Wabner ◽

Stanley R. Conston ◽

David H. Sierra ◽

...

Keyword(s):

Drug Delivery ◽

Posterior Segment ◽

Suprachoroidal Space ◽

Novel Drug

Download Full-text

Posterior segment drug delivery for the treatment of exudative age-related macular degeneration and diabetic macular oedema

British Journal of Ophthalmology ◽

10.1136/bjophthalmol-2018-313462 ◽

2019 ◽

Vol 103 (10) ◽

pp. 1356-1360 ◽

Cited By ~ 3

Author(s):

Chee Wai Wong ◽

Tina T Wong

Keyword(s):

Drug Delivery ◽

Macular Degeneration ◽

Macular Oedema ◽

Diabetic Macular Oedema ◽

Cell Penetrating Peptides ◽

Posterior Segment ◽

Age Related Macular Degeneration ◽

Preclinical Studies ◽

Exudative Amd ◽

Age Related

Inhibitors of vascular endothelial growth factors are used to treat a myriad of retinal conditions, including exudative age-related macular degeneration (AMD), diabetic macular oedema (DME) and diabetic retinopathy. Although effective, long-term efficacy is limited by the need for frequent and invasive intravitreal injections. The quest for sustained action therapeutics that can be delivered to target tissue in the least invasive manner is an arduous endeavour that has ended in premature failure for several technologies in Phase II or III trials. Nevertheless, there have been promising preclinical studies, and more are on the horizon: port delivery systems for the treatment of exudative AMD have entered Phase III trials and a wide array of preclinical studies have demonstrated the potential for nanoparticles, such as liposomes, dendrimers and cell penetrating peptides to deliver therapeutics into the posterior segment via minimally invasive routes. In this review, we discuss the challenges posed by ocular barriers for drug penetration and present the recent advancements of the most pertinent drug delivery platforms with a focus on the treatment of exudative AMD and DME.

Download Full-text

Promising Approach in the Treatment of Glaucoma Using Nanotechnology and Nanomedicine-Based Systems

Molecules ◽

10.3390/molecules24203805 ◽

2019 ◽

Vol 24 (20) ◽

pp. 3805 ◽

Cited By ~ 7

Author(s):

Fidiniaina Rina Juliana ◽

Samuel Kesse ◽

Kofi Oti Boakye-Yiadom ◽

Hanitrarimalala Veroniaina ◽

Huihui Wang ◽

...

Keyword(s):

Drug Delivery ◽

Future Research ◽

Eye Drops ◽

Disease Treatment ◽

Ocular Tissues ◽

Human Eye ◽

Anatomy And Physiology ◽

Novel Approach ◽

Novel Drug ◽

Research Frontiers

Glaucoma is considered a leading cause of blindness with the human eye being one of the body’s most delicate organs. Ocular diseases encompass diverse diseases affecting the anterior and posterior ocular sections, respectively. The human eye’s peculiar and exclusive anatomy and physiology continue to pose a significant obstacle to researchers and pharmacologists in the provision of efficient drug delivery. Though several traditional invasive and noninvasive eye therapies exist, including implants, eye drops, and injections, there are still significant complications that arise which may either be their low bioavailability or the grave ocular adverse effects experienced thereafter. On the other hand, new nanoscience technology and nanotechnology serve as a novel approach in ocular disease treatment. In order to interact specifically with ocular tissues and overcome ocular challenges, numerous active molecules have been modified to react with nanocarriers. In the general population of glaucoma patients, disease growth and advancement cannot be contained by decreasing intraocular pressure (IOP), hence a spiking in future research for novel drug delivery systems and target therapeutics. This review focuses on nanotechnology and its therapeutic and diagnostic prospects in ophthalmology, specifically glaucoma. Nanotechnology and nanomedicine history, the human eye anatomy, research frontiers in nanomedicine and nanotechnology, its imaging modal quality, diagnostic and surgical approach, and its possible application in glaucoma will all be further explored below. Particular focus will be on the efficiency and safety of this new therapy and its advances.

Download Full-text

Intravitreal Dexamethasone Implant as a Sustained Release Drug Delivery Device for the Treatment of Ocular Diseases: A Comprehensive Review of the Literature

Pharmaceutics ◽

10.3390/pharmaceutics12080703 ◽

2020 ◽

Vol 12 (8) ◽

pp. 703

Author(s):

Claudio Iovino ◽

Rodolfo Mastropasqua ◽

Marco Lupidi ◽

Daniela Bacherini ◽

Marco Pellegrini ◽

...

Keyword(s):

Drug Delivery ◽

Drug Delivery Device ◽

Anatomy And Physiology ◽

Comprehensive Collection ◽

Complex Anatomy ◽

Intravitreal Dexamethasone Implant ◽

First Choice ◽

Ocular Disorders ◽

Intravitreal Dexamethasone ◽

Endothelial Growth Factors

Drug delivery into the vitreous chamber remains a great challenge in the pharmaceutical industry due to the complex anatomy and physiology of the eye. Intravitreal injection is the mainstream route of drug administration to the posterior segment of the eye. The purpose of this review is to assess the current literature about the widening use of the intravitreal 0.7 mg dexamethasone (Dex) implant, and to provide a comprehensive collection of all the ocular disorders that benefit from Dex administration. Although anti-vascular endothelial growth-factors (VEGFs) have been largely indicated as a first-choice level, the Dex implant represents an important treatment option, especially in selected cases, such as vitrectomized eyes or patients in whom anti-VEGF failed or are contraindicated. In this article, the safety profile as well as the list of the possible complications related to intravitreal Dex injection are also discussed.

Download Full-text