Chitosan microspheres in novel drug delivery systems.

The study aims to determine the drug therapy of any disease to attain the desired therapeutic concentration of the drug in plasma or at the site of action and maintain it for the entire duration of treatment. A drug on being used in conventional dosage forms leads to unavoidable fluctuations in the drug concentration leading to under medication or overmedication and increased frequency of dose administration as well as poor patient compliance. To minimize drug degradation and loss, to prevent harmful side effects and to increase drug bioavailability various drug delivery and targeting systems are currently under development. Handling the treatment of severe disease conditions has necessitated the development of innovative ideas to modify drug delivery techniques. Drug carrier systems include polymers, micelles, microcapsules, Liposomes and lipoproteins etc. Different polymer carriers exert different effects on drug delivery. Synthetic polymers are usually no biocompatible, non-biodegradable and expensive. Natural polymers such as chitin and chitosan are devoid of such problems. Chitosan is a biocompatible, biodegradable, and nontoxic natural polymer with excellent film-forming ability. Being of cationic character, chitosan is able to react with polyamines giving rise to polyelectrolyte complexes. Hence chitosan has become a promising natural polymer for the preparation of microspheres or nanospheres and microcapsules. This review focuses on the preparation, characterization of chitosan microspheres and their role in novel drug delivery systems. This review also aims to include the process variables factors that affect the release of drugs from the microspheres.

The main goal of pharmacotherapy for any condition is to achieve and maintain the intended curative quantity of the therapeutic agent in the bloodstream or at the desired site during the whole course of treatment. Conventional drug dosage forms frequently cause inescapable changes in drug concentration, which have the negative effects of insufficient or excessive dose, frequent administration, and poor patient adherence. In this regard, various medication delivery and targeting methods are being developed to address these issues and improve overall drug bioavailability. Polymers, micelles, microcapsules, liposomes, and lipoproteins are a few examples of such drug carrier systems. The delivery of drugs is affected differently by each polymer carrier. Typically, synthetic polymers are expensive, persistent, and non-biocompatible. Natural polymers like chitin and chitosan do not present these problems. A naturally occurring polymer called chitosan (CS) is frequently used in medicinal applications because of its affordability, biodegradability, biocompatibility, non-toxic makeup, and capacity to cling to mucosal surfaces. Because of its cationic characteristics, CS can interact with polyanions to produce polyelectrolyte complexes. CS has thus shown to be particularly useful in improving the dissolving of insoluble medicines and in multiparticulate drug delivery. Chitosan has emerged as a prospective natural polymer for the formulation of microspheres and microcapsules. Ionotropic gelation, spray drying, emulsion phase separation, simple coacervation, and complex coacervation are some of the techniques used in chitosan microencapsulation. This chapter will primarily concentrate on the synthesis and characterization of chitosan microspheres, as well as their use in novel drug delivery systems.

Concepts and System Design for the Rate-Controlled Drug Delivery Fundamentals of Rate-Controlled Drug Delivery Oral Drug Delivery and Delivery Systems Mucosal Drug Delivery: Potential Routes for Noninvasive Systemic Administration Nasal Drug Delivery and Delivery Systems Ocular Drug Delivery and Delivery Systems Transdermal Drug Delivery and Delivery Systems Parenteral Drug Delivery and Delivery Systems Vaginal Drug Delivery and Delivery Systems Intrauterine Drug Delivery and Delivery Systems Systemic Delivery of Peptide-Based Pharmaceuticals Regulatory Considerations in Controlled Drug Delivery

MODERN STATE OF CREATION, PRODUCTION AND RESEARCH OF DRUGS

Advances in Drug Delivery

BackgroundPolymeric drug delivery systems have been achieved great development in the last two decades. Polymeric drug delivery has defined as a formulation or a device that enables the introduction of a therapeutic substance into the body. Biodegradable and bio-reducible polymers make the magic possible choice for lot of new drug delivery systems. The future prospects of the research for practical applications has required for the development in the field.Main bodyNatural polymers such as arginine, chitosan, dextrin, polysaccharides, poly (glycolic acid), poly (lactic acid), and hyaluronic acid have been treated for polymeric drug delivery systems. Synthetic polymers such as poly (2-hydroxyethyl methacrylate), poly(N-isopropyl acrylamide)s, poly(ethylenimine)s, dendritic polymers, biodegradable and bio-absorbable polymers have been also discussed for polymeric drug delivery. Targeting polymeric drug delivery, biomimetic and bio-related polymeric systems, and drug-free macromolecular therapeutics have also treated for polymeric drug delivery. In polymeric gene delivery systems, virial vectors and non-virial vectors for gene delivery have briefly analyzed. The systems of non-virial vectors for gene delivery are polyethylenimine derivatives, polyethylenimine copolymers, and polyethylenimine conjugated bio-reducible polymers, and the systems of virial vectors are DNA conjugates and RNA conjugates for gene delivery.ConclusionThe development of polymeric drug delivery systems that have based on natural and synthetic polymers are rapidly emerging to pharmaceutical fields. The fruitful progresses have made in the application of biocompatible and bio-related copolymers and dendrimers to cancer treatment, including their use as delivery systems for potent anticancer drugs. Combining perspectives from the synthetic and biological fields will provide a new paradigm for the design of polymeric drug and gene delivery systems.

Simulation-based approaches for drug delivery systems: Navigating advancements, opportunities, and challenges

Successful treatment of most of the diseases is limited by a lack of safe and effective methods of drug delivery. Drug delivery methods have significant effects on the pharmacological efficacy of a drug. Every drug has an optimum concentration range within which maximum benefit is derived; and concentrations above or below the range can be toxic or provide no therapeutic benefits at all. Therefore, development of an efficient drug delivery system remains an important challenge in medicine, and this can be achieved only through multidisciplinary approaches to the mechanisms of delivery of drugs to targets in tissues. Thus, several drug delivery and drug targeting systems are currently being developed. Targeting is an ability to direct the drug(s) to the desired site. There are two major mechanisms, viz., active and passive for drug targeting. Controlled drug release and subsequent biodegradation are also indispensable for developing successful formulations. Colloidal drug vehicles such as micelles, vesicles, liquid crystal dispersions, and nanomaterials consisting of miniscule nanoparticles of 5 - 200 nm diameter have shown great promise as drug delivery systems. In this context, past decades have witnessed certain major advancements. This review article emphasizes on these advances in the field of drug delivery systems.

Introduction: Sub dermal implants are recognized as a useful drug delivery system. A majority of drug delivery systems using natural biodegradable polymers have been based on proteins and polysaccharides. To minimize drug degradation and loss, to prevent harmful side-effects and to increase drug bioavailability and the fraction of drug accumulated in the required zones, various drug delivery and drug targeting systems are currently under development 1. An ideal drug carrier must be biostable, biocompatible with minimal tissue polymer interaction, non-toxic, non-carcinogenic, economical, providing better therapeutic outcome and greater patient compliance. Aims and Objectives: The aim of the study was to evaluate the tissue compatibility to Gelatin, Gelatin+Chitosan based polymeric implants at subdermal region of neck and thigh of rabbit by histopathological examination. Results: Acute inflammatory changes congestion and neutrophilic infiltration were seen at 15 days after implantation along with few lymphocytes and fragments of polymer. At 30 days, there was lymphomononuclear infiltration with no evidence of necrosis, no foreign body reaction nor other changes like granuloma, metaplasia. Similar features were identified at 60 days and 90 days and residual polymer was also not seen indicating biodegradability of the polymeric implants. Conclusion: Gelatin; Gelatin +Chitosan based polymeric implants showed biodegradability and biocompatibility at the subdermal region of the rabbits.

Silk is a natural polymer with unique physicochemical and mechanical properties which makes it a desirable biomaterial for biomedical and pharmaceutical applications. Silk fibroin (SF) has been widely used for preparation of drug delivery systems due to its biocompatibility, controllable degradability and tunable drug release properties. SF-based drug delivery systems can encapsulate and stabilize various small molecule drugs as well as large biological drugs such as proteins and DNA to enhance their shelf lives and control the release to enhance their circulation time in the blood and thus the duration of action. Understanding the properties of SF and the potential ways of manipulating its structure to modify its physicochemical and mechanical properties allows for preparation of modulated drug delivery systems with desirable efficacies. This review will discuss the properties of SF material and summarize the recent advances of SF-based drug and gene delivery systems. Furthermore, conjugation of the SF to other biomolecules or polymers for tissue-specific drug delivery will also be discussed.

Проведено огляд літературних джерел щодо розробки та дослідження осмотичних систем вивільнення та доставки лікарських речовин

Natural polymers, or biopolymers, are widely utilized in regenerative medicine and tissue engineering. These polymers, derived from proteins, polysaccharides, and nucleic acids, serve as biomaterials for scaffolds, drug delivery systems, and bioactive materials that mimic the extracellular matrix. They offer advantages such as biocompatibility, biodegradability, versatility, and integration with gene therapy. Collagen, gelatin, chitosan, hyaluronic acid, fibrin, and alginate are commonly used natural polymers in regenerative medicine. They promote cell growth, tissue formation, wound healing, and tissue regeneration. Natural polymers also play a crucial role in controlled drug and gene delivery systems, providing safe and effective alternatives to synthetic polymers. Moreover, they contribute to developing bioactive and bio-functional materials, including hydrogels, which mimic natural biological processes and have applications in tissue engineering, drug delivery, and wound healing. Overall, natural polymers hold great promise for advancing regenerative medicine and tissue engineering. However, several challenges impede the widespread adoption and utilization of natural polymers in regenerative medicine. These challenges include variations in batch-to-batch composition, limited mechanical strength, rapid degradation rates, immunogenicity concerns, and difficulties achieving precise control over their properties. Overcoming these challenges necessitates a comprehensive understanding of the structure-function relationships of natural polymers and the development of innovative processing techniques to enhance their mechanical properties and stability. The future of natural polymers in regenerative medicine holds immense potential. Ongoing research efforts focus on refining their properties, tailoring their degradation rates, and integrating them with advanced technologies like 3D bioprinting and nanotechnology. By leveraging these advancements, natural polymers can be further optimized for specific tissue engineering applications, enabling the creation of patient-specific scaffolds, enhanced wound healing materials, and personalized drug delivery systems. Additionally, harnessing the innate bioactivity of natural polymers and their interactions with cells and tissues opens new avenues for the development of bioactive materials that promote tissue regeneration and healing.

Part I: Pharmacological Considerations for Drug Delivery Systems in Cancer Medicine Systemically Administered Drugs Reginald B. Ewesuedo and Mark J. Ratain Regional Administration of Antineoplastic Drugs Maurie Markman Theoretical Analyses and Simulations of Anticancer Drug Delivery Ardith W. El-Kareh and Timothy W. Secomb Part II: Technologies Available for Use in Cancer Drug Delivery Systems Biopolymers for Parenteral Drug Delivery in Cancer Treatment Wolfgang Friess Hydrogels in Cancer Drug Delivery Systems Sung-Joo Hwang, Namjin Baek, Haesun Park, and Kinam Park Microparticle Drug Delivery Systems Duane T. Birnbaum and Lisa Brannon-Peppas Polyethylene Glycol Conjugation of Protein and Small Molecule Drugs: Past, Present, and Future Robert G. L. Shorr, Michael Bentley, Simon Zhsao, Richard Parker, and Brendan Whittle Emulsions As Anticancer Delivery Systems S. Esmail Tabibi Part III. Current Applications: Products Approved or in Advanced Clinical Development Liposomal Drug Delivery Systems for Cancer Therapy Daryl C. Drummond, Dmitri Kirpotin, Christopher C. Benz, John W. Park, and Keelung Hong Gliadel(R): A New Method for the Treatment of Malignant Brain Tumors Francesco DiMeco, Henry Brem, Jon D. Weingart, and Alessandro Olivi Intralesional Chemotherapy with Injectable Collagen Gel Formulations Elaine K. Orenberg Sustained-Release Drug Delivery with DepoFoam Sankaram B. Mantripragada and Stephen B. Howell Cancer Vaccines Susanne Osanto Part IV. Future Directions: Novel Cancer Drug Targets and Delivery Systems Gene Therapy of Cancer Susanne Osanto Progress in Antisense Technology Stanley T. Crooke Tumor Vaccines Francesco M. Marincola Diagnosis and Treatment of HumanDisease Using Telomerase As a Novel Target Lynne W. Elmore and Shawn E. Holt Index

Chitosan is a weak cationic polysaccharide composed essentially of β(1 → 4) linked glucosamine units together with some N‐acetylglucosamine units. It is obtained by extensive deacetylation of chitin, a polysaccharide common in nature. Chitosan is a biocompatible, biodegradable, and nontoxic natural polymer that exhibits excellent film‐forming ability. As a result of its cationic character, chitosan is able to react with polyanions giving rise to polyelectrolyte complexes. Therefore, because of these interesting properties, it has become the subject of numerous scientific reports and patents on the preparation of microspheres and microcapsules. The techniques employed to microencapsulate with chitosan include, among others, ionotropic gelation, spray drying, emulsion phase separation, simple and complex coacervation, and polymerization of a vinyl monomer in the presence of chitosan. The aim of this work is to review some of the more common techniques used and to put forward the results obtained by our research group in preparing chitosan‐based microcapsules: for taste masking and improving the stability of a nutritional oil, the sustained release of drugs, as well as the preparation of chitosan superparamagnetic microcapsules for the immobilization of enzymes.Scanning electron micrograph of some superparamagnetic chitosan particles and magnetic hysteresis loop of the microparticles.magnified imageScanning electron micrograph of some superparamagnetic chitosan particles and magnetic hysteresis loop of the microparticles.

Lipid-based innovations have achieved new heights during the last few years as an essential component of drug development. The current challenge of drug delivery is liberation of drug agents at the right time in a safe and reproducible manner to a specific target site. A number of novel drug delivery systems has emerged encompassing various routes of administration, to achieve controlled and targeted drug delivery. Microparticulate lipoidal vesicular system represents a unique technology platform suitable for the oral and systemic administration of a wide variety of molecules with important therapeutic biological activities, including drugs, genes, and vaccine antigens. The success of liposomes as drug carriers has been reflected in a number of liposome-based formulations, which are commercially available or are currently undergoing clinical trials. Also, novel lipid carrier-mediated vesicular systems are originated. This paper has focused on the lipid-based supramolecular vesicular carriers that are used in various drug delivery and drug targeting systems.