Advances in Drug Delivery

The main aim in the drug therapy of any disease is 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 drug 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 targeting means delivery of the drug-loaded system to the site of interest. Drug carrier systems include polymers, micelles, microcapsules, liposomes and lipoproteins to name some. Different polymer carriers exert different effects on drug delivery. Synthetic polymers are usually non-biocompatible, non-biodegradable and expensive. Natural polymers such as chitin and chitosan are devoid of such problems. Chitosan comes from the deacetylation of chitin, a natural biopolymer originating from crustacean shells. Chitosan is a biocompatible, biodegradable, and nontoxic natural polymer with excellent film-forming ability. Being of cationic character, chitosan is able to react with polyanions giving rise to polyelectrolyte complexes. Hence chitosan has become a promising natural polymer for the preparation of microspheres/nanospheres and microcapsules. The techniques employed to microencapsulate with chitosan include ionotropic gelation, spray drying, emulsion phase separation, simple and complex coacervation. This review focuses on the preparation, characterization of chitosan microspheres and their role in novel drug delivery systems.

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.

Buccal films are sophisticated mucoadhesive dosage forms designed to administer therapeutic agents through the buccal mucosa. The field of buccal film research and development has progressed substantially, with numerous studies examining various polymers, drug candidates, and formulations. Compared to traditional oral dosage forms, polymer-based buccal films present several advantages, such as ease of administration, enhanced patient compliance, and the potential for targeted drug delivery. The examination of both natural and synthetic polymers in the creation of buccal films has resulted in a wide variety of formulations, each with distinct characteristics and performance metrics. The choice of suitable polymers is crucial, as it influences the mechanical properties of the films, drug release kinetics, and overall biocompatibility. Natural polymers, sourced from renewable materials, boast inherent biocompatibility and biodegradability, rendering them appealing options for buccal film development. On the other hand, synthetic polymers afford greater control over material properties and can be specifically engineered to achieve targeted drug release profiles. While, smart polymer buccal films represent a sophisticated approach to drug delivery by incorporating stimuli-responsive polymers with strong mucoadhesive characteristics, enabling the regulated release of medication via the buccal mucosa. This review also provided a thorough understanding of the advantages and limitations associated with both natural, synthetic and smart polymers, which is vital for the rational design of effective buccal film formulations. The required properties of the polymeric buccal films such as mucoadhesion, folding endurance and permeability as drug carrier are also discussed by summarizing the findings from the previous research works, highlighting the importance of these aspects for future development of the polymeric based buccal film with great performance. The constraints of the buccal films developed to date, as well as their possible avenues for future improvement, have been examined.

<p><strong><span lang="IN">ABSTRACT. </span></strong><span>Polymers have become essential excipients in pharmaceutical formulations, significantly enhancing drug delivery systems due to their versatility, biocompatibility, and specialized properties. This review discusses the role of natural and synthetic polymers, which are favored for their biodegradability and ability to improve drug stability and controlled release. The paper highlights innovations in polymer-based drug delivery, including the development of stimuli-responsive polymers that release drugs in response to specific environmental triggers and the integration of natural and synthetic polymers to create hybrid systems. Despite the advantages, challenges such as variability in natural polymer sources, potential toxicity of synthetic polymers, and regulatory hurdles remain. Future prospects include advancements in green and sustainable polymers, personalized medicine, and the use of nanotechnology to enhance drug delivery efficacy. This comprehensive examination underscores the importance of interdisciplinary research in overcoming existing barriers and advancing polymer-based drug delivery systems to improve patient outcomes. </span></p><p><strong>Keywords:</strong></p><p align="left">Polymer, Drug delivery, Natural polymer, Synthetic polymer, Stimuli-responsive</p><p><span><br /></span></p>

ABSTRACTIntroduction: Natural pharmaceutical excipients have been applied extensively in the past decades owing to their safety and biocompatibility. Zein, a natural protein of plant origin offers great benefit over other synthetic polymers used in controlled drug and biomedical delivery systems. It was used in a variety of medical fields including pharmaceutical and biomedical drug targeting, vaccine, tissue engineering, and gene delivery. Being biodegradable and biocompatible, the current review focuses on the history and the medical application of zein as an attractive still promising biopolymer.Areas covered: The current review gives a broadscope on zein as a still promising protein excipient in different fields. Zein- based drug and biomedical delivery systems are discussed with special focus on current and potential application in controlled drug delivery systems, and tissue engineering.Expert opinion: Zein as a protein of natural origin can still be considered a promising polymer in the field of drug delivery systems as well as in tissue engineering. Although different researchers spotted light on zein application in different industrial fields extensively, the feasibility of its use in the field of drug delivery replenished by investigators in recent years has not yet been fully approached.

Microparticle delivery system is accepted as are reliable. Mean to delivery the drug to the target site with specificity,. The drug should be delivered to specific target site at a rate and concentration that provides optimum therapeutic efficacy and reducing the side effect to minimum. Microspheres are empty spherical particles, the particle size is less than 200 mm. Microspheres are free flowing powder consisting of natural and synthetic polymers. They have the potential controlled release drug. Polymers are the most important things of pharmaceutical drug delivery. There are many kind of polymers which varying the properties available those days for use in different pharmaceutical applications. Polymers use in the preparation of microspheres is the synthetic and natural polymers. Synthetic polymers are acrolein, poly anhydrides, methyl meth acrylate, lactides, and glycosides. Natural polymers are albumin, gelatin, collagen, agarose, chitosan, carragenene. Microspheres are the free flowing powders consist of protein and synthetic polymers having a particle size ranging from 1 ? 1000 micrometer. Microspheres are prepared by several techniques but the choice of method depends upon the drug. The polymers used and duration of action required. The evaluation parameters of microspheres are micromeritic properties particle size and shape, swelling index, tapped density, drug loading efficiency. In coming days by combining numerous other sceniorio, we will find the microspheres in novel drug delivery. Specifically in disease cell sorting diagnostics, gene and genetic materials, safe targeted and effective in vivo delivery and supplements a tiny interpretation of diseased organ and tissue in the body. Keywords: Microencapsulation, novel drug delivery, synthetic and natural polymers, duration of action.

Owing to the importance of drug delivery in cancer or other diseases’ therapy, the targeted drug delivery (TDD) system has been attracting enormous interest. Herein, we model the TDD system and design a novel rod-like nanocarrier by using the coarse grained model-based density functional theory, which combines a modified fundamental measure theory for the excluded-volume effects, Wertheim’s first-order thermodynamics perturbation theory for the chain connectivity and the mean field approximation for van der Waals attraction. For comparison, the monomer nanocarrier TDD system and the no nanocarrier one are also investigated. The results indicate that the drug delivery capacity of rod-like nanocarriers is about 62 times that of the no nanocarrier one, and about 6 times that of the monomer nanocarriers. The reason is that the rod-like nanocarriers would self-assemble into the smectic phase perpendicular to the membrane surface. It is the self-assembly of the rod-like nanocarriers that yields the driving force for the targeted delivery of drugs inside the cell membrane. By contrast, the conventional monomer nanocarrier drug delivery system lacks the driving force to deliver the drugs into the cell membrane. In short, the novel rod-like nanocarrier TDD system may improve the drug delivery efficiency. Although the model in this work is simple, it is expected that the system may provide a new perspective for cancer targeted therapy.

Crossing Barriers From blood-to-brain and academia-to-industry

Bioactive polymers, by their structural configuration and conformation, possess the ability to exert biological activities and consequently elicit responses from cells and tissues. Intelligent polymers are smart polymers which respond to internal and external stimuli in order to propel the release or modify the release of drugs. Natural polymers are biogenic, biocompatible, biodegradable, and safe for consumption. Consequently, they present as suitable materials that the human body can identify with and not treat as foreign bodies, thereby reducing the complications encountered when dealing with synthetic polymers. Natural polymers have been shown to be bioactive, exhibiting biological activities such as antitumor, anticoagulant, antioxidant, antimicrobial, antiulcer, anti-inflammatory, and antirheumatic. In addition, natural polymers are meritorious materials for the fabrication of self-regulated or externally regulated drug delivery systems. These systems respond to the state of the environment for efficacious therapy. Drug delivery technology is shifting from the controlled release of drugs over time to the release of drugs when and where needed, especially for chronic diseases. Indeed, intelligent polymers are choice polymers for such delivery systems. Their synthetic counterparts were actually synthesized to mimic these natural polymers which further buttress the need to revert to nature for intelligent and bioactive polymers. The contexts of natural bioactive and intelligent polymers have unique applications in drug delivery, embracing nanobiotechnology. This would ultimately benefit drug delivery systems in benchmarking new drug formulations.

Targeted drug delivery systems have emerged as promising approaches for improving the efficacy and safety of cancer therapy. This review highlights recent advancements in drug delivery technologies aimed at achieving targeted and personalized treatment strategies for cancer patients. The integration of nanotechnology, biomaterials, and molecular targeting strategies has enabled the development of sophisticated drug delivery systems capable of selectively delivering therapeutic agents to tumour tissues while minimizing off-target effects on healthy tissues. Various targeting mechanisms, including passive and active targeting strategies, exploit the unique physiological characteristics of tumours, such as abnormal vasculature, overexpressed receptors, and altered microenvironments, to achieve selective accumulation and retention of drugs within tumour tissues. Nanoparticle-based drug delivery systems, such as liposomes, polymeric nanoparticles, and inorganic nanoparticles, offer advantages in terms of drug loading capacity, sustained release, and tumour targeting, making them attractive platforms for targeted cancer therapy. Moreover, the integration of smart drug delivery systems that respond to specific stimuli within the tumor microenvironment, such as pH, temperature, or enzyme activity, holds promise for enhancing tumor specificity and reducing systemic toxicity. Combination therapy approaches, which combine targeted drug delivery with other therapeutic modalities, such as immunotherapy or photodynamic therapy, offer synergistic effects and opportunities for overcoming treatment resistance. Despite these advancements, several challenges remain, including the translation of preclinical research findings into clinically viable therapies, regulatory approval, manufacturing scalability, and biomarker discovery. Addressing these challenges and embracing innovative approaches will be essential for realizing the full potential of targeted drug delivery systems in improving patient outcomes and advancing cancer therapy.

MODERN STATE OF CREATION, PRODUCTION AND RESEARCH OF DRUGS

Polymers are playing an important role in the designing of both conventional and novel drug delivery systems. It can be capable to modify the drug-release pattern, increase the stability of the drug and modify the pharmacokinetic properties of the drug. Polymers occupy a major portion of materials used for the fabrication of drug-targetable and controlled-release formulations because it presents seemingly endless diversity in topology and chemistry, which offers easy functionalisation on them. Most of the natural and synthetic biodegradable polymers have some specific properties such as degradability, adhesiveness, non-immunogenicity, non-inflammatory and non-toxicity as well as provide the significant advantage of being able to be broken down and removed after they have served their function. Some natural polymers also have anticancer, antidiabetic and other therapeutic properties. Biodegradable polymers are widely used in the designing of both conventional and novel drug delivery systems. They are used as binders, disintegrating agent, to mask the unpleasant taste of therapeutics in the pharmaceutical industry. The polymers that show pH, temperature and ion responsive drug-release properties may help to make its drug delivery system, targetable or site-specific, and protect from a specific enzymatic and pH environment. The designing of copolymers offers high drug loading capacity for both polar and non-polar drugs and high functionalisation. This entry includes different types of natural and synthetic biodegradable polymers with specific physicochemical and biological properties along with their use in the designing of conventional and novel drug delivery systems.

Natural and synthetic polymers have been used in pharmaceutical industry for many years and have important role in the development of the conventional dosage forms or for manufacturing of various drug packaging materials. In recent years, their important application resides in the development of the most sophisticated drug delivery systems where polymers are used as a drug carrier. Biodegradable polymers are particularly attractive for application in drug delivery systems since, once introduced into the human body, they do not require removal or additional manipulation. Their degradation products are normal metabolites of the body or products that can be metabolized and easily cleared from the body. Among that, synthetic polymers offer a wide variety of compositions with adjustable properties. These materials open the possibility of developing new drug delivery systems with specific properties (chemical, interfacial, mechanical and biological) for a given application, simply by changing the building blocks or the preparation technique. Such designed complex drug delivery systems where polymers are used as functional excipients have numerous advantages such as localized delivery of drug, sustained delivery of drug, stabilization of the drug, prevention of drug’s adverse side-effects, reduction of dosing frequency, minimization of drug concentration fluctuations in plasma level, improved drug utilization and patient compliance. There are range of differently designed drug delivery systems and their description and mechanism of action will be presented in this paper together with the prominent role of the polymers for each particular system. Additionally, most commonly used synthetic biodegradable polymers in drug delivery systems will be presented together with their degradation mechanism.

Polymers, both synthetic and natural, play a critical role in modern drug delivery systems by enhancing the efficacy, targeting, and release profiles of therapeutic agents. This comprehensive review delves into the various types of synthetic polymers such as poly (lactic-co-glycolic acid) (PLGA), polyethylene glycol (PEG), and polyvinyl alcohol (PVA), as well as natural polymers like chitosan, alginate, and gelatin. These polymers are explored for their potential to improve solubility, bioavailability, and controlled release of drugs. Moreover, their application in targeted drug delivery, particularly for cancer, cardiovascular, and inflammatory diseases, is highlighted. The review also compares the advantages and limitations of synthetic versus natural polymers, discussing their biodegradability, biocompatibility, and regulatory considerations. Advances in polymer-based drug delivery platforms such as nanoparticles, hydrogels, and micelles are also examined, offering insights into future directions in personalized medicine. The highlights of provide in the review article, initially basics of drug delivery, polymer, polymerization with role of polymer in polymerization. At intermediate, classification, sources of polymer with that some advanced approached in drug delivery and lastly, marketed, recent available products with future challenges and current status in the drug delivery. Keywords: Biodegradable polymer; natural; compatible; drug delivery; treatment; enhancing; polymers.

Chapter 8 - Polymer-based nanoparticles as delivery systems for treatment and vaccination of tuberculosis