Preface

This book describes important information about drug delivery systems used for the treatment of various diseases. These systems improve the therapeutic effect of drugs either by targeting or delivering drugs at a specific rate to the desired site. The content of this book is useful for undergraduates and postgraduate students in sciences, pharmacy, and medicine as well as researchers and professionals familiar with the principles of drug delivery systems. The book focuses on unique drug delivery systems, strategy, technology, formulation-based approaches, and tailored systems established for the safe administration and within-body transportation of pharmaceuticals as needed for the greatest therapeutic advantages with the least amount of side effects possible. The introductory chapter on advanced drug delivery systems discusses conventional vs advanced drug delivery benefits. It also covers the various carrier systems used and approaches used in the last few decades.

Chapter 2, "Advances in Natural Polymeric Nanoparticles for the Drug Delivery", describes the key advantages of natural and biodegradable polymers in the development of various drug delivery systems. The complexity of diseases and the intrinsic drug toxicity and side effects have led to an interest in the development and optimization of drug delivery systems. The advancements in nanotechnology have favored the development of novel formulations that can modulate the biopharmaceutical properties of bioactives and thus improve their pharmacological and therapeutic action. The shape, size, and charge of nanoscale delivery systems, such as nanoparticles (NPs), are required to be investigated and changed to promote and optimize formulations. The various natural polymeric NPs (PNPs) are key for enhancing bioavailability or specific delivery to a certain site of action. This chapter describes the uses of various polymeric materials for the development of NPs as drug-delivery systems for various ailments. The entrapment of bioactive compounds in PNP systems is a hopeful move toward the improvement of the efficacy of drugs in the treatment of various diseases.

Chapter 3, "Recent Strategies for Ocular Drug Delivery: Promises and Challenges", discusses various systems to target the anterior and posterior segments of the eye. The unique anatomy and physiology of the eye lead to challenges in efficient ocular drug delivery. Nanoscience is emerging as an important tool in the development of novel strategies for ocular disease management. Various active molecules have been designed to associate with nanocarriers to overcome ocular barriers and interact with certain ocular tissues. This chapter examines barriers to intraocular delivery, general pathways for ocular absorption, and factors affecting intraocular bioavailability. It provides insight into such systems as nanomicelles, nanoparticles, nanosuspensions, vesicular systems, in situ gel, dendrimers, contact lenses, implants, microneedles, and cell-based delivery systems as well as gene-based ocular delivery systems.

Chapter 4, "Recent Pharmaceutical Developments in the Treatment of Cancer Using Nanosponges", discusses nanosponges, a class of nanoparticles characterized by their sponge-like surface that ensures high loading capacity in the treatment of cancer. The chapter discusses nanosponges and their synthesis, characterization, optimization, and applications in cancer. According to the literature, nanosponges can be classified based on their starting materials, which could be polymers, metals, or metal oxides, among other materials. Polymer nanosponges can be manufactured by methods such as the melt method, emulsion method, solvent method, and ultrasound-assisted method. Metallic nanosponges are manufactured by methods such as dealloying and sol–gel methods. Factors related to drugs or process parameters influence the formation of nanosponges. These process parameters have been used by many researchers to optimize the formulation of nanosponges to achieve optimum results related to loading efficiency, particle size, and encapsulation efficiency. Polymer structure also affects the formation of nanosponges. The chapter concludes with examples of using nanosponges for the delivery of anticancer drugs and current research trends.

Chapter 5, "Organogel: A Propitious Carman in Drug Delivery System", discusses the types, properties, synthesis/manufacturing, and applications of organogel. Types of organogels include lecithin organogels, pluronic lecithin organogels, limonene GP1/PG organogels, micro-emulsion based organogels (MBG) stabilized by gelatin, sorbitan organogels derived from fatty acids, polyethylene organogels, eudragit organogels, supramolecular organogels, and L-alanine-derived organogels. The chapter highlights the limitations of organogels as drug delivery systems. It describes various properties of organogels, including viscoelasticity, thermostability, thermoreversibility, non-birefringence, optical clarity, chirality effect, and biocompatibility. It also discusses the role of different organogelators like aryl cyclohexanol derivatives, polymer organogels, gemini organogelator, Boc-Ala(1)-Aib(2)-β-Ala(3)-OMe organogelators, and low-molecular weight organogelators (LMWOs) in formulating organogels. The chapter presents methods for the preparation of organogels such as the fluid-filled fiber method, solid fiber method, hydration method, and other novel methods. The chapter also explains factors affecting organogels, such as pH, temperature, moisture, type of organogelators, and moisture. Finally, it gives detailed applications of organogels in oral, topical, parenteral, and ocular drug delivery systems with suitable examples.

Chapter 6, "Transdermal Delivery of Drugs for Acute and Chronic Pain", discusses the application of transdermal drug delivery systems (TDDS) for the effective management of pain. The chapter explains the historical development of transdermal systems, key advantages and limitations, formulation composition/approaches, typical properties, and application of TDDS as carriers for drugs. It concludes that there are several patch options available on the market for the treatment of acute and chronic pain. TDDS is an attractive option because of its advantages over other systems (pills, tablets). It promotes pharmaceutical adhesion because it is a non-invasive method of dosage and self-administration. However, considerations must be made in diminishing the secondary and adverse effects of current TDDS and in combining new nanosystems for drug encapsulation for better control of the release. In future outlooks, new smart TDDS are being developed that include external stimuli for the release of the drug.

Chapter 7, "Mesoporous Silica Based Cancer Theranostic: A Modern Approach in Upcoming Medicine", explains the utilization of mesoporous silica micro/nanoparticles to load therapeutic and diagnostic agents for targeting cancer. The chapter discusses major challenges in targeting and treating cancer along with various diagnosis methods. It provides detailed information about nanoparticles as targeted drug delivery systems with special emphasis on mesoporous silica nanoparticles and their formulation, properties, biocompatibility, biodegradability, toxicity, and safety.

> **Bhupendra Prajapati** Shree S.K.Patel College of Pharmaceutical Education and Research, Ganpat University, Mahesana, India

**1**

**Chapter 1**

**1. Introduction**

Introductory Chapter: Advanced

"The process or method of providing a pharmaceutical substance to have a therapeutic effect in people or animals is known as drug delivery" [1]. A drug's compliance, safety, and efficacy can all be greatly enhanced by transforming it from its traditional form into a unique delivery system. An old drug molecule can be given new life with the use of an advance drug delivery system (ADDS). Various technological advances of unit operations such as drying, filtration, and mixing also help to advancement in modification and improvement in formulations [2]. With the right design, an ADDS can be a game-changer for addressing issues connected with targeted drug delivery. Pharmaceutical companies have been working on innovative drug delivery systems due to the growing demand for

The form in which a drug is administered can have a substantial impact on its efficacy. Some molecules have a range of optimal doses where the greatest benefit is obtained; dosages outside or inside of this range may be hazardous or have no therapeutic value at all [3]. The very gradual improvement in the effectiveness of treating serious diseases, on the other hand, has indicated an increasing need for a multidisciplinary approach to the delivery of medicines to target tissues. As a result, advanced methods for modifying pharmacological effects such as pharmacokinetics, pharmacodynamics, nonspecific toxicity, immunogenicity, biorecognition, and efficacy have been developed [4, 5]. Polymer science, pharmaceutics, bioconjugate chemistry, and molecular biology have all come together to form these advance techniques, which are collectively known as drug delivery systems [6, 7]. Various drug delivery and drug targeting approaches are being developed to limit drug breakdown and loss, reduce undesired side effects, enhance drug bioavailability and the proportion of drugs deposited in the appropriate location. What was once a fantasy or dream, controlled and advance drug delivery is now a reality. Over the past 15 years, researchers from pharmaceutical companies and other institutions have conducted exhaustive studies in this area of drug development. There are many different types of drug carriers, including soluble polymers, insoluble or biodegradable microparticles, natural and synthetic polymers, microcapsules, lipoproteins, liposomes, and micelles [7–10]. The carriers can be designed to break down slowly, respond to stimuli (such as pH or temperature), and be selectively delivered to their intended target (e.g., by conjugating them with specific antibodies against certain characteristic components of the area of interest). In order to deliver the drug to where it needs to go, you need to be able to "target" it. Two main approaches of targeting the sites of drug release: I. Non-active methods;

Drug Delivery Systems

safer, more effective methods of administering drugs to patients.

*Sankha Bhattacharya, Paul Rodriques* 

*and Bhupendra Prajapati*

## **Chapter 1**
