The central nervous system (CNS) is being protected by the blood-brain barrier (BBB) for efficiently maintaining the homeostasis. The BBB not only restricts the entrance of harmful endogenous and xenobiotic molecules but also restricts the entrance of therapeutic agents. The motif of a carrier or a drug that effectively overcomes the restraints imposed by the BBB needs compatibility with this main biological barrier. Understanding the physicochemical features of the carrier or drug and how it interacts with BBB is vital for effective brain delivery. Ever since less than 5% of the established molecules can cross the BBB. Nanotechnology has the potential and provides infinite possibilities to deliver therapeutic agents for various disorders of the CNS across BBB. Numerous drug delivery systems (DDSs) have been developed that demonstrate exceptional potential in therapeutic agent delivery to CNS while exhibiting marginal side effects. Recently, due to exceptional surface electrostatics, functional versatility, and excellent biocompatibility properties nano-diamonds are also being investigated for their drug delivery capability to the CNS. Moreover, modifications or functionalization of the nanocarriers with specific targeting ligands or molecules has demonstrated remarkable results for effective delivery of drugs to the CNS through receptor-mediated transcytosis. The current chapter presents a comprehensive understanding of the developments made in nanocarriers for effective drug delivery to the CNS.

Bone tissues defects are currently causing an increased burden on healthcare systems around the world. Current bone tissue engineering methods face challenges such as ineffective cell growth, a lack of appropriate biomaterials, and techniques for capturing appropriate physiological architectures, as well as insufficient and unstable growth factor production to stimulate cell communication and proper response. Nanomaterials at the cutting edge of nanotechnology, with their unique size-dependent characteristics, have shown promise in overcoming many of the challenges that bone tissues engineering faces today. The previous and current advances in bone tissue therapies based on nanotechnological techniques are discussed in this chapter. Nonotherapeutic strategies for delivering drugs and growth factors that promote bone development, as well as gene therapy materials, are among the most notable. Nanomaterials have also made significant progress in stem cell targeting and imaging, which will be described. Finally, current developments in nano-composite construction and scaffold adaptations will be discussed to increase our understanding of the biocompatibility, cellular survival, and mechanical stability of implanted constructs.

The efficient drug cargo to the heart and other relevant target sites is a key strategy for treatment of several cardiovascular disorders. Nanotechnology has got increased attention for delivering therapeutic agents and manifested an immense potential in the design of nanocarriers-based drug delivery systems. Heart-targeted nanocarriers-based drug delivery is an emerging, efficacious and effective strategy for treating a number of cardiac disorders including arrhythmias, atherosclerosis, thrombosis, myocardial infarction, ischemic heart diseases, and related complications. Nanocarriers-based delivery systems overcome the problems of severe side effects, nonspecificity, and normal cells’ damage that are associated with conventional approaches of delivering drugs. Moreover, the easy modification of physicochemical characteristics of nanocarriers, e.g., shape, size, and surface chemistry can greatly alter the in-vivo pharmacokinetics and pharmacodynamics of the encapsulated drugs that could provide better and improved treatment outcomes. Various drug delivery systems based on lipids, phospholipids, and polymers have been constructed for targeted delivery of drugs within the heart. The goal of this chapter is to provide an overview of the variety of nano-structures’ based carriers employed in delivering drugs for the successful treatment of a variety of cardiovascular ailments. Liposomes, dendrimers, polymer-drug conjugates, micelles lipid nanoparticles, nanostents, nanoburrs, microparticles, nanoparticles, and microbubbles are only a few of the many nanoscale drug delivery structures that have been discussed in detail.

Transdermal drug delivery system (TDDS) has an immense importance in the treatment of skin diseases and skin lesions because it reduces the adverse effects associated with systemic delivery. However, transdermal delivery is challenging due to the natural protective barrier of the skin that limits the permeation of drug molecules across the skin. Therefore, several strategies have been adopted to enhance the permeation of drugs and bioactive molecules through the skin. This chapter encompasses the advancement of engineered technologies in TDDS including sonophoresis, iontophoresis, electroporation, microneedle, nanoparticulate, and vesicular systems. In addition, these technologies in combination have been studied for synergistic effects and to enhance the physiochemical properties of drugs and the delivery carriers to treat various skin diseases (including acne, psoriasis, wounds, melanoma, etc.). These above-mentioned systems are overviewed in detail and they enlighten several methods to improve skin-related diseases.

The concept of novel strategies for the development of nanocarriers-based drugs has rapidly emerged over the last few decades. In fact, nanocarriers could be successfully employed as drug delivery tools due to their optimized biological and physicochemical properties and a wide range of practical applications in the field of medicines. Numerous critical issues of conventional drug delivery systems including drug resistance, poor water solubility, drug toxicity, poor specificity and low bioavailability are potentially associated with the decreased therapeutic potentiality of various drug systems. On the contrary, nanocarrier-based systems consisting of colloidal nanoparticles offer more advantages in terms of active drug transportation due to the high surface area to volume ratio. The ultimate goal of nanocarriers’ employment in drug delivery systems is to achieve the desired therapeutic outcomes by maximizing drug efficacy and minimizing its side effects during the course of treating a particular disease. In this chapter, various types of nanocarriers, their properties and drug delivery applications have been discussed in detail. Moreover, the gastrointestinal absorption and the drug release mechanisms from nanocarriers have also been elucidated.

Oral administration of drugs is the most preferred route even though it faces some critical challenges such as off-target drug distribution causing un-desirable side effects and getting less effective delivery of the drug. The main barriers for therapeutic agents in oral drug administration are its extensive and variable pre-systemic metabolism, vulnerability to gastrointestinal (GI) tract environment, and enzymatic degradation leading to erratic and inadequate bioavailability, and low absorption. To meet these challenges, nanotechnology owes the potential to provide infinite possibilities for enhancing drug absorption through the GI tract. Numerous drug delivery systems (DDSs) have been developed that demonstrate exceptional potentials in therapeutic agents’ delivery for treating different diseases while exhibiting marginal side effects and minimizing toxicity to other tissues of the body. Formulation in nanocarriers can reduce the susceptibility of drugs in the GI tract environment, improve drug solubility and absorption, provide protection against enzymatic degradation, and offer controlled release in the GI tract. Moreover, modifications or functionalization of the nanocarriers with specific targeting ligands or molecules has demonstrated remarkable results for effective delivery and enhanced absorption through the GI tract. However, the diverse physiology of the GI tract in different sections such as variation in pH, different cell types, variation in structure and thickness of the mucus, and numerous physiological functions act as the barriers to effective drug delivery and provide an opportunity for designing and developing of novel nanocarriers. The current chapter presents a comprehensive understanding of the developments made in nanocarriers based on enhancing drug absorption through the GI tract.

Drug delivery through pulmonary route has gained great momentum in recent years. The extensive vascularization, thin epithelial barrier, and vast surface area of nearly 100m2 of alveoli augment drug uptake and transport. This route of drug delivery would significantly ease treatment of lungs diseases like Cystic fibrosis and Tuberculosis. The systemic adverse effects of drugs might also be decreased by directly delivering the drug to its desired site of action. Nanotechnology-based drugs or nano-medicines have greater potential for treatment of ailments via targeted delivery of drugs. Synthesis of specific particles for certain population of cells or organs like respiratory tract targeting is possible with exploitation of particle's characteristics, e.g., surface chemistry, size, surface area, and surface charge. Particularly, pulmonary drug delivery is currently being extensively investigated using nanometer size ranged particles (nanoparticles having 300nm or less mean diameter) and it is speculated that in near future, lungs diseases may be efficiently and effectively treated through drug-loaded inhalable nanocarriers. This strategy might enhance therapeutic effects of the drugs and reduce their systemic adverse effects. The toxicological aspects of nanocarriers must also be considered subsequent to their application as favorable avenue for pulmonary drug delivery. Hence it will be possible to minimize and control such detrimental/toxic effects by identification of various modes of nanocarriers’ interactions thus will allow nanocarriers to be used safely as therapeutic agents for site-specific and targeted drug delivery.

Over the last two decades, scientists have faced a significant challenge in designing and developing new drug delivery systems capable of overcoming ocular barriers for the treatment of a variety of disorders affecting the front and posterior parts of the eye. Nanotechnology-based ophthalmic drug delivery techniques are novel techniques that can increase the pharmacological activity of drugs by enhancing the concentration and bioavailability of therapeutic agents in targeted tissues. To surpass the ocular barriers and improve the ocular bioavailability of pharmacologically active compounds toward the ocular tissues, different conventional and novel drug delivery systems have been developed including ointments, emulsion, aqueous gels, suspensions, nanoparticles, liposomes, nanomicelles, contact lenses, dendrimers, and in situ thermoresponsive hydrogels. This chapter summarizes and reviews current conventional ophthalmic formulations and their advancement, as well as the development and innovation of nanotechnology-based formulations for the treatment of ocular diseases. It also provides an overview of recent developments in the field of nanocarrier-based ophthalmic drug delivery strategies.

The treatment and management of renal disorders have currently caused a huge global burden. Targeted delivery of therapeutic agents to renal tissues has been a challenging task due to the peculiar physiology and functions of the kidneys. Recent advances in targeted nanotherapies have been used to boost therapeutic efficacy while reducing off-target negative effects. Various types of targeted nanocarriers have been developed to help treat renal disorders with targeted delivery of therapeutic agents. Although the use of targeted nanocarriers in the treatment of renal disorders is still in its early phases, it offers a lot of potential. A growing number of targeted nanocarriers based drug delivery systems are being used to treat renal disorders. This chapter reviews the current developments in targeted nano drug delivery systems that have been developed to treat a variety of renal disorders. The chapter will increase our understanding of different targets that can be effectively utilized for targeted delivery of drugs for the treatment and management of different renal disorders.

Liver is the key organ in human body responsible for numerous functions including protein synthesis, detoxification, and the production of necessary biochemicals for life sustenance. Viral hepatitis, liver cirrhosis, and hepatocellular carcinoma are some of the chronic liver diseases that need immediate attention for sustainable life of patients with such chronic liver diseases. Among these diseases, Hepatocellular carcinoma (HCC) is the most common one with high mortality and morbidity rates. The requirement of having multiple nanocarriers and active agents for improved therapy, imaging, and controlled release of medications in one platform has made the construction of therapeutic and theranostic nanodrug delivery systems a difficult challenge for contemporary researchers. Multiple drug resistance (MDR), high clearance rate, severe side effects, undesirable drug distribution to the non-specific liver sites, and low concentration of drug that reaches liver cancer cells are just a few of the drawbacks of traditional liver cancer chemotherapy. Thus, new techniques and nanocarriers need to be developed for efficient transport of drugs to malignant hepatocytes in an acceptable concentration and for sufficient duration inside the therapeutic window. Because of the great efficacy of drug loading or drug encapsulation efficiency, high cellular uptake, high drug release, and minimal adverse effects, nanocarriers’ based systems offer benefits over conventional chemotherapy. These nanocarriers have a high drug accumulation rate in tumors while causing minimal toxicity in healthy tissues. This chapter focuses on nanocarrier-based drug delivery systems for targeted liver cancer therapy with special focus on HCC and clinical advancements of therapeutic nanocarriers for liver cancer.