Drug Delivery

FORMULATION FORUM - Advances in Drug Delivery by Antibody Drug Conjugates (ADCs)

Shaukat Ali, PhD, and Jim Huang, PhD, focus on two aspects of drug delivery through ADCs. One, where an antibody is conjugated via a ligand with functionalized LNPs carrying cytotoxic drugs; and two, where an antibody is conjugated directly with drug through a linker at the specific site.

What are Drug Delivery Systems?

Drug delivery systems are engineered technologies for the targeted delivery and/or controlled release of therapeutic agents. The practice of drug delivery has changed significantly in the past few decades and even greater changes are anticipated in the near future. Drug delivery includes but is not limited to oral delivery, gene/cell delivery, topical/transdermal delivery, inhalation deliver, parenteral delivery, respiratory delivery, capsules, particle design technology, buccal delivery, etc.

The Evolution of Drug Delivery Systems

Drug delivery systems have greatly evolved over the past 6 decades. In the past 12 years specifically, there have been huge advancements in drug delivery technology. For instance, advanced medication delivery systems, such as transdermal patches, are able to deliver a drug more selectively to a specific site, which frequently leads to easier, more accurate, and less dosing overall. Devices such as these can also lead to a drug absorption that is more consistent with the site and mechanism of action. There are other drug delivery systems used in both medical and homecare settings that were developed because of various patient needs and researchers continue to develop new methods.

Drug Delivery System Market Size

The pharmaceutical drug delivery market size is studied on the basis of route of administration, application, and region to provide a detailed assessment of the market. On the basis of route of administration, it is segmented into oral delivery, pulmonary delivery, injectable delivery, nasal delivery, ocular delivery, topical delivery, and others.

The estimated global market size of drug delivery products was $1.4 trillion in 2020. Unfortunately, 40% of marketed drugs and 90% of pipeline drugs (mostly small molecules) are poorly soluble in water, which makes parenteral, topical, and oral de­livery difficult or impossible. In relation, poor solubility often leads to low drug efficacy. Add in the fact that many other hurdles exist in the form of drug loading, stability, controlled release, toxicity, and absorption – it’s not hard to understand the difficulties in bringing new drug products to market. Additionally, biopharma­ceuticals (proteins, peptides, nucleic acids, etc) and combination drug products possess many of these same problematic obstacles that affect efficacy. These challenges, coupled with the complexity and diversity of new pharmaceuticals, have fueled the develop­ment of a novel drug delivery platforms that overcome a great many bioavailability and delivery obsta­cles. By leveraging these platforms, pharmaceutical and biopharmaceutical companies can improve dosing accuracy, efficacy, and reproducibility in their drug discovery and drug delivery research.

Drug Delivery System Demand

The demand for pharmaceutical products worldwide is only going to increase in the coming years, as old and emerging dis­eases continue to threaten the well-being of people globally. Drug discovery efforts are expected to intensify, generating a large va­riety of active compounds with vastly different structures and properties. However, it is well known that despite tremendous out­put of the drug discovery process, the success rate of a candidate compound becoming an approved drug product is extremely low. The majority of candidate compounds are discarded due to var­ious hurdles in formulation and preclinical testing (such as issues with solubility, stability, manufacturing, storage, and bioavailabil­ity) before even entering into clinical studies. Therefore, advances in formulation and drug delivery, especially the development of new and versatile biomaterial platforms as effective excipients, may salvage many “difficult,” otherwise triaged, drug com­pounds, and significantly enhance their chance of becoming vi­able products. Furthermore, breakthroughs in biomaterial platform technologies will also facilitate life cycle management of existing APIs through reformulation, repurposing of existing APIs for new indications, and development of combination prod­ucts consisting of multiple APIs.