Drug eluting implants in pharmaceutical development and clinical practice

ABSTRACT

Introduction: Drug eluting implants offer patient convenience and improved compliance through less frequent dosing, eliminating repeated, painful injections and providing localized, site specific delivery with applications in contraception, ophthalmology, and oncology.

Areas covered: This review provides an overview of available implant products, design approaches, biodegradable and non-biodegradable polymeric materials, and fabrication techniques with a focus on commercial applications and industrial drug product development. Developing trends in the field, including expanded availability of suitable excipients, development of novel materials, scaled down manufacturing process, and a wider understanding of the implant development process are discussed and point to opportunities for differentiated drug eluting implant products.

Expert opinion: In the future, long-acting implants will be important clinical tools for prophylaxis and treatment of global health challenges, especially for infectious diseases, to reduce the cost and difficulty of treating chronic indications, and to prolong local delivery in difficult to administer parts of the body. These products will help improve patient safety, adherence, and comfort.

KEYWORDS:

• Drug-eluting
• implant
• long-acting
• parenteral
• sustained release

Article highlights

• Subcutaneous, drug-eluting implants have important benefits, particularly in improving patient compliance through less frequent dosing, eliminating repeated, painful injections and providing localized, site specific delivery

• Contraception, opthamology, and prostate cancer are three key indications where implants have had an effect on human health

• Three types of implants: matrix implants, reservoir implants, and osmotic implants have been developed, with different mechanisms of drug release

• The selection of an appropriate polymer is essential to implant design, with both biodegradable and non-biodegradable implants having been developed. Polymer chemical and thermal stability, safety, and processability should be considered in product design

• Polymer processing techniques of twin screw extrusion, single screw extrusion, and injection molding can be used to manufacture implants

This box summarizes key points contained in the article.

Declaration of interest

A Johnson, S Forster, G Terife, M Lowinger, and SE Barrett are employees of Merck & Co., Inc. D White is an employee of ExtruPharm, LLC and RS Teller is an employee of Abbott. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose

Additional information

Funding

This paper was not funded.