With an attendance of >2000 delegates, the 30th Annual Meeting of the Controlled Release Society (CRS) (Glasgow, UK, 19–23 July 2003; http://www.controlledrelease.org) addressed key issues in the formulation and targeting of molecules that are normally difficult to deliver. The Society’s major goal is to promote new technologies with which to achieve optimal plasma profiles of established and novel drugs. New drug delivery technologies enable drugs to be more effective and, therefore, have an important niche in treatments. Remarkably, drug delivery is still considered a poor relation to drug discovery; >95% of all new potential therapeutics have poor pharmacokinetics. The lack of promotion of drug delivery and controlled release was illustrated perfectly by the honest admission of a plenary speaker, Sir George Radda (former Head of the UK’s Medical Research Council), that he was unaware of the existence of the CRS before this conference. Rationale for controlled release Linda Hakes (Schwarz Biosciences, http://www.schwarzpharma.com/) presented an elegant set of arguments that addressed why we should continue to consider controlled release. Medicines need to be as effectively administered as possible to enhance compliance and efficacy. For example, drugs with short half-lives delivered by multiple injections or tablets each day are less attractive to patients than the same chemicals delivered by sustained release from a once-a-day oral formulation, a six-monthly implant or three-day skin patch. So much is the inconvenience, in fact, that efficacy is reduced because most patients tend to miss doses if required to adhere to complicated dosing regimes. Sustained plasma levels are typically preferred to the peak-and-trough plasma profile that is normally associated with oral and injected delivery. Furthermore, if the maximum plasma drug concentration (Cmax) is associated with side effects, then sustained release can improve the benefit:risk ratio. Hakes presented the potential advantages of a once-a-day transdermal patch containing a novel dopamine agonist for the treatment of Parkinsonism that is currently being developed by Schwarz. In this case, a sustained plasma profile from a once-a- day patch can offset the dyskinesia and rigidity that accompany the undulations in plasma levels that are produced by oral delivery. This example proves that a modified release formulation meets a real patient need and that the ‘ convenience’ argument promotes improved therapeutic efficacy. It is worth noting that Schwarz’s development approach (i.e. producing a transdermal formulation with a novel agent) is associated with a higher risk of adverse effects than are other approaches; all currently approved patches consist of pre- approved drugs. As justification, the laudable point was made that patients benefit more from optimization of a new drug formulation at the outset, rather than in later-generation products. From an economic viewpoint, such optimized formulations can lead to reduced hospital stays and additional savings to health services. Oral delivery: linking biology to formulation Of the 100 top-selling drugs in America, 76 are available as oral formulations. There is no doubt that the oral route is preferred by patients and that it still dominates controlled release research. From a personal review of 30 years of delivery research, Bob Davis (University of Nottingham; http://www.nottingham.ac.uk) presented some highlights that have had a major impact on this field. He asserted that advances are made when formulation and cell biology or gut physiology are studied in parallel. In the 1970s, little was known about processing times in different regions gastrointestinal (GI) tract. Pioneering the technique of gamma scintigraphy, Davis ’ group concluded that transit time in the colon could be upto 20 hours and could, therefore, be a potentially attractive delivery site for drugs. This spawned the field of colonic targeting using biodegradable particles, azo-polymer prodrugs, chitosan bioadhesives and pH-sensitive coatings. Gamma scintigraphy underpinned the establishment of Pharmaceutical Profiles (Nottingham, UK), a company specialising in tracking the movement of devices and formulations along the human GI tract. update conference DDT Vol. 8, No. 21 November 2003 1359-6446/03/$ – see front matter ©2003 Elsevier Science Ltd. All rights reserved. PII: S1359-6446(03)02874-5 976 www.drugdiscoverytoday.com Controlled release technologies for drug delivery David J. Brayden, Faculty of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland; tel: +3531 7166013, email: david.brayden@ucd.ie