Programmed drug release

R.P. Scherer Corporation, MI, USA Pulsincap system A unique CR (capsule) device that permits programmed drug release at a predetermined time and/or site within the GI tract (e.g., colon). Allows sequential dosing of a patient at different predetermined times and/or sites in the GI tract, with same or different drugs. Under development. 

Grolleman, C. W. J. et al. Polyphosphazenes as a system for programmed drug release, in Proceedings of the Int. Conf Biomedical Polymers, p. 203, London, The Biological Engineering Society 1982... 

Ideally, the release of an ionizable compound from a sustained-release product should be programmed in accordance with the variation in physiological pH along different segments of the Gl tract. Thus, theoretically, the amount of the absorbed (uncharged) species and the plasma concentration can be kept approximately constant throughout the time course of drug release and action. 

The requirement that drugs be both effective and safe did not become law until 1962. The Kefauver-Harris amendment to the Food, Drug, and Cosmetic Act passed in 1962 required the FDA to review all drugs released after 1938 for effectiveness as well as safety. This program established the Drug Efficacy Study Implementation (DESI) and the job was assigned to the National Academy of Sciences—National Research Council, which reviewed the data presented for each drug that had been submitted to the FDA. 

Time-controlled systems. These systems rely on the relatively consistent small intestinal transit time, which approximates between 3 and 5h. Obviously, drug release from such systems occurs after a predetermined lag phase (i.e., >5h), which can be precisely programmed by adjusting the thickness and/or composition of the barrier (e.g., coating) formulation. Examples... 

Yuzhakov et al. [93] describe the production of an intracutaneous microneedle array and provide an account of its use (microfabrication technology). Various embodiments of this invention can include a microneedle array as part of a closed loop system smart patch to control drug delivery based on feedback information from analysis of body fluids. Dual purpose hollow microneedle systems for transdermal delivery and extraction which can be coupled with electrotransport methods are also described by Trautman et al. [91] and Allen et al. [100]. These mechanical microdevices which interface with electronics in order to achieve a programmed or controlled drug release are referred to as microelectromechanical systems (MEMS) devices. 

Keywords Ceric ammonium nitrate, controlled drug release, flocculation, microwave assisted grafting, molecular programming, polysaccharide, SEM, intrinsic viscosity, rheology, drug delivery system... 

Step 4 Drug release patfem and degradation behavior including mechanical properties and the Influence of a cycle consisting of programming and recovery on dmg release. 

Fig. 9 Drug release from oLG tetrole derived SMP in phosphate buffer pH 7 at 37°C. (a) Cumulative release of well soluble ethacridme lactate (EL) tmd less soluble enoxadne (EN) and nitioluiantom (NF). (b) Release rates of EL from the permement shape = 0%) and the slowly recovering program mcd shape = 130%). Reprinted from [30]. Copyright 2009, with peimission from Elsevier...

Maleki, M., Amani-Tehran, M., Latifi, M., Mathur, S., 2014. Drug release profile in core—shell nanofibrous structures a study on Peppas equation and artificial neural network modeling. Computer Methods and Programs in Biomedicine 113, 92—100. 

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