Design of an online-tuned model based compound controller for a fully automated artificial pancreas.

This paper deals with the development of a control algorithm that can predict optimal insulin doses without patients' intervention in fully automated artificial pancreas system. An online-tuned model based compound controller comprising an online-tuned internal model control (IMC) algorithm and an enhanced IMC (eIMC) algorithm along with a meal detection module is proposed. Volterra models, used to develop IMC and eIMC algorithms, are developed online using recursive least squares (RLS) filter. The time domain kernels, computed online using RLS filter, are converted into frequency domain to obtain Volterra transfer function (VTF). VTFs are used to develop both IMC and eIMC algorithms. The compound controller is designed in such a way that eIMC predicts insulin doses when the glucose rate increase detector of meal detection module is positive, otherwise conventional IMC takes the control action. Experimental results show that the compound controller performs robustly in the presence of higher and irregular amounts of meal disturbances at random times, very high actuator and sensor noises and also with the variation in insulin sensitivity. The combination of compound control strategy and meal detection module compensates the shortcomings of both slow subcutaneous insulin action that causes postprandial hyperglycemia, and delayed peak of action that causes hypoglycaemia. Graphical Abstract A fully-automated artificial pancreas system containing glucose sensor, insulin pump and control algorithm. Block diagram showing the control algorithm i.e., online-tuned compound IMC comprising enhanced IMC, conventional IMC and meal detection module, developed in the present work.

Novel drug delivery systems for ocular therapy: With special reference to liposomal ocular delivery.

Delivery of drugs to eyes is a great challenge to researchers because of a number of barriers in the eye preventing the actual dose from reaching the site. A number of ophthalmic delivery systems have been developed in the past couple of years that are not only new but also safe and reliable and help to overcome all those barriers in the eye which are responsible for the very less bioavailability of drugs. In this review, we tried to focus on current research in ocular delivery of drug substances giving special emphasis to liposomal delivery system. A brief analysis of other novel ocular delivery systems, ocular physiology, and microbial sources of disease are also highlighted herein. We analyzed the various research findings for churning a general idea for novel ocular delivery system and its future use. The novel formulations may overcome the addressed problems of ophthalmic medication and comply with the quality assurance issues. The liposomal delivery is advantageous as they have the ability to entrap both hydrophobic and hydrophilic drugs and are suitable for delivery to both the anterior and posterior segment of the eye. Therefore, the use of this alternative approach is quite a necessity.

Nano lipid-drug conjugate: An integrated review.

Lipid-drug conjugates (LDC), which may also be addressed as lipoidal prodrug, have the therapeutic actives chemically bound to a lipid moiety like fatty acids or phospholipids. Fabricated in nano-size, lipid-drug conjugate forms another breed of lipid nanoparticles. LDCs are prepared in order to increase the drug loading and hence prevent leakage of a highly polar drug from a lipophilic matrix. In turn, it assists to achieve active targeting of therapeutics with reduced side effect by altering the pharmacokinetic profile of the drug. These self-assembled systems take the benefit of metabolic pathways of lipid biochemistry, allowing suitable organ targeting depending upon its size. These lipids because of its similarities with physiological lipids, enhances the solubility of the therapeutic agents and thereby improve the bioavailability. This present review is meant to encompass different aspects related to lipid drug conjugates which include types of lipids and drugs that can be used to develop this type of formulation. Here, we throw light on methods of preparation of lipid drug conjugate, processing them into nanoparticle, its characterization and different applications of lipid drug conjugate. We aim to present a holistic view on lipid drug conjugate as a suitable drug delivery approach.