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Diagnostic Approach to Acute Kidney Injury in the Critical Care Unit
Published in Cheston B. Cunha, Burke A. Cunha, Infectious Diseases and Antimicrobial Stewardship in Critical Care Medicine, 2020
Sonali Gupta, Divyansh Bajaj, Sana Idrees, Joseph Mattana
The gradual removal of solute, water, and electrolytes, offered by CRRT, may make it the preferred therapy in certain circumstances where the patient is more susceptible to volume and osmotic/metabolic fluctuations. It may offer better hemodynamic and volume homeostasis in hemodynamically unstable patients with considerable volume overload and is generally a preferable option in patients with acute brain or liver injury, where rapid shifts in blood osmolality may contribute to an iatrogenic increase in intracranial pressure. The CRRT is also recommended in situations where extracorporeal life support therapies are applied. It can be performed using diffusive clearance (continuous venovenous hemodialysis [CVVHD]), convective clearance (continuous venovenous hemofiltration [CVVH]), or a combination of both (continuous venovenous hemodiafiltration [CVVHDF]). Although convective modalities offer greater clearance of middle molecules compared with diffusive clearance, this has not been shown to affect clinical outcomes in the AKI setting, and the choice between modalities should be determined by local expertise. A comparison of RRT modalities is provided in Table 24.5.
Oxidative Properties of the Skin: A Determinant for Nickel Diffusion
Published in Jurij J. Hostýnek, Howard I. Maibach, Nickel and the Skin, 2019
Jurij J. Hostýnek, Katherine E. Reagan, Howard I. Maibach
Values for the main components of sweat have repeatedly been investigated over time, yielding increasingly accurate data reflecting improvements in analytical techniques. The main categories of solutes are discussed here. Table 3.1 lists the prevalent ranges; they are approximations, because values are unavoidably subject to variation even in normal subjects due to the type of stress applied for sweat stimulation, environmental and individual temperature, environmental humidity, diet and nutritional status, age, gender, sweat rate, skin area of collection, local skin temperature, and muscular activity.
Heart Microcirculation
Published in John H. Barker, Gary L. Anderson, Michael D. Menger, Clinically Applied Microcirculation Research, 2019
An important feature of this approach is that the hemodynamic and exchange properties of coronary microvessels can be studied at precisely controlled conditions. The preparation enables rapid and repeated measurements. Because intraluminal pressure and flow are independently controlled, and because extrinsic factors including vasoactive agents and permeability-influencing factors are eliminated, the technique allows direct evaluation of the effects of blood components and chemical mediators on solute exchange. For example, inflammatory mediators have been implicated to increase venular solute exchange, not only by their direct effects on the vessel wall but also by the indirect effects through altering microvascular pressure and activating neutrophils, which in turn cause venular hyperpermeability.17 With this experimental model, the direct and indirect effects of these factors can be systemically evaluated.48
Desmopressin acetate the first sublingual tablet to treat nocturia due to nocturnal polyuria
Published in Expert Review of Clinical Pharmacology, 2021
NP is a heterogeneous condition, in which water diuresis (high free water clearance and low osmolality), solute diuresis (increased sodium clearance) or a combination of both is the underlying cause [26]. Excessive solute production is secondary to many systematic disease states, including congestive heart failure, chronic kidney disease, diabetes insipidus, obstructive sleep apnea and peripheral edema. In the absence of identifiable contributing factors, patients with NP are said to have nocturnal polyuria syndrome (NPS) caused by water diuresis [27]. Water diuresis is thought to result from an abnormality of the circadian rhythm of secretion of the antidiuretic hormone, arginine vasopressin (AVP) [26]. The secretion of vasopressin follows a circadian pattern that traditionally results in reduced urine production at night [26]. Through its action on the AVR-V2 receptor, AVP increases the reabsorption of water in collecting tubules of the kidney, decreasing urine production, and postponing voiding [28]. However, irregularities in vasopressin secretion can result in increased urine production [26].
Development and optimization of osmotically controlled drug delivery system for poorly aqueous soluble diacerein to improve its bioavailability
Published in Drug Development and Industrial Pharmacy, 2020
Magdy I. Mohamed, Abdulaziz M. Al-Mahallawi, Sami M. Awadalla
Osmotic pump Controlled Release Preparation is a novel drug delivery system. It gains a vital interest in oral solid dosage form development chiefly because of their ability to deliver drugs at constant rates (zero-order release) independent of media pH and hydrodynamics of the surrounding media [14,15]. Osmosis can be defined as the spontaneous movement of a solvent from a lower solute solution to a solution of higher solute concentration through an ideal semi-permeable membrane, which is permeable only to the solvent but impermeable to the solute [16,17]. The preparation consists of the core that contained the active material, a semi-permeable membrane that coated the core and an orifice, produced by a micro drill or mechanically to release the active material. When the system is in the gastrointestinal tract, fluid enters into the preparation and dissolves the active material within the core [14,17]. Thus the pressure formed in the preparation induces a release of the solution at a slow but continuous rate [18,19]. Therefore, solubility is considered one of the most vital factors affecting the drug release kinetics from the osmotic pump. As well as Osmotic pressure is another vital factor that imbibes water inside the osmotic pump, and it is proportional to the concentration of the osmotic agent [14].
Sustained release formulation of Ondansetron HCl using osmotic drug delivery approach
Published in Drug Development and Industrial Pharmacy, 2020
Ramakant Gundu, Sanjay Pekamwar, Santosh Shelke, Santosh Shep, Deepak Kulkarni
Osmotic systems utilize the principle of osmotic pressure for the delivery of drugs [10]. Drug release from these systems is independent of pH and other physiological parameter to a large extent and it is possible to modulate the release characteristic by optimizing the properties of drug and system. Osmosis refers to the net movement of solvent molecules across a semipermeable membrane from higher to lower solute concentration [11]. Push–pull osmotic pump tablet characterized by swellable pull layer which pull the drug outside from osmotic pump after pushing by swellable push layer [12]. It is a bilayer tablet coated with a semi permeable membrane. The upper compartment contained the drug; lower compartment contained high viscosity polymers, osmogent and was connected to the outside environment via a small delivery orifice. Polyethylene oxide (around 50–70%) was most commonly used polymer in pull and push layer. The system also had the disadvantage of higher cost compare to other extended release products [13].