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Granulation of Poorly Water-Soluble Drugs
Published in Dilip M. Parikh, Handbook of Pharmaceutical Granulation Technology, 2021
Albert W. Brzeczko, Firas El Saleh, Hibreniguss Terefe
In the 1960s, coprecipitates as a formulation approach for poorly soluble drugs were reported in several publications. These systems primarily contained an intimate mixture of a drug and a water-soluble component by coprecipitation from a common solvent via the solvent evaporation process. The water-soluble component was typically a polymer such as PVP or a low molecular weight compound such as urea [68]. In 1971, Chiou and Riegelmann defined solid dispersions as “a dispersion of one or more active ingredients in an inert carrier at the solid-state, prepared by melting, solvent or melt-solvent method” and introduced a classification system of solid dispersions based on the possible physical states of the active ingredient and the carrier [69]. The concept of “Solid Dispersion” evolved when in 1991 Sekiguchi and Obi reported how to produce dispersions of poorly soluble drugs in a water-soluble carrier by forming eutectic mixtures with the aim to improve oral absorption [70].
Radiation Detection Methods
Published in Michael Pöschl, Leo M. L. Nollet, Radionuclide Concentrations in Food and the Environment, 2006
In general, it is necessary to add isotopic or nonisotopic carriers before any radiochemical analysis is commenced. Isotopic carriers serve two functions: to provide additional mass of the element, which aids in the separation process, and to provide a means of measuring the chemical yield. Nonisotopic carriers serve only to aid in the separation of the desired nuclides. The sample preparation step includes drying, ashing, and scavenging, while the sample solubilization and equilibrium step includes dissolution and leaching. Radiochemical concentration and separation includes coprecipitation, ion exchange, and solvent extraction. After the separation step, the radionuclides of interest exists in a pure portion and are used for counting the source preparation by autoplating (as for polonium isotopes), electroplating, or coprecipitation (as for uranium, plutonium, and thorium isotopes). As an example, radiochemical analysis of uranium and plutonium isotopes are discussed.
Supercritical CO2 versus water as an antisolvent in the crystallization process to enhance dissolution rate of curcumin
Published in Pharmaceutical Development and Technology, 2022
Fatemeh Sadeghi, Hossein Kamali, Sepideh Kouhestanian, Farzin Hadizadeh, Ali Nokhodchi, Hadi Afrasiabi Garekani
Moreover, a reduction in the viscosity with an increase in temperature can promote the polymer matrix’s chain mobility, reduce polymer chain entanglements, and make it easier for dispersion or diffusion of API into the inner region of the polymer during the supercritical procedure. This could lead to increased CO2 mass transfer and significant CO2 adsorption inside polymer chains and consequently prompt the generation of foamy or porous constructions after depressurization (Liu et al. 2020). In addition, the temperature elevation, and its effects on heat transfer were accountable for the rapid diffusion of the solvent into the SCF, and a favourable influence on the nucleation rate. Finally, the influence of temperature on drug and polymer particle size and architecture is mutual. As a result, it is vital to ponder all of the variables that come into play when polymer and drug coprecipitation occurs during the supercritical procedure (Kanaujia et al. 2015).
Magnetoliposomes: recent advances in the field of controlled drug delivery
Published in Expert Opinion on Drug Delivery, 2021
Sérgio R. S. Veloso, Raquel G. D. Andrade, Elisabete M. S. Castanheira
The iron oxide-based nanoparticles are a class of major biomedical interest owing to the good magnetic properties, stability, biocompatibility, and flexibility of chemical modification [5,30]. The synthesis can be carried out through top-down or bottom-up approaches, though the bottom-up methods are preferentially used, which include chemical strategies such as coprecipitation, thermal decomposition, sol-gel, hydrothermal and solvothermal, and microemulsion synthesis [5,30,31]. Particularly, coprecipitation provides an easy and affordable way to produce nanoparticles with different chemical compositions. For instance, different bare ferrite nanoparticles were synthesized through coprecipitation, including ferrites doped with manganese [16], calcium [32], magnesium [17], and nickel [15], and posteriorly formulated into magnetoliposomes. However, considering the inherent toxicity of transition metals and that ferrites are prone to the generation of reactive oxygen species (ROS), calcium and magnesium have been recently proposed as substitutes of the commonly used doping transition metals to improve biocompatibility [31,32].
Development and characterization of novel ambroxol sustained-release oral suspensions based on drug-polymeric complexation and polymeric raft formation
Published in Pharmaceutical Development and Technology, 2020
Ahmad Bani-Jaber, Samaa Abdullah
Binding of ABX to CRG as a function of ABX concentration was reported in Figure 1 showing that binding increased linearly for drug concentrations up to 10 mg/ml, beyond which it tapered off. Statistical analysis for the significance of the increase in binding was performed by t-test for the consecutive pairs of ABX concentration. p Values increased progressively from <0.001 between the lowest concentrations (1 and 2 mg/ml) to reach the highest value of 0.46 between the highest concentrations (10 and 11 mg/ml), implying an insignificant increase of ABX binding as drug concentration was increased beyond 10 mg/ml. At this concentration, maximum binding of almost 1:1 weight ratio was achieved. This maximum binding was obtained by combining equal volumes of CRG and ABX solutions of concentrations 10 and 20 mg/ml, respectively. Thus, these solutions were used to prepare the complex by coprecipitation. Alternatively, the complex was prepared by aqueous kneading of equal amounts of ABX and CRG.