Nanosuspensions as Nanomedicine: Current Status and Future Prospects
Debarshi Kar Mahapatra, Sanjay Kumar Bharti in Medicinal Chemistry with Pharmaceutical Product Development, 2019
Considering the poor water solubility of most of the chemical moieties, organic solvents are required in the formulation in most of the cases, especially when emulsion and microemulsion as a template is used. The acceptability of the organic solvents in the production of pharmaceuticals, their toxicity potential and the ease of their removal from the formulation needs to be considered when formulating nanosuspensions. The pharmaceutically acceptable and less hazardous water-miscible solvents, such as isopropanol and ethanol, and partially water-miscible solvents, such as ethyl formate, ethyl acetate, butyl lactate, triacetin, propylene carbonate and benzyl alcohol, are preferred over the conventional hazardous solvents, like dichloromethane.
Nail Product Rheology
Laba Dennis in Rheological Proper ties of Cosmetics and Toiletries, 2017
In order to achieve a more rapid and complete viscosity buildup, polar additives are often incorporated as a part of the suspension system. Alpha-hydroxy acids are particularly useful, with malic, tartaric, and citric acids having been used in polishes. Phosphoric acid has also been incorporated as a polar additive. Propylene carbonate has also been employed. The choice, level, and method of incorporation of the polar additive will affect not only the viscosity level, but the rate and manner in which the viscosity builds.
Process parameters of microsphere preparation based on propylene carbonate emulsion-precursors
Published in Journal of Microencapsulation, 2021
Various solvents have been extensively described for such systems, but the use of non-toxic solvents is often suggested in order to avoid issues connected with a complete solvent removal from the microparticulate matrix due to the low toxicity potential of these solvents (Allhenn and Lamprecht 2011; Elkharraz et al.2011, Ali and Lamprecht 2013). However, despite being non-toxic, these solvents also involve technical limitations. The main limitation is a high intrinsic viscosity, which makes e.g. the control of droplet sizes during emulsification troublesome and slows down the diffusion of the solvent from the droplets, subsequently risking a failure in microsphere obtainment. In this context, propylene carbonate (PC) exhibits beneficial properties such as a low toxicity (Beyer et al.1987, Sommer et al.1990, Quintanar-Guerrero et al.1996, Das et al.2017) as well as low viscosity, but also partial water miscibility (Shaikh and Sivaram 1996). This gap in water miscibility enables the formation of emulsion droplets which act as precursor templates for microspheres.
Design and Optimization of PLGA Particles to Deliver Immunomodulatory Drugs for the Prevention of Skin Allograft Rejection
Published in Immunological Investigations, 2020
Khawar Ali Shahzad, Muhammad Naeem, Lei Zhang, Xin Wan, Shilong Song, Weiya Pei, Chen Zhao, Xiaoxiao Jin, Chuanlai Shen
Emulsification-diffusion method is an adsorption or co-coupling technique in which drug is loaded on the surface of PLGA particles. In this technique, the drug can be incorporated after fabrication of particles. The water-soluble solvents such as propylene carbonate or acetone are used in this method. The protein or peptide drugs and polymer are dissolved in the solvent and emulsified at aqueous phase in the presence of a stabilizer. Later on, water is added to the emulsion that allows the diffusion of solvent into water. The solution is homogenized by stirring which lead to precipitation of particles. The particles are then collected by centrifugation (Kwon et al. 2001; Takeuchi et al. 2001). Leakage of water soluble drugs out of polymer during solvent diffusion step is one of the drawbacks of this technique. Therefore, variation in batch to batch production is a major issue in controlled drug delivery system.
The clinical toxicity of imidacloprid self-poisoning following the introduction of newer formulations
Published in Clinical Toxicology, 2021
Varan Perananthan, Fahim Mohamed, Seyed Shahmy, Indika Gawarammana, Andrew Dawson, Nicholas Buckley
Worse clinical outcomes in imidacloprid toxicity could be due to the higher dose seen in the latter cohort but also could be due to solvents, stabilisers and surfactants present in newer formulations of imidacloprid [22,23]. Stabilisers and surfactants in imidacloprid products vary between brands but are not generally disclosed. Common solvents in pesticide formulations vary from low toxicity substances (water, glycerol, propylene glycol, propylene carbonate) to more toxic hydrocarbons. Some formulations of imidacloprid contain N-methyl-2-pyrrolidone (NMP) and dimethylsulfoxide. NMP causes developmental toxicity in rat studies including decreased foetal body weight, incomplete ossification of skulls and malformations [24]. NMP may also cause central nervous depression, gastrointestinal irritation and hyperglycemia [15]. Features of gastrointestinal toxicity were common prior to 2007 and post 2010. Non-specific gastrointestinal symptoms can occur in large volumes of glycerol intake. Furthermore, NMP present in most formulations is corrosive and in large volumes can induce a reactive gastropathy causing abdominal pain [15].
Related Knowledge Centers
- Carbonation
- Chirality
- Epoxide
- Organic Compound
- Propylene Oxide
- Racemic Mixture
- Urea
- Carbonate Ester
- Propylene Glycol
- Chemical Polarity