Impurities in Hyaluronic Acid Dermal Fillers? A Narrative Review on Nonanimal Cross-Linked Fillers.

Importance: Nonanimal cross-linked hyaluronic acid (HA) dermal fillers are among the most versatile tools in minimal invasive esthetic medicine. Filler injections aim to volumize, provide contour, and reduce wrinkles and skinfolds. In the hand of the experienced user, HA fillers have an excellent safety profile. Nevertheless, adverse events have been reported related to poor injection techniques, infection, and immune reactions. Observations: In this review, the focus is on filler impurities. Impurities can originate from the fermentation process, crosslinking, packaging, and contamination. Impurities consist of particular and nonparticular matter. We discuss possible risks for the patient to be treated with HA fillers. Conclusions and Relevance: Impurities of dermal fillers bear a potential risk for patients, such as delayed autoimmune and inflammatory reactions, biofilm formation, and exposure to leachable Endocrine Disrupting Chemicals. Amount and quality of impurities can be considered as one of the quality parameters of commercially fillers. Considering patient safety, filler impurities should be further reduced.

Phthalates leaching from plastic food and pharmaceutical contact materials by FTIR and GC-MS.

Phthalates are often used as plasticizers in the production of plastic food contact materials (FCMs) and pharmaceutical contact materials (PCMs), and having in mind that they are not bound to plastics, phthalates may easily leach from plastics under certain conditions. The aim of this research is determination of phthalates leaching potential from different plastic materials and quantitative determination of 5 phthalates (dimethyl phthalate (DMP), di-n-butyl phthalate (DnBP), benzyl butyl phthalate (BBP), diethyl hexyl phthalate (DEHP), and di-n-octyl phthalate (DOP)) in 44 different plastic articles of 7 different plastic polymers used as FCMs and PCMs by FTIR, GC-MS, and gravimetric methods. The FTIR technique is shown to be rapid method for determination of phthalate content in PVC articles. Comparing of FTIR method with GC-MS and gravimetric showed that separation and quantitative determination of each phthalate separately favor the GC-MS method, because FTIR method determines the total amount of phthalate content. However, the FTIR method is less expensive and demanding in terms of sample preparation, which is suited for use in pre-screening analysis. The results of GC-MS phthalates determination showed that PVC articles used as PCMs contain DEHP in significant amount, from 5.19 to 28.76% by weight and could be a potential risk to human health.

Removal of Cu2+ and Zn2+ from model wastewaters by spontaneous reduction-coagulation process in flow conditions.

The treatment of model wastewaters containing heavy metals by spontaneous reduction-coagulation process using micro-alloyed aluminium composite (MAlC) in a laboratory semi-flow system (SFS) has been investigated. Several working parameters, such as treatment time, pH, initial metal concentration and flow rate were studied in an attempt to achieve a higher removal capacity. The residual concentrations of metals were at admissible levels after only 20 min of treatment. Removal rate of Zn(2+) was greater at neutral pH than at acid or basic, while Cu(2+) removal was less affected by pH. Removal constants of both metals decreased as initial metal concentration increased from 20 to 200 mg L(-1). In mixed wastewaters the presence of copper caused increase of Zn(2+) removal efficacy, however, the copper removal was not affected by zinc. The removal mechanisms depend on metals nature and pH: copper was mainly removed by reduction, while zinc by precipitation as hydroxide. The kinetic of process was mass-transport limited, thus increasing of flow rate accelerated removal of metals. The method was found to be highly efficient and faster compared to conventional treatments.

Spectroscopic and potentiometric studies on derivatized natural humic acid.

Isolated soil humic acid (HA) and commercial Aldrich HA were derivatized by esterification with methanol-thionyl and acetylation with acetic anhidride, in order to obtain derivatives with selectively blocked carboxyl and phenol groups, respectively. Results obtained by FT-IR spectroscopy and potentiometry show that the methanol-thionyl procedure is a selective, specific and efficient route for blocking carboxyl groups. The good correlation between results obtained by direct potentiometry after HA esterification and by classical calcium-acetate and baryta exchange methods suggests that esterification followed by direct acid-base potentiometric titration can be used as a method for the estimation of carboxyl and phenol group contents. Phenol groups can not be specifically identified by the acetylation method, due to the low selectivity of the acetylation method. The average values of apparent and intrinsic pK of underivatized and derivatized HAs confirm decrease in ionizable groups content due to derivatization and their values are related to the different chemical structures of the acids.