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Thickening Agents
Published in Heather A.E. Benson, Michael S. Roberts, Vânia Rodrigues Leite-Silva, Kenneth A. Walters, Cosmetic Formulation, 2019
Ricardo D’Agostino Garcia, Antony O’Lenick, Vânia Rodrigues Leite-Silva
Hydroxypropyl methylcellulose (HPMC) is a modified natural carbohydrate polymer derived from cellulose. The hydroxypropyl and methyl group substituents impart water solubility and surface activity to the polymer. A variety of HPMC types are commercially available, and their properties determined by the degree of methyl and hydroxypropyl substitution, as well as their molecular weight. HPMC is a multifunctional additive that offers a broad range of impressive properties addressing multiple needs in rinse-off applications even at low use levels. The most important properties include a foam-boosting effect, a significantly improved skin feel, and viscosity control in cleansing and conditioning personal care formulations. The incorporation of HPMC reduces the required amount of certain ingredients, such as surfactants, other thickeners and emollients, without sacrificing performance.
Gastrointestinal Function and Toxicology in Minipigs
Published in Shayne C. Gad, Toxicology of the Gastrointestinal Tract, 2018
Maria R. Jones, Alain Stricker-Krongrad
Vehicles themselves can cause toxic effects, and those should be considered when selecting formulations. One example used in minipigs is Miglyol 812. When dosed with 2 mL/kg/day animals showed gastrointestinal symptoms such as loss of appetite, dry/dark feces, or few feces. Abdominal spasms and vomiting occurred during preliminary studies when dosing minipigs at 10 mL/kg. Histopathological changes to the GI system were considered incidental and not associated with Miglyol 812. However, the primary lesions described were to the lungs, and could be due to regurgitation and subsequent aspiration of the viscous material dosed by oral gavage (Le Bars et al. 2015). Understanding potential adverse reactions of a vehicle is crucial in making toxicology determinations. Short-term oral administration of low levels (0.5% in distilled water) of carboxymethylcellulose or hydroxypropyl methylcellulose did not show any adverse reactions when orally dosed in minipigs (at 8 mL/kg and 5 mL/kg, respectively). However, 90-day daily administration of Transcutol has been shown to be toxic when orally dosed in minipigs, causing liver and kidney damage, with the NOAEL being 167 mg/kg/day. Mixtures of vehicles with low levels of trascutol for short-term oral dosing have shown mild transient diarrhea after initial dose, but a different formulation showed no adverse reactions. A summary of safety assessments of orally dosed vehicles is presented in Table 7.2 (Gad et al. 2016).
Polysaccharide-Based Polymers in Cosmetics
Published in E. Desmond Goddard, James V. Gruber, Principles of Polymer Science and Technology in Cosmetics and Personal Care, 1999
E. Desmond Goddard, James V. Gruber
iv. Hydroxypropylmethylcellulose. Hydroxypropylmethylcellulose (40) shares most of the characteristics of methylcellulose But the presence of the hydroxypropyl groups affords hydrophilic domains lacking in MC. This allows the HPMC to function better in some systems in which MC shows only marginal success. a)
Poloxamer sols endowed with in-situ gelability and mucoadhesion by adding hypromellose and hyaluronan for prolonging corneal retention and drug delivery
Published in Drug Delivery, 2023
Ling-Chun Chen, Shyr-Yi Lin, Wei-Jie Cheng, Ming-Thau Sheu, Chi-Yun Chung, Chen-Hsuan Hsu, Hong-Liang Lin
Hyaluronic acid (HA) can relieve irritation, moisturize the ocular surface, and overcome the sodium hyaluronate deficiency in the tear film, thus alleviating DED symptoms. Hence, HA is the main ingredient in artificial tear formulations currently used for treating DED and Sjögren’s syndrome (Yang et al., 2021). Moreover, the mucoadhesive property and high viscosity of HA (Sudha & Rose, 2014) prevents the rapid washout of the drug by tears, thus prolonging the residence of drug and increasing ocular drug availability (Salwowska et al., 2016). Besides, the high molecular weight (MW) of HA inhibits inflammation by suppressing the production of inflammatory cytokines (Ruppert et al., 2014), which is beneficial for DED (Yamaguchi, 2018). The advantages of the cellulose derivatives of hydroxypropyl methylcellulose (HPMC) include safety, biocompatibility, and mucoadhesive property, which make them suitable for use as ODDS. Moreover, the mucoadhesive property of HPMC enables long contact time, allowing the drug to easily permeate the eye tissue (Tundisi et al., 2021). Therefore, we hypothesize that the addition of HPMC and HA would convert nongellable P407 aqueous solution into an in-situ gellable hydrogel with enhanced mucoadhesive characteristics. Accordingly, we developed P407-based thermosensitive in-situ hydrogels combined with HPMC and HA to reduce the desired concentration of P407 required for maintaining the formation of in-situ hydrogels with an enhanced mucoadhesive property to increase residence time for the continuing ocular delivery of solubilized testosterone in this study.
A novel osmoprotective liposomal formulation from synthetic phospholipids to reduce in vitro hyperosmolar stress in dry eye treatments
Published in Journal of Liposome Research, 2023
Miriam Ana González Cela Casamayor, José Javier López Cano, Vanessa Andrés Guerrero, Rocío Herrero Vanrell, José Manuel Benítez del Castillo, Irene Teresa Molina Martínez
The composition of the aqueous dispersion included H3BO3 8.38%, Na2B4O7 0.755%, ribitol 0.5%, and taurine 0.5%. The final formulations were obtained by 1:1 dilution with the previously mentioned solution with or without hydroxypropylmethylcellulose (HPMC). In the case of formulations F1 and F3, the dilution was performed with the same aqueous phase. For formulations F2 and F4, the dilution was performed with a 0.4% HMPC solution included in the same aqueous buffer, giving a final HPMC concentration of 0.2%. Optimal concentrations of all the substances were selected according to the mechanical characteristics (ability of the liposomes to pass through the extruder filter membranes), desired osmolarity of the aqueous phase (lower than isotonicity), and in vitro tolerability.
Innovations in Corneal Crosslinking
Published in Current Eye Research, 2023
Klara Borgardts, Johannes Menzel-Severing, Isaak Fischinger, Gerd Geerling, Theo G. Seiler
The most promising and currently frequently used agent is HPMC (hydroxypropyl methylcellulose). Ehmke et al. investigated stromal riboflavin gradients after a 10 min application of 0.1% riboflavin/1.1% HPMC and compared it to the conventional 30 min application of 0.1% riboflavin/20% dextran by 2-photon-fluorescence microscopy.32 The results were remarkable: The HPMC-assisted riboflavin solution achieved similar stromal riboflavin gradients compared to the dextran-assisted riboflavin solution within only 10 min of application time instead of 30 min. As a side-effect, HPMC-assisted imbibition resulted in mild corneal swelling of approx. 5%, avoiding the risk of a pre-UV-irradiation pachymetry of less than 400 microns. Fischinger et al. investigated the biomechanical stiffening response ex-vivo with both solutions and favored dextran-assisted CXL.33 It is still under debate which solution has the clinically higher efficacy, however, recent publications support that both solutions may stop disease progression sufficiently.34,35