Concentration Of Glycolic Acid Research Articles

Comparative Effects of Efavirenz and Dolutegravir on Metabolomic and Inflammatory Profiles, and Platelet Activation of People Living with HIV: A Pilot Study.

Antiretroviral therapy (ART) has reduced the mortality and morbidity associated with HIV. However, irrespective of treatment, people living with HIV remain at a higher risk of developing non-AIDS-associated diseases. In 2019, the World Health Organization recommended the transition from efavirenz (EFV)- to dolutegravir (DTG)-based ART. Data on the impact of this transition are still limited. The current study therefore investigated the metabolic profiles, cytokine inflammatory responses, and platelet activation before and after the treatment transition. Plasma samples from nine virally suppressed adults living with HIV and sixteen healthy, HIV-uninfected individuals residing in Gauteng, South Africa were compared. Metabolite and cytokine profiles, and markers associated with platelet activation, were investigated with untargeted proton magnetic resonance metabolomics, multiplex suspension bead array immunoassays, and sandwich enzyme-linked immunosorbent assays, respectively. In those individuals with normal C-reactive protein levels, the transition to a DTG-based ART regimen resulted in decreased concentrations of acetoacetic acid, creatinine, adenosine monophosphate, 1,7-dimethylxanthine, glycolic acid, 3-hydroxybutyric acid, urea, and lysine. Moreover, increased levels of formic acid, glucose, lactic acid, myo-inositol, valine, glycolic acid, and 3-hydroxybutyric acid were observed. Notably, levels of interleukin-6, platelet-derived growth factor-BB, granulocyte-macrophage colony-stimulating factor, tumor necrosis factor-alpha, soluble cluster of differentiation 40 ligand, as well as regulated on activation, normal T-cell expressed and secreted (RANTES) reached levels close to those observed in the healthy control participants. The elevated concentration of macrophage inflammatory protein-1 alpha was the only marker indicative of elevated levels of inflammation associated with DTG-based treatment. The transition from EFV- to DTG-based regimens therefore appears to be of potential benefit with metabolic and inflammatory markers, as well as those associated with cardiovascular disease and other chronic non-AIDS-related diseases, reaching levels similar to those observed in individuals not living with HIV.

Study to compare the efficacy of 50% glycolic acid with 65% trichloroacetic acid in the treatment of atrophic acne scar by CROSS technique.

Acne scars often become challenging to treat with satisfactory results. The chemical reconstruction of skin scars (CROSS) technique has been used with high concentrations of trichloroacetic acid (TCA) which often produces unacceptable side effects. There is a dearth of data, with 50% glycolic acid (GA) for the same indication in the management of acne scars in the Indian population. This study aimed to assess the clinical response of acne scars after the application of 50% GA with that after the use of 65% TCA in a similar manner. An institution-based prospective comparative study was performed with patients aged 16-45 years of either sex with acne scars and not been treated within the past 1 year. Subjects were assigned to receive one of the formulations (50% GA [Group A] and 65% TCA [Group B]). Grading of scars was done on day 1 and day 35 based on patients' assessment on a four-point visual scale and physicians' assessment by the Goodman-Baron qualitative global acne scar grading scale. The procedure was repeated every fortnightly for three such. Data were analyzed by Statistica version 6 (Tulsa, Oklahoma: StatSoft Inc. 2001). The visual improvement scale of patients showed 41.38% (n = 12) fair improvement in group A, whereas 58.06% (n = 18) showed good improvement in group B. Grading by the Goodman-Baron scale showed 9.68% (n = 3) showed four grade changes in group B. Improvement is best observed with 65% TCA. Adverse effects were noted more with 65% TCA, especially acneiform eruption which was lacking in the previous studies. GA can be a safer alternative to TCA with acceptable results. Our study opens the scientific window for future research on different concentrations of GA as a CROSS agent.

Improvement in Ethylene Glycol Bioconversion to Glycolic Acid by Gluconobacter oxydans Using Central Composite Experimental Design and Bioreactor Fed-Batch Strategies

This study focuses on optimizing the medium composition for cellular biomass production and bioconversion of ethylene glycol (EG) to glycolic acid (GA) using Gluconobacter oxydans CCT 0552. The improvement in cellular growth in the presence of yeast extract and peptone led to a 35.7% and 32.7% increase, respectively, compared to the medium with each of these carbon sources separately. Negligible growth was produced when (NH4)2SO4 and urea were used. Optimal bioconversion results were very similar for both the stirred tank and bubble column bioreactors, with GA concentrations reaching 49.4 g/L and 47.7 g/L, volumetric productivities of 0.35 g/L∙h and 0.33 g/L∙h, and product yield factors of 1.08 g/g and 0.94 g/g, respectively. An extended fed-batch strategy using a STR-type bioreactor achieved a concentration of glycolic acid of 94.2 g/L, corresponding to a volumetric productivity of 0.41 g/L∙h and a yield factor of 1.19 g/g. The resulting efficiency of this biological transformation process achieved a remarkable value of 97.3%, simultaneously with a significant decrease in the substrate amount by 90.5%. This study demonstrates the efficiency of G. oxydans in producing GA, offering a cost-effective and environmentally sustainable production method.

Evaluation of eye irritation potential of experimental cosmetic formulations containing glycolic acid, salicylic acid and ethanol using the Bovine Corneal Opacity and Permeability Assay

Objective Prototype cosmetic formulations containing short-chain acids and alcohols intended to be applied in the proximity of the eyes are sometimes evaluated for ocular irritation potential using the validated Bovine Corneal Opacity and Permeability Assay (OECD TG 437). We evaluated the eye irritation potential of nine experimental cosmetic formulations designed and prepared by Avon Global Reserach and Development to differ only in the concentrations of Ethanol, Glycolic Acid and Salicylic Acid. Methods We analysed the data generated using the BCOP assay. The opacity and permeability values obtained following the exposure of bovine corneas to experimental cosmetic formulations were combined into a single In Vitro Irritancy Score used to rank eye irritation potential. Histopathological examination of treated corneas was used to provide additional information about the depth and degree of the injury and to support the prediction of eye irritation potential of each experimental cosmetic formulation. Results The In Vitro Irritancy Scores and histopathological analysis showed that experimental formulations containing only Ethanol, Glycolic Acid, or Salicylic Acid alone had, at most, a mild ocular irritation potential. The experimental formulations containing both Ethanol and Glycolic Acid had a mild ocular irritation potential, while the experimental formulations containing both Ethanol and Salicylic Acid had a moderate ocular irritation potential. Severe ocular irritation potential was induced by an experimental formulation containing a combination of Glycolic Acid and Salicylic Acid and it was further accentuated by the addition of Ethanol to the formulation. Our data indicate a possible synergistic effect on eye irritation potential of Ethanol, Glycolic Acid and Salicylic Acid in at least some experimental cosmetic formulations. Further, our results provide insight on an apparent concentration-dependent ocular irritation potential effect of combinations of Glycolic Acid, Salicylic Acid and Ethanol in at least one experimental cosmetic formulation. Conclusions The results presented herein emphasise the need to consider in vitro testing of prototype cosmetic formulations containing combinations of Ethanol, Glycolic Acid and Salicylic Acid rather than relying on any predicted additive effect on ocular irritation based solely on previously generated results of similar formulations containing Ethanol, Glycolic Acid or Salicylic Acid alone. Further work is required to understand the significance of these observations and to elucidate the mechanisms responsible for the apparent synergistic effects of Glycolic Acid, Salicylic Acid and Ethanol and eye irritation potential suggested by our results.

Glycolic acid-induced disruption of epidermal homeostasis in a skin equivalent model: Insights into temporal dynamics and mechanisms

Glycolic acid (GA) is extensively used in cosmetic formulations and skin peeling treatments but its adverse effects, notably severe disruption of epidermal structure, limit its clinical utility. However, the detailed impact of GA on epidermal homeostasis, including changes in structure and protein expression over time, is not fully understood. This study employed a reconstructed human epidermis (RHE) model to assess the effects of varying GA concentrations on epidermal proliferation, differentiation, and desquamation at different time points. Through histology, immunofluorescence, and immunohistochemistry, we observed that 35% GA concentration adversely caused abnormal epidermal homeostasis by affecting epidermal proliferation, differentiation and desquamation. Our findings reveal time-specific responses of key proteins to GA: Filaggrin, Involucrin, Loricrin, and Ki67 showed very early responses; KLK10 an early response; and AQP3 and K10 late responses. This research provides a detailed characterization of GA's effects in an RHE model, mimicking clinical superficial peeling and identifying optimal times for detecting GA-induced changes. Our results offer insights for designing interventions to mitigate GA's adverse effects on skin, enhancing the safety and efficacy of GA peeling treatments.

Systematic Optimization of Automated Phosphopeptide Enrichment for High-Sensitivity Phosphoproteomics

Improving coverage, robustness, and sensitivity is crucial for routine phosphoproteomics analysis by single-shot liquid chromatography-tandem mass spectrometry (LC-MS/MS) from minimal peptide inputs. Here, we systematically optimized key experimental parameters for automated on-bead phosphoproteomics sample preparation with a focus on low-input samples. Assessing the number of identified phosphopeptides, enrichment efficiency, site localization scores, and relative enrichment of multiply-phosphorylated peptides pinpointed critical variables influencing the resulting phosphoproteome. Optimizing glycolic acid concentration in the loading buffer, percentage of ammonium hydroxide in the elution buffer, peptide-to-beads ratio, binding time, sample, and loading buffer volumes allowed us to confidently identify >16,000 phosphopeptides in half-an-hour LC-MS/MS on an Orbitrap Exploris 480 using 30 μg of peptides as starting material. Furthermore, we evaluated how sequential enrichment can boost phosphoproteome coverage and showed that pooling fractions into a single LC-MS/MS analysis increased the depth. We also present an alternative phosphopeptide enrichment strategy based on stepwise addition of beads thereby boosting phosphoproteome coverage by 20%. Finally, we applied our optimized strategy to evaluate phosphoproteome depth with the Orbitrap Astral MS using a cell dilution series and were able to identify >32,000 phosphopeptides from 0.5 million HeLa cells in half-an-hour LC-MS/MS using narrow-window data-independent acquisition (nDIA).

Delayed Graft Function After Kidney Transplantation: The Role of Residual Diuresis and Waste Products, as Oxalic Acid and Its Precursors.

Delayed graft function (DGF) after kidney transplantation heralds a worse prognosis. In patients with hyperoxaluria, the incidence of DGF is high. Oxalic acid is a waste product that accumulates when kidney function decreases. We hypothesize that residual diuresis and accumulated waste products influence the DGF incidence. Patients transplanted between 2018-2022 participated in the prospective cohort study. Pre-transplant concentrations of oxalic acid and its precursors were determined. Data on residual diuresis and other recipient, donor or transplant related variables were collected. 496 patients were included, 154 were not on dialysis. Oxalic acid, and glyoxylic acid, were above upper normal concentrations in 98.8%, and 100% of patients. Residual diuresis was ≤150mL/min in 24% of patients. DGF occurred in 157 patients. Multivariable binary logistic regression analysis demonstrated a significant influence of dialysis type, recipient BMI, donor type, age, and serum creatinine on the DGF risk. Residual diuresis and glycolic acid concentration were inversely proportionally related to this risk, glyoxylic acid directly proportionally. Results in the dialysis population showed the same results, but glyoxylic acid lacked significance. In conclusion, low residual diuresis is associated with increased DGF incidence. Possibly accumulated waste products also play a role. Pre-emptive transplantation may decrease the incidence of DGF.

Photoautotrophic organic acid production: Glycolic acid production by microalgal cultivation

• The C. reinhardtii GYD1 mutant secretes glycolic acid using CO 2 . • Two-stage continuous culture enhanced glycolic acid production of the GYD1 mutant. • The productivity of glycolic acid was increased by 122.6 mg L -1 d -1 . • The glycolic acid production rate of the culture was 69% of the simulated value. • The minimum glycolic acid production cost was estimated to be $31 kg −1 by TEA. Although microalgae produce value-added products, such as lipids, pigments, and polysaccharides using light and carbon dioxide, these intracellular products require costly downstream processes such as extraction and purification. Thus, extracellular products are desirable for economic production. While reported before, the secretion of glycolic acid by microalgal photorespiration has not received attention for industrial applications. We developed a two-stage continuous cultivation system to increase glycolic acid production using a glycolate dehydrogenase ( GYD1 ) deficient mutant of Chlamydomonas reinhardtii which produces high concentrations of glycolic acid. Specifically, 3% CO 2 was supplied in the first-stage culture for the production of biomass and ambient air (0.03% CO 2 ) was supplied to the second stage for the production of glycolic acid. As a result, overall glycolic acid productivity reached 82.0 mg L -1 d -1 at a dilution rate of 0.34 d -1 . However, as the pH of the second stage decreased to 4.7 due to the increased glycolic acid production, we controlled the pH of the second stage at pH 6.0, resulting in 122.6 mg L -1 d -1 of glycolic acid productivity. Flux balance analysis revealed that the experimental glycolic acid production rate was 69% of the theoretical glycolic acid production rate. The deviation might be due to the toxicity of glycolic acid. When a techno-economic analysis was conducted based on the experimental results, the minimum glycolic acid production cost was estimated to be $31 kg −1 , indicating a potential for industrial production. These findings suggest that microalgae can be utilized for the cost-effective industrial production of glycolic acid.

Efficacy of 70% Glycolic Acid Peel versus 30% Salicylic Acid Peel in the Treatment of Mild to Moderate Acne Vulgaris: A Retrospective Study

Introduction: Chemical peels have become a useful modality in the management of acne in addition to topical and systemic medications. Studies done to evaluate the effectiveness of peels have compared only lower concentration of Glycolic Acid (GA) (35%) and Salicylic Acid (SA) peels. Higher concentrations of glycolic acid i.e., (70%) are reported to be safe and more effective than lower concentrations. Despite reported advantages of higher concentration of glycolic acid peel, no published data is available regarding its efficacy, safety and tolerability in comparison with other peels. Aim: To compare the effectiveness of 70% GA peel with 30% SA peel in the management of mild to moderate acne. Materials and Methods: The present study was a cross-sectional retrospective study conducted from December 2021 to April 2022 in which, 60 participants were enrolled. They were diagnosed with mild to moderate acne, based on the Indian Acne Alliance (IAA) grading system and all of them underwent chemical peel treatment. Among them 30 had received 70% GA peel (group 1) and 30 had received 30% SA peel (group 2). The number of sittings and the individual lesional count at baseline and at each sitting were recorded. Acne lesional count (sum of comedones, papules, pustules, and nodules) was recorded at baseline, 2, 4, 6 and 8 weeks. Categorical variables were presented as frequency and percentages. Continuous variables were presented as Mean±Standard deviation. Results: There was a significantly greater decrease in mean acne lesional count in group 2 from the baseline of 25.73 to 13.83 at the end of 2nd weekin comparison to group 1 wherein the values reduced from 26.30 to 17.73 (p-value of 0.003). At the end of eight weeks, the mean acne lesional count of both groups (group 1- 2.17 and group 2-1.50, p-value of 0.097) were comparable. Conclusion: Higher concentration of GA (70%) has comparable effectiveness to 30% SA peel in management of mild to moderate acne. SA peel has an advantage of earlier decrease in lesional count.

High efficiency and clean separation of eucalyptus components by glycolic acid pretreatment

Glycolic acid has chemical properties similar to those of formic acid. Therefore, similar to formic acid pretreatment, glycolic acid pretreatment has the separation effect of hemicellulose. In this study, eucalyptus hemicellulose was effectively separated by glycolic acid pretreatment. The effects of glycolic acid concentration, temperature and time on the separation of cellulose, hemicellulose and lignin were investigated. The optimum conditions were acid concentration 5.40%, temperature 140 °C, time 3.0 h. The highest yield of xylose was 56.72%. The recovery rate of glycolic acid was 91%. Compared to formic acid, the yield of xylose increased to 10.33% while that of lignin decreased to 11.08%. It showed high selectivity for hemicellulose separation, yielding 65.48% hemicellulose with 72.08% purity. The depolymerization and repolymerization of lignin were inhibited. The integrity of the cellulose structure was preserved. It provides theoretical support for the fractional separation and high-value transformation of lignocellulosic biomass.

Clinical outcomes and 5-year follow-up results of keratosis pilaris treated by a high concentration of glycolic acid.

BACKGROUNDKeratosis pilaris is a hereditary abnormal keratosis of the hair follicle orifice. Gray-brown keratotic plugs in the pores and dark red keratotic papules at the openings of hair follicles can be seen, which contain coiled hair and are often accompanied by perifollicular erythema and pigmentation. Glycolic acid can correct the abnormalities of hair follicular duct keratosis and eliminate excessive accumulation of keratinocytes. It also promotes skin metabolism and accelerates the melanin metabolism. The therapeutic effect is related to the glycolic acid concentration.AIMTo evaluate the efficacy and safety of a high concentration of glycolic acid in the treatment of keratosis pilaris, and to observe the outcomes at 5-year of follow-up.METHODSTwenty-five participants were recruited and areas with typical keratosis pilaris were selected as testing sites. High concentrations of glycolic acid (50% or 70%) were applied to a circular area (d = 8 cm, S = 50 cm2) and repeated four times, on days 0, 20, 40 and 60. Before each treatment and 20 d after the last treatment, on days 0, 20, 40, 60, and 80 and at a 5-year follow-up, The number of follicular keratotic papules were counted and the extent of perifollicular erythema and pigmentation was determined. At the same time, the participants provided subjective evaluations of treatment efficacy and safety.RESULTSTreatment effectiveness was indicated by the percentage of keratotic papules in the test site, on days 20, 40, 60 and 80, which were 8%, 12%, 36%, and 60%, respectively. Compared with day 0, each difference was significant (P < 0.05). Compared with day 0, differences in melanin content (M) in the skin and skin lightness (L) on days 40, 60 and 80, the were statistically significant (P < 0.05); skin hemoglobin content (E) on days 60 and 80 was statistically different as compared with before treatment (P < 0.05). There were no significant differences in the number of keratotic papules, M, L, and E in 9 participants at the 5-year follow-up compared with before treatment (P > 0.05%).CONCLUSIONA high concentration of glycolic acid significantly improved skin roughness as well as follicular hyperpigmentation of patients with keratosis pilaris. The treatment was relatively safe, but there was no significant difference at the 5-year follow-up compared to before treatment.

Formulation of topical acidic products and acidification of the skin - Contribution of glycolic acid.

The acidic skin pH is one of the regulating factors of skin barrier homeostasis. Topical products as extrinsic factors which influence skin pH could be used for acidification of the skin and consequent beneficial effect. To formulate stabile and safe topical emulsion product with low pH is on-going challenge and areas interesting to explore are related to the effect of acidic products on the skin pH together with development of protocols for these studies. Aim of our work was to investigate formulations of acidic topical products with glycolic acid (GA) stabilized with long chain alkyl polyglucoside emulsifier, in regard to the specific colloidal structure of the vehicle, together with effect of products with different concentration of acidic active on skin pH. Investigated formulations were basic vehicle and two creams with glycolic acid (concentration 2 and 10 wt%). Microstructure was investigated by polarization microscopy, Raman spectral imaging, thermal analysis and rheological measurements. Effects on the skin were assessed by measurement of biophysical skin parameters in vivo studies (5-hour, 24-hour and 7-days). In vitro screening of antimicrobial activity was performed against bacteria Staphylococcus epidermidis. Polarization micrographs and Raman images have shown that GA does not disturb the specific colloidal structure. Together with rheological and thermal analysis obtained results have shown that GA in higher concentrations contributes to vehicles' lamellar structure. In 5-hour study the mean values of skin pH ranged from 3.98-4.25 and 3.89-4.10 after application of products with smaller and higher GA concentration. GA samples lowered skin surface pH to 5 and less in 24-hour and 7-day study, with stronger effect of sample with more GA. Sample with 10% of GA had significant inhibitory effect on growth of S. epidermidis in 1:1 concentration. Investigated APG emulsifier could be used as a stabilizer for acidic topical products with GA which are characterized by satisfactory safety profile. Topical products induce acidification of the skin after short- and long-term application without barrier impairment or sign of irritation. Acidification of the skin depends on presence of ingredients which are proton donors and their concentrations.

Cytotoxicity of different concentrations of glycolic acid and its effects on root dentin microhardness - An invitro study.

The aim of the study was to evaluate the cytotoxicity of different glycolic acid concentrations (GA) and its effects on dentinal microhardness. Cytotoxicity was evaluated after inoculation of test irrigants in the lymphocyte primary culture for 3 min. The tested substances were distilled water(DW); 17% EDTA; QMix; 10% GA; 17% GA; and 25% GA. Counting of total, live and dead cells was performed, obtaining the average percentage of dead cells of each group. For microhardness evaluation, 60 root dentin samples were divided into the same tested groups (n = 10) and immersed in test irrigants for 3 min. Dentin microhardness was evaluated by Vicker test. Specific statistical analysis was made in both tests. Results showed significant lower cytotoxicity for QMix and 10% GA (P < 0.05). Moreover, all test irrigants presented similar values of microhardness than the control group (P > 0.05). In conclusion, lower GA concentration can be an alternative for final irrigation on endodontics.

Catalytic Production of Glycolic Acid from Glycerol Oxidation: An Optimization Using Response Surface Methodology

This study aimed at optimizing the production of glycolic acid from glycerol catalytic oxidation over a silver catalyst supported on a mixed cerium-zirconium oxide, to progress towards the industrialization of a derived process. Optimization of the operating conditions was performed using the response surface methodology. We concluded that the production of glycolic acid depends mainly of glycerol concentration, NaOH/glycerol ratio, catalyst/glycerol ratio, and O2/glycerol ratio. The optimal conditions we found were a temperature of 60 °C, a NaOH/glycerol molar ratio of 2, an O2/glycerol molar ratio of 0.23, and a catalyst/glycerol mass ratio of 0.07. With these optimal conditions, it was possible to increase the glycerol concentration from 0.3 M to 2 M, obtaining an increase in the concentration of glycolic acid in the liquid fraction, from 0.27 mol/L of glycolic acid (with initial glycerol solution 0.3 M) to 0.88 mol/L (with initial solution 2 M), while keeping a 100% glycerol conversion.

Efficacy of Glycolic Acid on Debris and Smear Removal as a Final Rinse Solution in Curved Canals: A Scanning Electron Microscope Study.

Aim:This study aims to compare intraradicular smear layer removal efficacy of different concentrations of glycolic acid (GA), 17% ethylenediaminetetraacetic acid (EDTA), and 10% citric acid (CA) as final rinses in the canals of curved mesial root of mandibular first molars using the specific irrigant protocols.Materials and Methods:Fifty-eight mandibular first permanent molars with 15°–30° of curvature of the mesial roots were selected, standardized, mesiobuccal canal prepared using the rotary instrumentation. Sodium hypochlorite was used as initial rinse solution (8 ml). The samples were divided into control (n = 5) (I – Normal saline and II – 17% EDTA) and experimental groups (n = 8) (Groups III, IV, V, VI, VII, and VIII) based on the type of final rinse solution (5 ml) used, i.e. 2.5% GA, 5% GA, 10% GA, 17% GA, 37% GA, and 10% CA. Samples were split buccolingually, dehydrated, splutter coated, and examined under a scanning electron microscope.Results:Group IV presented the least amounts of smear among the GA experimental groups at the apical, middle, and coronal one-thirds of the root canal with a mean value of 2.6 ± 1.012, and on comparison with Group II, the results were comparable, and no significant difference found statistically (P > 0.05).Conclusion:The use of GA as final rinse solution for biomechanical preparation during endodontic therapy seems promising. Further evaluation in a clinical setting is recommended.

Glycolic acid adjusted to pH 4 stimulates collagen production and epidermal renewal without affecting levels of proinflammatory TNF-alpha in human skin explants.

BackgroundGlycolic acid (GA) is an effective way of reversing the signs of age and photodamage. GA enhances desquamation of the stratum corneum and induces biological responses that can help restore skin's integrity. GA can, however, cause irritation, especially when its concentration is high, and its pH is low. Thus, most commercially available products for home use contain relatively low GA concentrations and are partially neutralized to a pH around 4.AimsThe aim of this study was to determine the biological effects and relative efficacy of cosmetic formulations containing GA at concentrations ranging from 8% to 25% at pH 4 in human ex vivo skin explants.MethodsHuman skin explants were topically treated with gel formulations and oil‐in‐water creams containing 8%, 10%, 15%, or 25% GA, adjusted to pH 4, daily for 5 days. The degree of desquamation, their effect on cell proliferation, and their impact upon total collagen levels were determined 24 hours later. Levels of tumor necrosis factor‐alpha (TNF‐α) were measured after days 3 and 6.ResultsAll formulations effectively induced desquamation in a concentration‐dependent manner. Total collagen levels were increased at all concentrations, with greatest effects at higher GA concentrations. No effect on TNF‐α expression was observed.ConclusionsThese data suggest that partially neutralized GA formulations retain skin rejuvenating properties without causing irritation and inflammation and that their use can be tailored to individual needs based on the concentration of GA in the formulation.

PH-Dependent Antibacterial Activity of Glycolic Acid: Implications for Anti-Acne Formulations

Glycolic acid is the smallest alpha hydroxy acid and widely used for skincare applications, including to treat acne vulgaris. Oftentimes, high concentrations of glycolic acid (~20–50 vol%) are incorporated into chemical peels to reduce acne-related inflammation while there is an outstanding need to determine to what extent glycolic acid can potently inhibit Cutibacterium acnes (formerly known as Propionibacterium acnes), which is a Gram-positive bacterium implicated in acne pathogenesis. Herein, we report that glycolic acid exhibits pH-dependent antibacterial activity against C. acnes and mechanistic studies identified that the nonionic form of glycolic acid is more active than the anionic form. The degree of antibacterial activity, including minimum bactericidal concentration (MBC), of glycolic acid was evaluated in the pH range of 3 to 4.5, and the greatest potency was observed at pH 3. In light of skincare formulation needs, we selected the pH 3.5 condition for further testing and determined that glycolic acid kills C. acnes cells by disrupting bacterial cell membranes. While most conventional treatments involve high concentrations of glycolic acid (>20%), our findings support the potential of developing anti-acne formulations with glycolic acid concentrations as low as 0.2% and with pH conditions that are suitable for over-the-counter applications.

Glycolic acid: Characterization of a new final irrigant and effects on flexural strength and structural integrity of dentin

The aim of this study was to characterize glycolic acid (GA) and examine its effects on powder and flexural strength of dentin. Particle size and energy-dispersive EDS in GA powder was performed for chemical analysis. Surface tension and pH levels of ethylenediaminetetraacetic acid (EDTA), citric acid (CA), and GA solutions were evaluated at different times and temperatures. Dentin powder and mineralized dentin beams were immersed for 1 min in EDTA, CA, or GA solutions and subjected to Fourier transform infrared spectroscopy for apatite/collagen ratio analysis and 3-point flexure test, respectively. GA showed the largest particle size (μm), and its surface tension was similar to that of EDTA and CA. Surface tension decreased in solutions of higher concentrations. GA showed pH stability at all times and temperatures evaluated. The apatite/collagen ratio reduced with increased GA concentrations, while flexural strength was not significantly affected by GA concentration. GA seems a good choice as a final irrigation solution after root canal preparation.

Theoretical and laboratory investigations of the effects of hydroxyproline ingestion on the metabolic and physicochemical risk factors for calcium oxalate kidney stone formation in a small group of healthy subjects.

Dietary hydroxyproline may be involved in the endogenous synthesis of oxalate. Glycolate, produced during the metabolism of hydroxyproline, may exert physicochemical effects on urinary calcium by virtue of its dihydroxycarboxylic acid structure. The aim of this study was to investigate these possible stone-risk scenarios. We modelled the effect of different glycolic acid concentrations on ionized calcium (iCa2+) and relative supersaturation (RSS) of calcium oxalate (CaOx) using the program JESS. Thereafter, three healthy white males and two healthy black males ingested 30g gelatin for 3days. 24-h urines were collected at baseline and after completion of the protocol. Urines were analysed for physicochemical risk factors and for iCa2+ and glycolic acid. Speciation concentrations and RSS values were calculated. Theoretical modelling showed that binding between calcium and glycolate does not occur and that iCa2+ and RSS CaOx are unaffected. However, after ingestion of hydroxyproline, iCa2+ decreased significantly. Urinary pH and glycolate increased significantly. Oxalate excretion and RSS CaOx did not change CONCLUSIONS: We attribute the decrease in iCa2+ to increases in the concentrations of several Ca-phosphate species, the formation of which is due to the increase in pH. We speculate that the absence of an increase in oxalate excretion despite an increase in glycolate excretion may be due to the mixed racial composition of our test group in which some pathways may be preferred to others. Our findings alert stone researchers to the importance of measuring urinary pH in their workup of subjects and to select racially homogenous groups for investigation.

Ionic Conductivity and Structural Analysis of 2-hyroxyethyl Cellulose Doped with Glycolic Acid Solid Biopolymer Electrolytes for Solid Proton Battery

Cellulose derivatives have high potential for use as solid biopolymer electrolytes in proton batteries because they are biodegradable, affordable, have good mechanical properties and their ionic conductivity can be enhanced with addition of ionic dopant. In this work, we developed a new type of solid biopolymer electrolytes (SBEs) based on 2-hydroxyethyl cellulose (2HEC) doped with glycolic acid (GA) as an ionic dopant. A solution casting technique was used to prepare the SBEs. The ionic conductivity and structural properties of the SBEs were analysed using Electrical Impedance Spectroscopy (EIS), Fourier Transform Infrared spectroscopy (FTIR) and an X-ray Diffractometer (XRD). The highest ionic conductivity achieved was 3.80 x10−4 S cm−1 for the sample with 40 wt.% GA concentration at room temperature. FT-IR analysis showed that complexation occurred in the polymer system from the shifting of υC-O and υsCOO- band of 2HEC and GA. FTIR deconvolution revealed the increasing pattern of percentage free mobile ions with the addition of GA concentration until 40 wt.% GA, which can be related to the high ionic conductivity of the sample. In XRD analysis, all SBEs shows amorphous nature. Based on the results obtained, GA is a good ionic dopant because it succeed in improve the ionic conductivity of the 2HEC film.