HCl pH Research Articles

Statherin-Derived Peptide Protects against Intrinsic Erosive Enamel Wear in situ

Introduction: This in situ study investigated the protective effect of a solution containing statherin-derived peptide (StatpSpS) against enamel intrinsic erosion (ERO). Methods: Fifteen volunteers wore appliances containing 2 bovine specimens. The samples were subjected to ERO with HCl, mimicking dental ERO by intrinsic acid. The volunteers participated in 3 phases (double-blind and crossover): (1) deionized water (negative control); (2) commercial solution containing SnCl2/NaF/AmF (800 ppm Sn+2, 500 ppm F−, pH 4.5) (positive control); (3) solution containing 1.88 × 10−5m StatpSpS. Four times a day, the volunteers administered one drop of the solutions (50 μL, 1 min) on each specimen. After the treatment, erosive challenges were performed extraorally with 0.01 m HCl (pH 2.0, 4 times/day, 1 min, 150 mL). Enamel wear was assessed by profilometry. Data were analyzed by one-way RM-ANOVA/Bonferroni’s tests (p < 0.05). Results: In terms of the treatments, both the commercial solution (SnCl2/NaF/AmF) and StatpSpS significantly reduced the wear when compared to the negative control (p < 0.01), without significant differences between them (p > 0.05). Conclusion: The solution containing StatpSpS demonstrated protection against enamel intrinsic erosive wear. This study marks a significant advancement in the prevention of intrinsic erosive wear, utilizing StatpSpS in acquired pellicle engineering procedures.

Hydrothermal synthesized kaolin group lamellar/spongy aluminosilicates for enhanced lead vapor capture

Developing high-temperature-resistant adsorbents with superior porous properties is crucial for safely disposing of heavy metal-containing solid waste via pyrolysis. We synthesized aluminosilicates hydrothermally and observed that acidic conditions, especially HCl (pH=2.6), favored sponge-like mineral (NC2.6) formation with a specific surface area of 500.31 m²/g and pore volume of 0.986 cm³ /g, while alkaline conditions (pH=12.0) promoted spherical particle growth. NC2.6 exhibited higher adsorption capacity compared to kaolinite and halloysite in the PbCl2 vapor adsorption, reaching a maximum of 137.68 mg/g at 700 ℃ (75.91 % stable). We examined the effect of CO2 and H2O on adsorption efficiency and explored the mechanisms using DFT and GCMC simulations. From GCMC results, CO2 negatively impacted PbCl2 adsorption due to competitive adsorption, while H2O increased adsorption content (144.24 mg/g at 700 ℃) by converting PbCl2 into oxides. DFT revealed the presence of CO2 enhanced the adsorption stability of PbCl2 via the formation of covalent bonds between O in CO2 and Pb, and active O on the aluminosilicate surface. H2O increased PbCl2 adsorption energy, as O in H2O occupied an active Al that originally formed a covalent bond with Cl, while the H formed a weak hydrogen bond with this Cl.

An approach for pH-independent release of poorly soluble ionizable drugs using hot-melt extrusion

Hot melt extrudates with combinations of Soluplus® and Aqoat® AS-LF or Eudragit® E PO were investigated to improve drug release and to overcome the pH-dependent release of poorly water-soluble basic (itraconazole, ITZ) and acidic (mefenamic acid, MFA) drugs. The release of ITZ was improved in both 0.1 N HCl and PBS pH 6.8 by hot-melt extrusion with combinations of Soluplus®:Aqoat® AS-LF and can be adjusted by varying the ratio of the polymers. At the ratio Soluplus®:Aqoat® AS®LF 75:25, an almost pH-independent release was achieved without any drop in the drug concentration within 24 h. A pH-independent and extended release (over 24 h) was obtained from milled extrudates when formulated in erodible matrix tablets using 15 % Methocel® K15M as the carrier. The release of MFA from extrudates with Soluplus® was immediate only in PBS pH 6.8. From extrudates with cationic Eudragit® E PO the release of MFA was slow in 0.1 N HCl and PBS pH 6.8, due to poor drug solubility and insoluble Eudragit® EPO, respectively. However, in the medium with an intermediate pH of 5.5, both MFA and Eudragit® E PO are highly ionized, and the release was fast, complete, and stable within 24 h. These release behaviors could be to some degree applicable for immediate or enteric, but not for extended-release formulations.

Versatility of Juçara (Euterpe edulis) extracts as corrosion inhibitors of mild steel in different environments: 1 mol L−1 HCl and CO2-saturated formation water

Developing a sustainable and environmentally friendly inhibitor remains an essential and challenging goal for corrosion control. Here, different extracts from the same biomass (Juçara - Euterpe edulis) were applied as a new inhibitor for mild steel in different corrosive medium: 1 mol L−1 HCl (pH 0) and simulated CO2-saturated formation water (pH 5). Depending on the extraction process, the anticorrosive capacity of extracts may increase, a fact verified in gravimetric tests, reaching 94.4% maximum inhibition efficiency for the acidic medium (1000 mg L−1 of Juçara pulp in 48 h of immersion) and 86.1% inhibition efficiency for the saline medium (600 mg L−1 of Juçara pulp extract assisted by ultrasound in 24 h of immersion). Gravimetric tests, electrochemical tests, and surface and biochemical characterization analyses were carried out to better understand these extracts' performance. This work provides an interesting application of the same biomass effectively acting in different corrosive medium, depending on the extraction method.

Biorefinery of red seaweed Palmaria palmata for production of bio-based chemicals and biofuels

The seaweed Palmaria palmata was used as feedstock for production of chemical/fuel precursors (acetone, butanol, ethanol) and biogas. Palmaria palmata consists of xylan as major cell wall polysaccharide, as well as galactan and glucan. First, the biomass was subjected to acid hydrolysis at laboratory scale to solubilise fermentable sugars using acetic or hydrochloric acid as catalysts. Differences were observed in composition and amenability to hydrolysis of seaweeds from different harvests. Highest saccharification yields were obtained using HCl (pH 1.7, 120 °C, up to 80 % of xylose). Hydrolysates were fermented to acetone-butanol-ethanol by Clostridium beijerinckii reaching yields of 0.28 g products/g consumed sugars. The process by-products (solids after acetic acid hydrolysis and spent fermentation broth) were used as feedstocks for anaerobic digestion showing biogas yields between 310 and 650 L/kg dry organic material when mixed in different ratios with sugar beet pulp. Subsequently, the hydrolysis and fermentation processes were upscaled up to a 100-L pilot volume where nanofiltration was implemented to increase sugar concentration and remove salts. While high monomeric sugar yields were replicated during upscaling, fermentation inhibition was observed in the upscaled process. This paper shows Palmaria palmata to be a suitable feedstock for the co-production of bio-butanol and biogas and highlights process development needs to desalt and detoxify seaweed hydrolysates prior to fermentation.

Study of wet torrefaction and anaerobic digestion of empty fruit bunches for bioenergy production

Abstract In Malaysia, the palm oil industry generates vast amounts of solid and liquid waste, including empty fruit bunches (EFB) and palm oil mill effluent (POME). Finding efficient and environmentally friendly ways to manage and utilise this waste is crucial for sustainability. The research explores the utilisation of wet torrefaction in water for EFB, examining its impact on anaerobic digestion, specifically the dark fermentation (DF) process. The liquid product of torrefied EFB was further investigated as a substrate for biohydrogen production, employing innovative pre-treatment methods such as heat and acid on POME as the inoculum. This study focused on exploring the impact of temperature and holding time on the wet torrefaction of EFB prior to the dark fermentation process. Wet torrefaction was conducted at temperatures between 180 – 210°C and EFB: water ratio of 1:20 for 10 – 30 min, resulting in a mass yield of 52 – 54% and a chemical oxygen demand (COD) of 19.7 – 25.4 g/L COD. The chosen conditions (210°C for 30 min) demonstrated the lowest COD, validating the potential of torrefied liquid EFB for biohydrogen production. Dark fermentation was carried out at 37°C for 5 days, exploring various inoculum pretreatment parameters, including heat (80°C for 1 hr) and acid treatment (HCL pH 2-4). Liquid torrefied EFB with heat treatment inoculum exhibited the highest biohydrogen yield of 5.8 Nml, a notable 18% increase compared to the control. Through optimisation of parameters and effective waste management strategies, wet torrefaction and dark fermentation of EFB and POME emerge as promising approaches for sustainable biomass utilisation and renewable energy generation.

Coproduction of hydrogen peroxide and formic acid as potential hydrogen-carrier through photocatalytic reformation of sacrificial chemical

This study explores the challenges to photo-reforming sacrificial chemicals into beneficial by-products while improving photocatalytic activity in H2O2 production by addressing several issues. The resorcinol-formaldehyde/graphitic carbon nitride composite (RF0.2GCN) with nanosheet-like RF morphology achieved a higher degree of surface-to-surface contact through -C-NH-CH2- and -NH-CH-OH than the nanosphere (RF0.8GCN). The RF0.2GCN produced H2O2 at 325.2 µg g−1 s−1 in the presence of oxalic acid (OA) at pH 2.1 with apparent quantum yield (AQY) of 12.7 %. The conduction band position potential was +0.54 VNHE, which is thermodynamically unfavorable for H+/H2 (E°: 0.00 VNHE) and O2/·O2- (E°: −0.046 VNHE) reaction and also inhibits the decomposition of H2O2 (H2O2/·OH, E°: +0.39 VNHE). Furthermore, the decomposition of OA formed formic acid (FA) at 82 % selectivity and concurrent CO2·- formation could promote electron density in the conduction band via its electron-donating ability·H2O2 was purified by isolating FA using anion exchange resin, and FA was recovered by desorption from the resin using HCl (pH 3).

Drug Crystal Precipitation in Biorelevant Bicarbonate Buffer: A Well-Controlled Comparative Study with Phosphate Buffer.

The purpose of the present study was to clarify whether the precipitation profile of a drug in bicarbonate buffer (BCB) may differ from that in phosphate buffer (PPB) by a well-controlled comparative study. The precipitation profiles of structurally diverse poorly soluble drugs in BCB and PPB were evaluated by a pH-shift precipitation test or a solvent-shift precipitation test (seven weak acid drugs (pKa: 4.2 to 7.5), six weak base drugs (pKa: 4.8 to 8.4), one unionizable drug, and one zwitterionic drug). To focus on crystal precipitation processes, each ionizable drug was first completely dissolved in an HCl (pH 3.0) or NaOH (pH 11.0) aqueous solution (450 mL, 50 rpm, 37 °C). A 10-fold concentrated buffer solution (50 mL) was then added to shift the pH value to 6.5 to initiate precipitation (final volume: 500 mL, buffer capacity (β): 4.4 mM/ΔpH (BCB: 10 mM or PPB: 8 mM), ionic strength (I): 0.14 M (adjusted by NaCl)). The pH, β, and I values were set to be relevant to the physiology of the small intestine. For an unionizable drug, a solvent-shift method was used (1/100 dilution). To maintain the pH value of BCB, a floating lid was used to avoid the loss of CO2. The floating lid was applied also to PPB to precisely align the experimental conditions between BCB and PPB. The solid form of the precipitants was identified by powder X-ray diffraction and differential scanning microscopy. The precipitation of weak acids (pKa ≤ 5.1) and weak bases (pKa ≥ 7.3) was found to be slower in BCB than in PPB. In contrast, the precipitation profiles in BCB and PPB were similar for less ionizable or nonionizable drugs at pH 6.5. The final pH values of the bulk phase were pH 6.5 ± 0.1 after the precipitation tests in all cases. All precipitates were in their respective free forms. The precipitation of ionizable weak acids and bases was slower in BCB than in PPB. The surface pH of precipitating particles may have differed between BCB and PPB due to the slow hydration process of CO2 specific to BCB. Since BCB is a physiological buffer in the small intestine, it should be considered as an option for precipitation studies of ionizable weak acids and bases.

Carbon Nanotube Modified Glassy Carbon Electrodes for on‐line and off‐line in vitro Therapeutic Equivalence Assessment of Paracetamol Tablets

AbstractIn vitro bioequivalence assessment of paracetamol tablets was carried out by differential pulse voltammetry (DPV) and amperometry using a multiwalled carbon nanotube modified glassy carbon electrode (GCE/MWCNT). For the DPV developed method, samples were collected from the USP paddle apparatus, while amperometric measurements were carried out in situ. The DPV method was validated in three supporting electrolytes (per in vitro bioequivalence guidelines) by measuring the recovery from standard solutions and paracetamol tablet solutions, while precision was evaluated through the RSD (n=6). In HCl pH 1.2 solution the LOD and LOQ were 48 nM and 160 nM, respectively and the linear range was between 0.18–2.2 μM. In acetate buffer pH 4.5 the LOD and LOQ were 15 nM and 51 nM, respectively and the linear range was between 88 nM–880 nM. And in phosphate buffer pH 6.8 the LOD and LOQ were 4.6 nM and 15 nM, respectively and the linear range was between 88 nM–880 nM. Recovery values were between 95 and 105 % and precision values were less than 5 %. Results showed that both methods were effectively applied for the analysis of samples.

A simple and rapid HPLC-UV method for the determination of valproic acid in human plasma using microwave-assisted derivatization with phenylhydrazine hydrochloride

This study presents an efficient high-performance liquid chromatography with ultraviolet detection (HPLC-UV) method for monitoring valproic acid (VPA) level in human plasma. This method is distinguished by its simplicity, cost-effectiveness, and rapid execution, addressing the limitations associated with other advanced analytical techniques like liquid chromatography-mass spectrometry (LC-MS), gas chromatography-mass spectrometry (GC-MS), and immunoassays, which are generally complex and costly for routine application. A challenge in analyzing VPA is its non-linear protein binding profile and the absence of a chromophore in its structure, making direct detection difficult. To overcome this, the study developed an efficient HPLC-UV for VPA determination in human plasma, utilizing a simplified and rapid microwave-assisted derivatization process. Due to the lack of a chromophore in VPA structure, this work developed a microwave-assisted derivatization of VPA using phenylhydrazine hydrochloride (PH HCl). The process optimization was achieved at 450 W for 50 s, facilitating effective HPLC-UV detection. The derivatized product was characterized using 1H nuclear magnetic resonance (NMR) and Fourier transform infrared spectrometer (FT-IR). The derivative, identified as (Z)-N-phenyl-2-propylpentanehydrazonic acid, demonstrated specificity in plasma analysis with no detectable interference. The method exhibited a linear response for VPA concentrations ranging from 30 to 150 μg/mL, with a correlation coefficient exceeding 0.99. Recovery varied between 86.7% and 107%, with a maximum coefficient of variation (CV) of 10.0%. The findings suggest that the microwave-assisted derivatization technique substantially improves the feasibility and cost-effectiveness of HPLC-UV for the analysis of VPA in plasma. This method provides a viable alternative to conventional HPLC methodologies, offering a balance of efficiency and economic practicality for VPA quantification.

Formulation and Development of Novel Sulfasalazine Bilayer Tablets for The Treatment of Arthritis Associated With IBD: In-vitro and In-vivo Investigations

Sulfasalazine needs frequent daily dosing and the administration of numerous tablets per day pose challenges to patient compliance, contributing to increased adverse effects and difficulties in disease control. These inconveniences result in less effective treatment for arthritis associated with inflammatory bowel disease i.e. ulcerative colitis etc. To improve drug bioavailability, a delayed-release mechanism that releases the drug at the colon is necessary. To develop and optimize colon-targeted controlled release bilayer tablets coated with pH-dependent polymers. The bilayer tablets containing the immediate release part and sustained release part were developed. The tablets were coated with enteric-coated with Eudragit® S-100 and l-100 to achieve release in the colon. Granule properties and tablets were evaluated. The physicochemical parameters of the tablets were evaluated including, stability study, and drug release in 0.1 N HCl (pH 1.2), pH 6.8 phosphate buffer, pH 7.4 phosphate buffer for 2, 1, and up to 24 h respectively. Radiographic imaging and in vivo pharmacokinetic studies were also done in Rabbits. The bilayer tablets containing immediate and sustained release were successfully developed for the colon targeting. The granule properties were found within the acceptable range indicating good flow properties. The physicochemical properties of the tablets were also found acceptable. The tablets did not show release in 0.1 N HCl and 6.8 phosphate buffer but drug release was found under control in the 7.4 pH buffer. Sulfasalazine coated bilayer tablets were found stable and no significant changes were observed in the stability studies. Based on the X-ray studies, the formulated tablet remained discernible in the stomach, small intestine, and colon for a duration of up to 24 h. Finally, by the 32nd hour, the tablet was no longer visible in the X-ray examination, leading to the conclusion of complete drug release. The drug concentration in plasma remained within the therapeutic range for up to 24 h in vivo. These novel formulations present substantial advantages, providing prolonged targeted drug release and reducing systemic adverse effects. The results suggest promising potential for treating arthritis in Inflammatory bowel disease (IBD) patients, offering a solution to current delivery systems.

Preparation and Evaluation of a Self-Emulsifying Drug Delivery System for Improving the Solubility and Permeability of Ticagrelor.

Ticagrelor (TCG) is a BCS class IV antiplatelet drug used to prevent platelet aggregation in patients with acute coronary syndrome, having poor solubility and permeability. The goal of this study was to develop a self-nanoemulsifying drug delivery system (SNEDDS) of TCG to improve its solubility and permeability. The excipients were selected based on the maximum solubility of TCG and observed by UV spectrophotometer. Different combinations of oil, surfactant, and co-surfactant (1:1, 2:1, and 3:1) were used to prepare TCG-SNEDDS formulations, and pseudo-ternary phase diagrams were plotted. The nanoemulsion region was observed. Clove oil (10-20%), Tween-80 (45-70%), and PEG-400 (20-45%) were used as an oil, surfactant, and co-surfactant, respectively. The selected formulations (F1, F2, F3, F4, F5, and F6) were analyzed for ζ potential, polydispersity index (PDI), ζ size, self-emulsification test, cloud point determination, thermodynamic studies, entrapment efficiency, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), in vitro dissolution, ex vivo permeation, and pharmacodynamic study. The TCG-SNEDDS formulations exhibited ζ potential from -9.92 to -6.23 mV, a ζ average of 11.85-260.4 nm, and good PDI. The in vitro drug release in phosphate buffer pH 6.8 from selected TCG-SNEDDS F4 was about 98.45%, and F6 was about 97.86%, displaying improved dissolution of TCG in 0.1 N HCl and phosphate buffer pH 6.8, in comparison to 28.05% of pure TCG suspension after 12 h. While the in vitro drug release in 0.1 N HCl from F4 was about 62.03%, F6 was about 73.57%, which is higher than 10.35% of the pure TCG suspension. In ex vivo permeability studies, F4 also exhibited an improved apparent permeability of 2.7 × 10-6versus 0.6708 × 10-6 cm2/s of pure drug suspension. The pharmacodynamic study in rabbits demonstrated enhanced antiplatelet activity from TCG-SNEDDS F4 compared to that from pure TCG suspension. These outcomes imply that the TCG-SNEDDS may serve as an effective means of enhancing TCG's antiplatelet activity by improving the solubility and permeability of TCG.

Effect of Croscormellose Sodium in Sustained Release Layer of Valsartan in Bilayer Tablet with Clopidogrel as Immediate Drug Release and Valsartan as Sustained Drug Release

The aim of the study was to design and evaluate bilayer tablets of clopidogrel as immediate release and quick relief and valsartan for sustained release and check the effect of croscarmellose sodium (2%) in Carbopol for sustained release action. Bilayer tablets was prepared using direct compression method. Super disintegrants such as Crospovidone, Croscarmellose sodium were evaluated for immediate release of clopidogrel. Polymers HPMC K4, guar gum, ethyl cellulose and carbopol for controlling release of Valsartan. The compressed bilayer tablets were evaluated for weight variation, thickness, hardness, friability, drug content and in vitro drug release in 0.1N HCl and phosphate buffer pH 6.8. All the pre and post compression parameters were found to be within the acceptable limits. The formulations were optimized based on results of dissolution and formulations CF5 for immediate release &amp; VF11 for sustained release. VF11 was formulated with addition of superdisentigrant and showed better controlled release and dissolution similar to VF8. The release kinetics of Valsartan was subject to curve fitting analysis in order to identify the best fit kinetic model. The regression analysis proves that VF11 follow first order release and drug release by diffusion process based on Fick’s law of diffusion. The data for stability studies infer no considerable change in drug content, dissolution rates and other quality control test were within limits.&#x0D; Keywords: Bilayer tablets, clopidogrel, valsartan, direct compression method.

Adsorbent effectiveness of α-cellulose/humatic acid with epichlorohydrin cross-linking agent on methyl orange dye

Adsorption of methyl orange (MO) using epichlorohydrin cross-linked humic acid/cellulose composite has been carried out. This study aims to synthesize epichlorohydrin cross-linked humic acid/cellulose composites, determine the optimum pH, contact time, and initial concentration and study MO desorption. The adsorbent production begins with the isolation of cellulose from empty palm oil bunches (EFB) obtained from North Sumatra and the isolation of humic acid from peat soil obtained from Rawa Pening. Then humic acid was cross-linked to cellulose in an alkaline solution (NaOH), then epichlorohydrin was added as a cross-linking agent while heating at 600C for 2 hours. Epichlorohydrin cross-linked humic acid/cellulose adsorbents (AH/Cell-ECH) were further characterized using FTIR, XRD and SEM spectroscopy. MO solutions before and after adsorption were analyzed using UV-Vis spectrophotometry. MO desorption studies used HCl pH 4, 0.1 and 1.0 M NaCl and 40% and 60% ethanol. FTIR characterization showed that the AH/Sel-ECH adsorbents had active groups, including –OH, -C=O, and –COOH. Characterization using XRD showed diffraction peaks in the 2θ region around 11.41, 20.25, 22.55, and 42.66o, indicating the presence of galactose, xylose, glucose and polysaccharide phases. The SEM-EDX results showed that the surface of the adsorbent had non-uniform pore sizes, and the surface morphology tended to be clean and free of debris. It indicated the presence of C, O, and N elements in AH/ECH-cells and S, N elements after MO adsorption. The optimum interaction of AH/Sel-ECH with MO occurred at pH 2 with 150 mg/L MO, and a contact time of 120 minutes was obtained. MO adsorption by AH/ECH-cells followed a pseudo-second-order kinetics model and the Freundlich isotherm with an MO adsorption capacity of 9.84 x 10-5 mmol/g, respectively. Desorption studies showed that 60% ethanol was the most effective solution for desorption of MO.

Evaluation of an eco-friendly botanical extract against Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) and its composition

The red flour beetle, Tribolium castaneum (Coleoptera: Tenebrionidae), is one of the most damaging grain insect pests in the storage products industry. The acquired resistance to synthetic pesticides and the high toxicity of these compounds on non-target organisms have led to an increase in the search for biopesticides. Thus, the present study aimed to analyze, for the first time, the chemical composition of the extract of Crotalaria stipularia Desv. seeds and its insecticidal activity against T. castaneum adults. Therefore, the crude extract (5 % w/v) of C. stipularia seeds was performed in a 50 mM Tris − HCl pH 8.0. Lectin and secondary metabolites such as flavones, flavonols, xanthones and saponins were detected in the extract. The extract (10 % w/v) of C. stipularia caused 100 % mortality against T. castaneum insects and exhibited moderate deterrent activity, resulting in a 70 % reduction in food consumption compared to their normal intake. Furthermore, the aqueous extract exerted antinutritional effects, interfering with the metabolism of proteins, cholesterol, triglycerides and carbohydrates, and abolished the hatching of eggs of the treated insects. The phytotoxicity test revealed that the extract of C. stipularia is not toxic to non-target organisms, as it did not affect the germination of lettuce (Lactuca sativa) seeds. These results support the search for integrated management strategies for the control of T. castaneum using a new biomaterial obtained from C. stipularia seeds.

Bicarbonate buffer dissolution test with gentle mechanistic stress for bioequivalence prediction of enteric-coated pellet formulations

This study aimed to develop a dissolution test that can predict the bioequivalence (BE) of enteric-coated pellet formulations. The original duloxetine hydrochloride capsule (reference formulation (RF); Cymbalta® 30 mg capsule) and four generic test formulations (two capsules (CP) and two orally disintegrating tablets (OD)) were used as model formulations. Clinical BE studies were conducted on 24–47 healthy male subjects under fasting conditions. Dissolution tests were performed using a compendial paddle method (PD) (paddle speed: 50 rpm) and a flow-through cell method (FTC) (flow rate: 4 mL/min). For a further test, cotton balls were added to the vessel to apply gentle mechanistic stress to the formulations, and paddle speed was reduced to 10 rpm (paddle with cotton ball method (PDCB)).All the dissolution tests were conducted with 0.01 M HCl (pH 2.0) for 0.5 h followed by 10 mM bicarbonate buffer solutions (pH 6.5) for 4 h. One each of the two CP and two OD showed BE with RF. PDCB was able to discriminate between BE and non-BE formulations, while this was not possible with PD and FTC. In PDCB, the cotton balls intermittently moved the pellets near the vessel bottom. PDCB is useful for predicting BE during formulation development.

B-035 Maintaining the Analytical Performance of Calcium and Phosphorus in 24-hour Urine Without Addition of 6n hcl in the Pre-Analytical Process

Abstract Background The measurements of Calcium (Ca) and Phosphorus (P) in 24-hour urine samples are associated with the evaluation of hyperparathyroidism, renal tubular acidosis, and monitoring of Falconi Syndrome and Nephrolithiasis. The aim is to demonstrate the maintenance of analytical performance without the addition of 6N hydrochloric acid (HCl) in the pre-analytical process. Methods The study was divided into stages and carried out for both analytes. In the first stage, correlation tests were performed on 40 samples with and without HCl within the range of linearity. Imprecision was processed at 3 clinically relevant concentrations for 5 days, repeated 5 times. In the second stage, stability testing of Ca and P was performed on 7 samples over 5 days, without HCl (pH 5–6.7), with HCl (pH &amp;lt; 3), alkalized (pH &amp;gt; 8), and neutral (pH 7–7.5). In the last stage, interferent testing was performed on 286 samples, where pH was measured after collection and after acidification with 200uL of HCl. A pH meter and pH strips were used to measure pH, and a Siemens® - Advia 2400 equipment was used for analytical measurement of Ca and P. Results In the correlation results, the variance test for both analytes resulted in F-test: 1.01 &amp;lt; 1.69, the difference analysis was less than 2.02, correlation coefficient and Bias% of 1.00 and 0.55 for Ca and 0.99 and 0.27 for P, respectively. Total error (TE) obtained for Ca was 9.69 and 9.41, lower than the allowed TE for both analytes. The repeatability and intralaboratory imprecision of the three levels of each analyte were less than 13.8% for Ca and 9.0% for P. There was 100% correlation of the results when the analyses were performed with samples at pH up to 7; at pH values &amp;gt; 7, the concentrations decreased by 60%. All 268 samples with different pH values, subjected to 200uL of HCl, were suitable for Ca and P measurement with pH below 5.7. Conclusions Samples with a pH greater &amp;gt;or = to 7 necessarily need to be acidified with HCl 6N. There is no analytical alteration if all samples in the routine of urinary Ca and P are submitted to 200uL of HCl 6N, even the most alkaline samples. The non-provision of preservative containers to patients reduces the risk of accidents, costs, and the need for legal licenses for handling in healthcare facilities.

Fexofenadine Hydrochloride Dispersible Tablets: A Taste Masking Strategy using Ion Exchange Resin

The pediatric population is more sensitive to allergies. Fexofenadine hydrochloride (FXD-HCL), a non-sedative antihistaminic drug, was chosen to create taste-masked patient-compliant pediatric dispersible tablets. Due to its bitter taste, fexofenadine hydrochloride is unsuitable for the formulation of dispersible tablets; therefore, Kyron T-134®, cation exchange resin was used to form a taste-masked complex with the drug to overcome its bitterness. The FXD HCL-resin complex was prepared using a kneading method and the complexation was confirmed by differential scanning calorimetry and FTIR studies. The FXD HCL-resin complex was evaluated for flow properties, degree of bitterness, assay and release study. Dispersible tablets were formulated by using a co-processed excipient, Granfiller-D211® containing croscarmellose sodium and crosspovidone, microcrystalline cellulose and mannitol. 22 factorial designs with two replicates optimized the dispersible tablets. The tablets, prepared using the direct compression technique on a single-stroke tablet compression machine, were elegant in appearance. Various pre and post-compression tests were conducted on all formulations. The tablets of hardness 3.5 kg/cm2 showed friability, disintegration time, assay within the compendial limit and showed immediate release of a drug (NLT 60% in 10 min and NLT 80% in 30 minutes) in 0.001 N HCl (pH 3). The DSC thermogram indicated partial amorphization of the FXD HCL. Dispersible tablets of fexofenadine hydrochloride and Granfiller-D®211 at 1:4 proportion was stable for one month at ambient and accelerated storage conditions.

Comparative UV Spectroscopic Method Analysis and Validation for Estimation of Rifaximin in Pharmaceutical Preparation

In the present research work the absorption characteristics of rifaximin was studied and validated in different solvents in visible region for its quantitative estimation in bulk and dosage forms by UV spectrophotometric method. The solution of Rifaximin were prepared in 0.1N HCL (pH 1.2), Phosphate buffer (pH 6.8) &amp; Phosphate buffer (pH 7.4) and showed maximum absorption at wavelength 439 nm, 440 nm &amp; 433 nm in respective solvents. The drug obeyed Beer–Lambert’s law in the concentration range of 2, 4, 6, 8, 10 µg/mL with coefficient of correlation (r2) of 0.998. The estimation method was validated as per the ICH guidelines. Statistical analysis proved that the methods are repeatable and specific for the estimation of the said drug. These methods can be adopted in routine analysis of Rifaximin in bulk or tablet dosage form.&#x0D; Keywords: Rifaximin, 0.1N HCL, phosphate buffer, UV spectrophotometer.

Modification of Cassava Starch With Combination of Steaming and Acid Hydrolysis and Use as Encapsulant in Nanoencapsulation of Cocoa Leaf Crude Extract (Theobroma cacao L)

The utilization of native cassava starch in the food industry is limited. It needs a modified process to increase its utilization. This study aimed to evaluate the effect of a combination of steaming and acid hydrolysis and determine the best temperature and hydrolysis time that is suitable to apply as an encapsulant in the nanoencapsulation process of cocoa leaf crude extract. Modification of cassava starch used 50 ℃, 60 ℃, and 70 ℃ temperatures for 30, 60, and 90 minutes with HCl pH 1. The result showed that modified cassava starch produced from a combination of steaming and acid hydrolysis at 70℃ for 30 minutes has the best specifications with 60.48% solubility, 12.38% hygroscopicity, pasting profile (PV=48; BV=3; FV=66; SV=21). Then, it is combined with Arabic gum and used in the nanoencapsulation process using spray drying. This study showed that encapsulation can protect phenolic compounds of cocoa leaf crude extract resulting brownish-red color surrounded by a black circle. Nanocapsule powder has 13.56% moisture content, 350.3 nm particle size, 16.93 zeta potential, and 84.30% encapsulation efficiency. The combination of steaming and acid hydrolysis at 70 ℃ for 30 minutes produces modified cassava starch which is suitable for use as an encapsulant in the nanoencapsulation process of crude extract of cocoa leaves.