Sodium Lauryl Sulfate Solution Research Articles

Validation of High-Performance Liquid Chromatography method for the determination of doxorubicin in proliposomal drug delivery system formulation

The objective of this study develop a novel proliposome formulation containing Doxorubicin (Dox) and was to validate sensitive and selective reversed-phase high-performance liquid chromatographic (HPLC) method for the evaluation of Dox concentrations of proliposome formulation. The samples were chromatographed on C18 column (Zorbax Eclipse Plus 5µm 4.6 x 250 mm) using a mobile phase with Sodium Lauryl Sulphate solution:Acetonitrile (%50:%50) and detected 254 nm. Linearity was confirmed in the concentration range 10.0–75.0 µg/mL. Specificity, linearity, working range, LOD, LOQ, accuracy, precision, robustness and system suitability studies were done from HPLC validation parameters. Liposome formulation containing Dox was developed by pH gradient method then proliposome formulation was developed with lyophilisation technique. The developed HPLC method, the encapsulation capacity (EE%) was found to be 90%±0.5 and the drug loading capacity (DL%) was found to be 100.0%±0.3. In addition, in vitro release studies and stability study results were evaluated with validated HPLC method. It was observed that developed Dox-proliposome formulation increased Dox release at pH 5.5, pH 6.5 and pH 7.5 by 23.9%, 30.2% and 14.8%, respectively, compared to commercial product. The result of F2 test performed in pH 7.5 media was 51.4%. According to the results of the physicochemical tests performed within the stability studies, it was observed that there was no significant change at the end of 12 months. These results show that the HPLC method developed, and validation study performed are important and applicable in the development, characterization, in vitro release and stability studies of the novel proliposome formulation.

Nonisothermal Evaporation of Sessile Drops of Aqueous Solutions with Surfactant

In recent decades, electronic devices have tended towards miniaturization, which necessitates the development of new cooling systems. Droplet cooling on a heated wall is effectively used in power devices with high heat flux densities. The use of a surfactant leads to an increase in the diameter of the wetted spot and the rate of droplet evaporation. Despite the wide interest and numerous works in this area, there are still unexplored questions regarding the influence of surfactant and wall temperature on convection, of nonisothermality, and of the decrease in the partial pressure of vapor with increasing surfactant concentration. This work experimentally studies the effect on the rate of droplet evaporation of wall temperature in the range 20–90 °C and of the concentration of surfactant in an aqueous solution of sodium lauryl sulfate (SLS) from 0 to 10,000 ppm. It is shown for the first time that an inversion of the evaporation rate related to the droplet diameter occurs with increasing wall temperature. The influence of key factors on the evaporation of a water droplet with SLS changes with temperature. Thus, at a slightly heated wall, the growth of the droplet diameter becomes predominant. At high heat flux, the role of nonisothermality is predominant. To determine the individual influence of the surfactant on the partial pressure of water vapor, experiments on the evaporation of a liquid layer were carried out. The obtained results and simplified estimates may be used to develop existing calculation models, as well as to optimize technologies for cooling highly heated surfaces.

A Simple And Validated Spectrophotometric Analysis Method For The Hydrophobic Drug Fenofibrate In Natural Oils

Objective: In this work, sodium lauryl sulfate (SLS) was used to present a simple spectrophotometry approach to more accuratequantification of fenofibrate (FENO) concentration in five natural oils (soybean oil, lemon oil, black seed oil, cardamom oil, and garlicoil). In the published work either organic solvent was used which may result in false results due to the dissolving of oil by organicsolvent, or high-performance liquid chromatography (HPLC) was utilized, which is a sophisticated instrument that may not be availableat every research facility.Methods: construction of a calibration curve using a series of FENO concentrations added to 0.5% SLS phosphate buffer solution andmeasuring the absorbance by spectroscopy at 289 nm. The drug samples in different oils were diluted with 0.5% SLS phosphate buffersolution prior to direct reading by spectroscopy. According to the International Conference on Harmonization requirements, the methodwas validated regarding specificity, precision, accuracy, and determination range.Results: FENO gave absorbance maxima at 289 nm in 0.5% SLS solution, the beer’s law was obeyed in the range of 0.0125 to 0.05mg/ml. High linearity (in the scope of 10 - 125 mg, R2=1), highly specific, good accuracy (95- 104), precision (SD< 10%), and a widerange of detection, indicate validation of the procedure.Conclusion: the proposed method for FENO analysis is simple, fast, and promising for easy determination of FENO in bulk andpharmaceuticals.

Contaminant film thickness affects walkway friction measurements.

Walkway tribometers are used to measure available friction for evaluating walkway safety and pedestrian slip risk. Numerous variables can affect tribometer measurements, including the type and distribution of contaminants on the surface. Here, we quantified the effect of application method on contaminant film thickness, and the effect of film thickness on tribometer measurements on the four reference walkway surfaces used in ASTM F2508-16e. Distilled water, 0.05% sodium lauryl sulfate (SLS) solution, and 0.04% Triton X-100 solution were poured, squirted, and sprayed onto the surfaces to quantify their naturally occurring film thicknesses. These application methods had a significant effect on the resulting film thickness (p < 0.038), with the pour method consistently generating the thickest films and the spray method generating the thinnest films. We then quantified the effect of film thickness for the three contaminants (thickness range 0.3–3.3 mm) on the friction measurements of three common tribometers (Mark IIIB, English XL, and BOT 3000E) on each reference surface. A separate ANOVA was used for each of the 3 × 4 × 3 = 36 combinations of tribometer, surface, and contaminant. Friction measured with the Mark IIIB decreased with increasing film thickness on one surface across all three contaminants and on a second surface with the SLS contaminant. Friction measured with the BOT 3000E was sensitive to film thickness on two surfaces with water and one surface with Triton. The XL was unaffected by contaminant film thickness. Overall, despite significant differences in film thickness with contaminant application method, friction measurements were either insensitive to film thickness or varied only a small amount in all cases except for the Mark IIIB on the roughest surface. Film thickness did not alter the relative slip resistance of the four ASTM F2508 reference surfaces.

The Effect of Variation of Latex Mixed Storage Time Polystyrene and Natural Rubber Concentrate Latex on the Stability of the Emulsion by Using Emulsifier Sodium Lauryl Sulfate

Preparation of latex polystyrene with emulsifier ammonium lauryl sulfate (ALS) has been carried out by dissolving styrofoam (foam polystyrene) in toluene (30/70). And then polystyrene solution was mixed with aquadest, at ratios polystyrene and aquadest (v/v) were 90:10, 70:30, 50:50, 70:30, and 10:90 then added 10 mL of sodium lauryl sulfate (NLS) solution at concentrations 30%. The characterizations of the latex polystyrene included the stability determination during storage by density measurement and the determination of particle sizes and forms by microscopic optic observation. The results show that latex polystyrene ratio 90:10 is the most stable with density value constant during storage, are 0,848 g/mL for 30%. The particle sizes average is 1,56 mm with the distribution particle sizes decreasing as latex is 8,3 mm. Photomicrograph microscope optic shows that latex polystyrene NLS 30% has familiar particle forms and sizes

Influence of admixtures on the characteristics of aqueous foam produced using a synthetic surfactant

Foam characteristics, including density, stability, and texture, influence the properties of end products like foamed concrete. The present work investigates the individual and combined influence of xanthan gum and low-cost sodium-based admixtures (NaOH, NaCl, and Na2CO3) on the viscosity of sodium lauryl sulfate (SLS) foaming solution and the foam characteristics. Where xanthan gum induced its characteristic pseudo-plastic behavior to the foaming solution, the addition of sodium-based admixtures did not affect the Newtonian behavior of the SLS solution. The addition of sodium-based admixtures elevated the critical turbidity and Krafft temperature of the surfactant solution. Xanthan gum substantially reduced the liquid drainage and improved stability to a great extent. However, the increment in foam density was more gradual with increasing xanthan gum dosage, following an increase in lamella thickness. Sodium-based admixtures significantly increased the density of foam while reducing the bubble sizes. Further, the SLS solution admixed with xanthan gum and sodium-based admixture resulted in foam with properties intermediate to the foams stabilized with individual admixtures. The resulting foam had a higher density and a smaller mean bubble size than unstabilized or xanthan gum stabilized foam. In contrast, the stability was more increased compared to unstabilized or sodium-based admixture stabilized foam.

Green Solvent Assisted UV-Spectrophotometric Method for Estimation of Rosuvastatin in Bulk and Pharmaceutical Dosage Forms

Objectives: The goal of this study is to create and test a UV-Spectrophotometric method for estimating Rosuvastatin in bulk and pharmaceutical dosage forms utilizing a green solvent. Method: Development of UV-Spectrophotometric method was carried out by using 2% Sodium Lauryl Sulfate solution as green solvent. Rosuvastatin was detected at a wavelength of 242nm. According to ICH guidelines, the developed technique was verified in terms of linearity, precision, repeatability, limit of detection, limit of quantification, accuracy, and robustness. Rosuvastatin in pharmaceutical dose forms was successfully estimated using a newly developed and verified approach. Results: Rosuvastatin has a maximum absorption wavelength of 242nm. In the concentration range of 5-25µg/ml, Beer's law was followed. The detection and quantification limits were found to be 1.58µg/ml and 4.79µg/ml, respectively. The recovery of Rosuvastatin Calcium in tablet form was found to be between 97 and 102 percent. All of the precision and repeatability results fell within acceptable limits. Rosuvastatin was tested and found to be 98.88%. Conclusion: The method was found to be simple, environment friendly, reproducible and economical and can be used for routine analysis of Rosuvastatin in bulk and pharmaceutical dosage form. The 2% Sodium Lauryl Sulfate solution can be used as Green solvent.

Pharmaceutical cocrystals of Efavirenz: Towards the improvement of solubility, dissolution rate and stability

Efavirenz (EFV) is a Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTI) class of antiretroviral drug that is included in antiretroviral therapy to treat Human Immunodeficiency Virus (HIV) patients to increase the life-span by avoiding them to develop Acquired Immune Deficiency Syndrome (AIDS). One of the major drawbacks of EFV is its solubility in purified water (0.093 mg/L). In the present work, two cocrystals of EFV using tartaric acid (TAR) and adipic acid (ADP) as coformers that are Generally Recognized as Safe (GRAS) are reported. Both the EFV-TAR and EFV-ADP cocrystals were developed using slow solvent evaporation technique and further characterization of developed cocrystal structures was done by Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), Differential scanning calorimetry (DSC) and Powder x-ray diffraction (PXRD) techniques. The SEM photomicrographs indicated that the EFV-TAR cocrystals were in needle shape with smooth surface. Its length ranged from 100 to 300 µm. The EFV-ADP cocrystals were found to be flaky needle shape with rough surface bearing irregular edges whose length ranged about 50–400 µm. The FT-IR spectra of both developed cocrystals confirmed the formation of a hydrogen bond between EFV and coformers by indicating a notable shift in –CO functional group. The DSC and PXRD studies were further confirmed the successful development of a novel crystalline form (Cocrystal). The solubility (25 ± 0.5 °C) of EFV-TAR and EFV-ADP cocrystals were found to be 163 and 107 μg/mL respectively, whereas pure EFV showed 94 μg/mL. The dissolution rate (37 ± 0.5 °C) of EFV-TAR and EFV-ADP cocrystals in 1% sodium lauryl sulphate (SLS) solution demonstrated 1.4 and 1.2 times increment respectively, compared to the pure EFV. The developed EFV-TAR and EFV-ADP cocrystals were found to stable for 6 months in ambient conditions (25 ± 2 °C, 60 ± 5% relative humidity).

Oral Nanoemulsion of Fenofibrate: Formulation, Characterization, and In Vitro Drug Release Studies.

Nanoemulsions (NMs) are one of the most important colloidal dispersion systems that are primarily used to improve the solubility of poorly water soluble drugs. The main objectives of this study were, first, to prepare an NM loaded with fenofibrate using a high shear homogenization technique and, second, to study the effect of variable using a central composite design. Twenty batches of fenofibrate-loaded NM formulations were prepared. The formed NMs were subjected to droplet size analysis, zeta potential, entrapment efficiency, pH, dilution, polydispersity index, transmission electron microscopy (TEM), Fourier transform infrared spectrophotometry, differential scanning calorimetry (DSC), and in vitro drug release study. Analysis of variance was used for entrapment efficiency data to study the fitness and significance of the design. The NM-7 batch formulation demonstrated maximum entrapment efficiency (81.82%) with lowest droplet size (72.28 nm), and was thus chosen as the optimized batch. TEM analysis revealed that the NM was well dispersed with droplet sizes <100 nm. Incorporation of the drug into the NM was confirmed with DSC studies. In addition, the batch NM-7 also showed the maximum in vitro drug release (87.6%) in a 0.05 M sodium lauryl sulfate solution. The release data revealed that the NM followed first-order kinetics. The outcomes of the study revealed the development of a stable oral NM containing fenofibrate using the high shear homogenization technique. This approach may aid in further enhancing the oral bioavailability of fenofibrate, which requires further in vivo studies.

Studies of the pore space of the UPM-K, UAM-50, UAM-100 composite ultrafiltration membrane

The development of methods for assessing the distribution of pores by radii (or diameters) and studying the microstructure of the surface of a membrane partition is an urgent task. The authors of the paper carried out experimental studies of the pore diameter distribution for the UPM-K ultrafiltration membrane, determined the porosity and hydrodynamic permeability of the UAM-50, UAM-100 membranes. The analysis of the experimental results showed that the UPM-K ultrafiltration membrane had an average pore diameter of 54 nm. The UAM-50 and UAM-100 membranes were characterized by an asymmetric structure (an active layer (dense) and a porous substrate), while the pores were 2.5–40 and 10–40 nm in size, respectively. The experiments on the study of the hydrodynamic permeability of UAM-50, UAM-100 ultrafiltration membranes when separating a solution of sodium lauryl sulfate showed that the kinetic response curves of the “membrane-solution” system were conventionally divided into two stages. The first stage of the process was faster and lasted only a few minutes. After 7.8 and 13.05 min, the hydrodynamic permeability decreased by ~ 27 %, 7 %, which was due to structural changes in the cellulose acetate layer under the action of mechanical load (transmembrane pressure). The second stage was slower – with a duration of ~ 33 and 60 min and a decrease in hydrodynamic permeability by 41 % and 11 %. Based on the analysis of the approximating function, the rate constants of the membrane separation of solutions and the empirical coefficients of the equation are found.

Formulation of Face-Wash from Coconut (&lt;i&gt;Cocos nucifera (L.))&lt;/i&gt; Oil in Ben Tre Province, Vietnam

Today, the need for human care and beauty is increasing. The use of personal care products, especially those from nature, has been given special attention by consumers. With diverse features and good effects on the human body, especially the skin, coconut oil is being cared for by many manufacturers. With the aim of diversifying personal care products from coconut oil, this research has initially achieved positive results. Soap saponified as raw soap is considered to have good cleaning effect (better than sodium lauryl sulfate solution (SLS) when diluted to the same concentration). The combination of 10% crude soap and 4% sodium lauryl ether sulfate (SLES) surfactants formulate cleansing products with effective cleansing properties. Ingredients auxiliary cleaners, moisturizing, and softening, antioxidants are added with the appropriate content to improve the disadvantages of raw soap. The personal care products that have been studied have the potential to enter the cosmetic market and attract many consumers.

Influences of alkanes on the phase behaviors of system of cationic–anionic surfactants

The effects of three straight-chain alkanes (n-pentane, n-heptane, and n-octane) on the phase behaviors of aqueous solutions of sodium lauryl sulfate and hexadecyl trimethylammonium bromide with additives of 1-hexanol and NaBr were examined. Phase diagram and polarization detection implied that the alkanes were located in the hydrophobic region of ordered aggregates while 1-hexanol and NaBr were located in the hydrophilic region, respectively, affecting the forces between surfactant molecules in the two regions. The length of alkanes was an important factor in determining the phase behaviors, especially the range and structure of liquid crystal (LC). Alkanes with shorter carbon chain are more efficient in formation of more and longer-range ordered LC structures. In addition, partial aqueous two phase (ATPS) was transformed into LC with the increase of temperature since higher temperatures provided energy for the further growth of LC.

Effect of Sodium Lauryl Sulfate (SLS) Applied as a Patch on Human Skin Physiology and Its Microbiota

In this study, we assessed the change in skin microbiota composition, relative abundance, and diversity with skin physiology disruption induced by SLS patch. Healthy women declaring to have a reactive skin were submitted to a 0.5% aqueous sodium lauryl sulfate solution application under occlusive patch condition for 24 h. Skin properties were characterized by tewametry, corneometry, and colorimetry and bacterial diversity was assessed by 16S rRNA sequencing. Analysis before and one day after SLS patch removal revealed an increase of skin redness and a decrease of stratum corneum hydration and skin barrier function. The relative abundance of taxa containing potential pathogens increase (Firmicutes: Staphylococcaceae; Proteobacteria: Enterobacteriaceae, Pantoea) while some of the most occurring Actinobacteria with valuable skin protection and repair capacities decreased (Micrococcus, Kocuria, and Corynebacterium). We observed an impaired skin barrier function and dehydration induced by SLS patch disturb the subtle balance of skin microbiota towards skin bacterial community dysbiosis. This study provides new insights on the skin bacterial composition and skin physiology simultaneously impaired by a SLS patch.

Comparative study of saponin for surfactant properties and potential application in personal care products

Surfactants are typically organic compounds containing hydrophobic and hydrophilic groups bearing polar and non-polar classes. Saponin is one of the surfactant classes present in the plant species with steroidal aglycone or triterpenoid and one or more chains of sugar characterized by its structure. Now days, consumers are becoming more aware of natural products associated with their physicochemical properties. Saponin's potential use as surfactant is caused by the combination of a non-polar sapogenin side chain and a water-soluble one, which is close to the structure of most lipophilic and hydrophilic molecular sections of synthetic surfactants. The foaming power of the 0.6% crude saponins solution, 0.6% SLS solution and 0.6% Tween 80 solution were found to be 80%, 93.87% and 97.56% respectively. It showed that 0.6% crude saponins possessed moderate foaming ability. The surface active properties of saponin were also compared with the synthetic surfactants such as sodium lauryl sulfate (SLS) and Tween 80. Surface tension of 0.6% solution of saponin, SLS and Tween 80 was determined as 37.39 mN/m, 26.15 mN/m and 37.18 mN /m respectively. Critical micelle concentration (CMC) values of saponin and Tween 80 was comparable.

Partitioning of Selected Anisole and Veratrole Derivatives between Water and Anionic Surfactant Micelles.

The UV absorption spectra of six structurally related derivatives of anisole and veratrole, i.e., anisaldehyde, (E)-anethole, estragole, veratraldehyde, methyleugenol and (E)-methylisoeugenol, were recorded at various concentrations of the anionic surfactants, either sodium lauryl sulfate (SLS) or sodium lauryl ether sulfate (SLES) at T = 298 K. In addition, conductivity and density measurements were made for the SLS and SLES solutions to determine the volumetric properties of the studied surfactants. Next, using the W. Al-Soufi, L. Pińeiro and M. Novo model (APN model) including the pseudo-phase model for micellar solubilization, the values of micelle-water partition coefficients for each perfume-surfactant system were determined. In addition, the relations between the molecular structures of the solute and the head group of the surfactant and the value of the micelle-water partition coefficient as well as the octanol-water one were discussed.

The effect of microemulsion on coal wetting characteristics and physicochemical structure

To study the effect of microemulsion on the wettability and physicochemical structure of coal, various experiments (contact angle, Fourier infrared spectroscopy, scanning electron microscope) were conducted to study the mechanism of physicochemical structure on wettability. The results show that the microemulsion exhibited stronger wetting properties than traditional wetting agents such as water and sodium lauryl sulfate solution (SDS). The contact angles of the three-phase microemulsions were relatively small, among which the W/O type had better wettability. The increase in area percentage of benzene ring with one adjacent H, CH structure, OH…N structure had a tendency to inhibit coal wetting while the increase in area percentage of benzene ring with three adjacent H, CH3 structure, OH…π structure exhibited a tendency to promote coal wetting. Microemulsion could significantly increase the wettable area of coal. The research results have important practical significance for the configuration of mining wetting agents, reducing coal dust pollution, and diminishing coal mine disasters.

Effect of porous media and its distribution on methane hydrate formation in the presence of surfactant

Hydrates are mainly stored within sediment pores in nature. Therefore, understanding their formation characteristics within the porous space is essential to the transportation of natural gas based on the hydrate-based technology. In this paper, solutions of sodium lauryl sulfate (SDS), sodium dodecyl benzene sulfonate (SDBS), and alcohol ethoxylate (AEO) were used with different-sized porous media to investigate the characteristics (gas storage capacity, formation rate, and formation distribution) of the hydrate formation. The experimental results show that the gas storage capacity was higher in the complex system composed of a small-size porous media. The improvement of hydrate formation in the complex system composed of SDS or SDBS solution was more significant than that in the AEO system which could enhance the hydrate formation. In the three complex systems, the surface of alumina particles was positively charged by hydrolysis, which resulted in a double electron layer consisting of the counter ion in the adjacent liquid phase. The anionic active groups ionized by surfactants (i.e., SDS and SDBS) were aggregated to the surface of particles under Coulomb force. This increased the content of the methane molecules by non-polar adsorption and micellar solubilization. Finally, in the complex system of SDS solution and porous media, the capillary force caused by the pores of porous media could enhance the liquid phase migration in the pores which change the distribution of hydrate formation. This work presents useful insights on the hydrate formation characteristics which are beneficial to the rapid formation of hydrate and its industrial application of both storage and transportation of natural gas in complex porous systems.

Features of aqueous polymer-stabilized foams particularly containing bentonite particles

Using self-foaming dispenser, wet aqueous foams were prepared from isoviscous solutions of sodium lauryl sulfate (SLS) with chemically distinct polymer stabilizers. Contribution of coalescence and Ostwald ripening to the foam decay was examined from photos and video data. The bubble coarsening was estimated by dispersion analysis using the Lifshitz–Slezov–Wagner equation. Water-soluble polymers were selected from typical thickeners and suspending agents. Xanthan gum, hydroxyethyl cellulose, polyacrylamide, cross-linked sodium polyacrylate, cross-linked and hydrophobically modified (meth)acrylate copolymers were tried as foam stabilizers. By the same way, xanthan gum and submicron bentonite particles were used as foam stabilizers. Stability of the foams containing mentioned polymers as well as xanthan plus bentonite studied by the photographs and dispersion analysis. The polymers characterize by their efficacy to stabilize the wet foam. Possible reasons for poor stabilization of the foam containing cross-linked polyacrylates, both hydrophilic and hydrophobically modified, are given. The behavior of polymer-containing foams and joint stabilizing action of xanthan and bentonite are explained by variations in the structure of foam films.

Purification of Liquid Radioactive Waste from Surfactants and Organic Compounds

During the operation of a nuclear power plant, a significant amount of liquid radioactive waste (LRW) is formed and accumulated, its recycling has one of the first priorities. One of the sources of liquid radioactive waste is drain water, which consists of surface-active substances (SA) and organic compounds (OC) of various natures. With this waste composition, the operation of the evaporator is significantly complicated. Thus, recycling of LRW will be simplified after purification from SA and OC. The paper discusses the theoretical aspects of oxidative-cavitation and electrohydrodischarge water purification from organic matter. A schematic circuit of experimental stands of combined cleaning methods was developed and presented. Studies were performed on model solutions of sodium lauryl sulfate (LS) (NaC12H25SO4) and ethylenediaminetetraacetic acid (EDTA) (C10H16N2O8). LS is chosen because it is the most common SA, which is present in the composition of various detergent and decontamination mixtures. The use of EDTA is due to its application in technological processes at nuclear power plants and the presence of liquid radioactive waste in the composition. The destruction of the OS occurs as a result of ozone oxidation, which is constantly splashing through the solution, and amplifies under the action of electrical impulses or ultrasonic (US) cavitation. The work identifies the patterns of reducing concentrations of model solutions, depending on the method of processing, pH-environment and duration of the process. It was found that the destruction of SA and OC occurred better when ozone was combined with US cavitation or electrical discharge, at high pH. The highest performance purification of solutions is as follows: use of electro-discharge and ozone (рН = 6.2) leads to about 71 % collapses, (рН = 10) ~ 61 % OC collapses; use of US cavitation and ozone (рН = 10) ~ 83.3 % SA collapses.

Development of a Discriminative and Biorelevant Dissolution Test Method for Atorvastatin/Fenofibrate Combination with Appliance of Derivative Spectrophotometry.

Nowadays, the market is flooded with combinations of drugs in various dosage forms, but there is a lack of official methods to quantify them. A single dissolution test method for the analysis of combined dosage form is preferred for simplification of quality control testing. If the developed dissolution medium mimics the biorelevant and discriminating dissolution procedure for drug products with limited drug aqueous solubility it is a useful tool for qualitative forecasting of the in vivo behavior of formulations. Dissolution profiles were evaluated for atorvastatin and fenofibrate in capsules, using a paddle-type United States Pharmacopeia dissolution apparatus in 900 mL of medium at 50 rpm and 37±0.5°C. The best medium was 900 mL of 0.5% w/v sodium lauryl sulfate. The cumulative % dissolution was more than 85% within 45 min for marketed tablets. The proposed dissolution test conditions have discriminative power, dissimilarity factor (f1) values are low (12-16%), and similarity (f2) factor values are also low (45-48%). Hence the use of 0.5% w/v sodium lauryl sulfate solution is justified. The dissolution method was validated (% relative standard deviation <2). To quantify both drugs simultaneously, a second derivative spectrophotometric method was established (λmax 281 nm and 296 nm, respectively, for atorvastatin and fenofibrate) in acetate buffer, pH 2.8 solution.