Pharmaceutical Formulation Samples Research Articles

Disposable stochastic sensors for fast analysis of ibuprofen, ketoprofen, and flurbiprofen in their topical pharmaceutical formulations

Three disposable stochastic sensors based on maltodextrin (dextrose equivalent = 4–7) and nanostructures (copper monolayer, carbon monolayer and carbon-copper composite layer) deposited using cold plasma on copy paper were proposed for the fast analysis of ibuprofen, ketoprofen and flurbiprofen in pharmaceutical formulation samples. The widest linear concentration ranges recorded were: for ibuprofen 1 fmol/L – 1 mmol/L when the disposable stochastic sensor based on carbon monolayer was used, for ketoprofen 1 fmol/L – 1 mmol/L when the disposable stochastic sensors based on copper monolayer and carbon-copper composite layer were used, and for flurbiprofen 1 fmol/L – 10 mmol/L when the disposable stochastic sensor based on carbon-copper composite layer was used. The lowest limit of detection recorded for each non-steroidal anti-inflammatory drug was 1 fmol/L.

An unmodified boron-doped diamond electrode for electroanalytical investigation and sensitive voltammetric quantification of antiviral drug famciclovir in the pharmaceutical formulation and serum samples

The current study offers an electroanalytical investigation and a novel voltammetric approach for the quantitative analysis of famciclovir (FCV) utilizing an unmodified boron-doped diamond (BDD) electrode. An irreversible, well-defined, diffusion-controlled anodic peak was observed at approximately +1.27 V (vs. Ag/AgCl) in acetate buffer solution (ABS, 0.1 mol L−1, pH 4.7) when the agent was tested using cyclic voltammetry. The voltammetric signals of the oxidation peaks are pH dependent (ranging from 2.0 to 7.0). Using square-wave mode, a good linear response was obtained for FCV quantification in 0.1 mol L−1 ABS (pH 4.7) solution at +1.26 V (vs. Ag/AgCl). Wide dynamic range was found for 0.1 to 50.0 μg mL−1 (3.11 × 10−7-1.56 × 10−4 mol L−1), with a low detection limit of 0.029 μg mL−1 (9.02 × 10−8 mol L−1). Applicability of the proposed method for the determination of FCV was demonstrated in the pharmaceutical formulation and model serum samples.

Electroanalytical investigation and voltammetric quantification of antiviral drug favipiravir in the pharmaceutical formulation and urine sample using a glassy carbon electrode in anionic surfactant media.

This work describes the electrochemical investigation of a promising antiviral agent, favipiravir (FAV) utilizing a nonmodified glassy carbon (GC) electrode, along with a unique voltammetric approach that can determine FAV with a good degree of accuracy, speed, and cost-effectiveness. Using cyclic voltammetry, the compound demonstrated a single well-defined and an irreversible oxidation peak at approximately +1.12 V (vs. Ag/AgCl) in Britton-Robinson (BR) buffer at pH 10.0. The synergistic effect of anionic surfactant, sodium dodecyl sulfate (SDS) on the adsorption ability of GC electrode remarkably increased the sensitivity of the stripping voltammetric measurements of FAV. Employing square-wave adsorptive stripping voltammetry at +1.17 V (vs. Ag/AgCl) (after 60 s accumulation at open-circuit condition) in BR buffer (pH 10.0) containing 3 × 10-4 M SDS, the linear relationship is found for FAV quantification in the concentration from 1.0 to 100.0 μg mL-1 (6.4 × 10-6-6.4 × 10-4 M) with a detection limit of 0.26 μg mL-1 (1.7 × 10-6 M). The proposed approach was used successfully to determine FAV in pharmaceutical formulations and model human urine samples.

An intelligent approach based on hybrid of principal component analysis-fuzzy inference system-adaptive neuro-fuzzy inference system for the simultaneous spectrophotometric determination of sofosbuvir and velpatasvir as antiviral drugs in pharmaceutical formulation and urine sample

In this study, a simple, fast, accurate, and inexpensive chemometrics-assisted spectrophotometric method was developed for the simultaneous determination of sofosbuvir (SOF) and velpatasvir (VEL) as antiviral drugs. Fuzzy inference system (FIS) and adaptive neuro-fuzzy inference system (ANFIS) along with principal component analysis (PCA) were used for the analysis of SOF and VEL in binary mixtures, pharmaceutical formulation, and urine sample. Root mean square error (RMSE) of FIS model was 0.1518 and 0.075 for SOF and VEL, respectively. Also, the average testing error related to the ANFIS method was achieved 2.23 ​× ​10−5 and 5.58 ​× ​10−6 for SOF and VEL, respectively. The range of mean recovery percentage was between 99.76 and 100.41 for both methods. Relative standard deviation (RSD) of the real sample was lower than 0.06% for FIS and ANFIS for both components. Analysis of variance (ANOVA) was applied to the results of the real sample that there was no significant difference between the suggested approaches. PCA-FIS and PCA-ANFIS as efficient and accurate methods can be useful for the simultaneous estimation of binary and ternary mixtures in quality control of pharmaceutical formulations.

A Novel Carbon Nitride Nanosheets‐based Electrochemical Sensor for Determination of Hydroxychloroquine in Pharmaceutical Formulation and Synthetic Urine Samples

AbstractThis study introduces modified carbon paste electrodes with carbon nitride nanosheets (CNNS) and outlines their application for the determination of hydroxychloroquine sulfate (HCQ) in tablets and synthetic urine samples. CNNS were synthesized by hydrothermal route (200 °C, 10 h) using melamine and citric acid as their precursors. The carbon nitride nanosheets‐based electrode (CNNS/E) presented a linear dynamic range for HCQ (LDR), ranging from 10.0 nmol l−1 to 6.92 μmol l−1, and detection (LOD) and quantification limits (LOQ) of 0.16 nmol l−1 and 0.52 nmol l−1, respectively. LOD and LOQ were calculated by the equations: LOD=3(Sd/b), and LOQ=10(Sd/b). The modified sensor presented excellent relative standard deviations for parameters such as repeatability (2.39 % and 1.87 %) and reproducibility (3.22 % and 2.32 %) in HCQ oxidation peaks (1 and 2). The CNNS/E has not shown significant variations in its anodic signal intensity in the presence of some organic and inorganic substances. It is worth bearing in mind that CNNS/E can be easily manufactured and the sensor has the lowest HCQ detection limits reported so far. The proposed sensor was successfully applied for HCQ determination in tablets and synthetic urine, showing good recovery values and an error of 0.60 % about comparative method in tablet samples, assuring the quality of the method.

Cost-effective green chromatographic method for the simultaneous determination of four commonly used direct-acting antiviral drugs in plasma and various pharmaceutical formulations

This article presents the simultaneous determination of multiple recently approved direct-acting antiviral (DAA) regimens using a sensitive, robust method. Reversed-phase high-performance liquid chromatographic method (RP-HPLC) has been developed to represent a green alternative of other reported methods for the simultaneous determination of the most common four DAAs used for chronic hepatitis C treatment, including sofosbuvir (SF), ledipasvir (LD), daclatasvir (DC), velpatasvir (VP) and tenofovir (TO) as internal standard (IS) in bulk, pharmaceutical dosage form and plasma samples. This method was performed with an environment-friendly mobile phase with the least amount of energy consumption and waste generation. Chromatographic conditions have been optimized in order to obtain well-resolved symmetrical peaks within a reasonable elution time. Separation was achieved using Waters XBridge BEH C18 Column (4.6 × 150 mm) using isocratic elution mode at a flow rate 0.8 mL.min−1 with the mobile phase 0.1% (v/v) triethylamine acidified water with ortho-phosphoric acid (OPA) pH 2.53 and acetonitrile in the ratio (70:30 v/v). Sample extraction was done using diethyl ether for the analyte and IS extraction from the plasma samples. The suggested method was validated within the concentration range (0.4–20 μg.mL−1) for all the studied drugs according to the ICH guidelines. Calibration plots showed a linear relationship for SF, LD, DC and VP with correlation coefficients ≥ 0.9995 and acceptable recoveries. The method has been applied for the analysis of the studied drugs in plasma samples and pharmaceutical dosage forms without any matrix interference and with % RSD less than 2%, indicating the method to be precise. The suggested method was also assessed using the analytical Eco-scale tool and Green Analytical Procedure Index (GAPI) by comparing the method with other reported methods in terms of sample preparation, consuming hazardous reagents, instrument energy consumption and waste generation. Eco-scale and GAPI results proved the greenness of our proposed method. Moreover, the proposed method has the advantage of analyzing several pharmacologically related drugs in the same run simultaneously, which allows the analysis of alternative therapeutic formulations under the same running conditions. Thus, much effort and time is saved for developing a specific method for every pharmaceutical mixture. This promotes the proposed method to be used for both quality control analysis and any bioavailability study for the simultaneous determination of any of the four antiviral drugs in the pharmaceutical formulation or plasma samples without any harmful effect on the environment or human health.

Batch injection analysis with amperometric detection for fluoroquinolone determination in urine, pharmaceutical formulations, and milk samples using a reduced graphene oxide-modified glassy carbon electrode.

In this work, the batch injection analysis system with amperometric detection using reduced graphene oxide as a modifier of glassy carbon electrode (GCE) was investigated for the simple, fast, and sensitive monitoring of levofloxacin (LEVO) and ciprofloxacin (CIPRO) in samples of pharmaceutical formulations, synthetic urine, and milk (low- and high-fat content). LEVO and CIPRO were quantified in seven samples using amperometric measurements at +1.10V vs Ag/AgCl, KCl(sat). The developed methods showed excellent analytical performance with limits of detection of 0.30 and 0.16μmolL-1, linear range from 3.0 to 50μmolL-1 and 1.0 to 50μmolL-1, relative standard deviation below 9.7 and 3.1%, and recovery ranges ranging from 80 to 107% and from 78 to 109% for LEVO and CIPRO, respectively. In addition, the minimum sample preparation (simple dilution) combined with a high analytical frequency (130 to 180 analyses per hour) can be highlighted. Thus, the methods are promising for implementation in routine analysis and quality control to different samples.

Molecularly Imprinted Electrochemical Sensor-Based Fe2O3@MWCNTs for Ivabradine Drug Determination in Pharmaceutical Formulation, Serum, and Urine Samples.

Ivabradine hydrochloride (IVR) is a medically important drug because of its ability to lower the heart rate. Techniques reported for IVR determination were expensive, laborious, besides being of poor selectivity. In this study, iron oxide @ carbon nanotube (Fe2O3@MWCNTs) nanocomposite and molecularly imprinted polymer (MIP) were synthesized and used in the fabrication of carbon paste electrodes (CPEs) for the potentiometric detection of IVR in biological and pharmaceutical samples. CPEs of the best sensor were formulated from graphite (41 wt%) as a carbon source, MIP (3 wt.%) as an ionophore, Fe2O3@MWCNTs (5 wt%) as a modifier, and nitrophenyl octyl ether (NPOE, 51 wt.%) as a conductive oil so-called plasticizer. The best sensor exhibits a Nernstian slope (response) of 56 mV decade–1 within the IVR concentration range from 1.0 × 10–3 M to 9.8 × 10–8 M with high selectivity against interfering species (ascorbic, maltose, glucose, lactose, dopamine, glycine) over those reported earlier. The use of Fe2O3@MWCNTs together with MIP in the electrode formulation was found to improve the limit of detection (LOD) from 630 to 98 nM along with high reversibility, a short response time of 30 s, and a good lifetime of more than 2 weeks. The sandwich membrane (SMM) method was used to quantify the H-bonding complexing strength of the MIP binding sites for IVR with Log βILn = 11.33. The constructed sensors were successfully applied for the IVR determination in blood serum, urine, and commercial formulations (Savapran®) with high sensitivity.

A simple, sensitive and efficient electrochemical platform based on carbon paste electrode modified with Fe3O4@MIP and graphene oxide for folic acid determination in different matrices

A new biomimetic sensor selective to folic acid based on a carbon paste modified with graphene oxide and Fe3O4 nanoparticles coated with molecularly imprinted polymer in the core@shell format (Fe3O4@MIPs) was obtained using the polyol method. The sensing phase was synthesized in a simple way and characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and Brunauer-Emmett-Teller (BET) surface area. In the binding experiments the selective material showed a high adsorption capacity (Q) of 30.4 mg g−1 for MMIP, while the Q value for MNIP (magnetic non-imprinted polymer) was 15.3 mg g−1 both of them following the Langmuir model to the adsorption procedure. After their efficiency was proven, these materials were used as modifiers in the electrochemical sensor (Fe3O4@MIP-GO/CPE). Under optimized conditions using the square-wave adsorptive voltammetry, the proposed sensor exhibited excellent response with a concentration linear range between 2.5 and 48 μmol L−1 and limit of detection of 0.65 μmol L−1 (S/σ = 3). The advantages obtained with the proposed method were high robustness, selectivity, and low cost being these characteristics due to the MIP; highly sensibility due to the high superficial area being the contribution of the magnetite in the core of material; and experimentally versatile since was possible carry out numerous reproductible analysis only make the renovation of the paste electrode surface by simple polishing. The sensor was applied successfully in pharmaceutical formulation and river water samples with recoveries percentages near 100%.

A portable solid-state potentiometric sensor based on a polymeric ion-exchanger for the assay of a controversial food colorant (sunset yellow).

Food additives are chemicals added to enhance the appearance, taste, or lifetime of food products. Authorities continuously update the lists of the allowed additives and their daily intake limits. Thus, authorities and food suppliers strictly monitor additives in food products to guarantee their safety and compliance with national laws and safety criteria. The daily intake of the food colorant sunset yellow is banned in some countries and strictly controlled in others. Herein, a chemically modified solid-state potentiometric sensor was fabricated and used for the direct, fast, sensitive and selective assay of sunset yellow in soft drink and pharmaceutical formulation samples. The study optimized the sensor composition and the optimized carbon paste included a novel polymeric ion-exchanger, dioctyl phthalate, chitosan, and calix-[8]-arene and produced a rapid and near-Nernstian response of -32.9 ± 0.821 mV per decade for sunset yellow in the concentration range 7.94 × 10-5 M to 1.0 × 10-2 M and in the pH range 5-10. The sensor revealed good selectivity toward sunset yellow in the presence of commonly encountered ionic species. The method was validated according to the International Council for Harmonization guidelines and the results were statistically comparable to those of a reported method. The solid-state sensor represents a tool for fast and direct assay of sunset yellow in food products without sample pretreatment.

A novel nano-lanthanum complex: synthesis, characterization and application as a macrofuran chemosensor in pharmaceutical, biological and environmental samples.

Macrofuran is widely used as an antibiotic for the treatment of urinary tract infections. Nevertheless, it is prohibited due to toxicity and environmental concerns. The development of a fast, simple, and cost-effective approach for the determination of macrofuran antibiotic (MFA) is still a challenge. Herein, we report a chemosensor based on a nano-lanthanum complex derived from phenylenediamine. The physicochemical properties and structure of the prepared complex were confirmed using different spectroscopic tools such as X-ray diffraction (XRD), scanning electron microscopy equipped with EDX, elemental analysis, Fourier transform-infrared (FT-IR) spectroscopy, UV-vis spectroscopy, mass spectroscopy and photoluminescence (PL). The nano-lanthanum complex was found to be chemically stable, highly sensitive and selective to MFA, without interference from other common antibiotics. The limit of detection for MFA was 0.025 ng mL−1, over a linear concentration range of 0.02–30.0 ng mL−1, with a correlation coefficient of 0.994. The nano-lanthanum complex can be used successfully as a promising chemosensor for MFA determination in pharmaceutical formulation and different biological samples (whole blood–serum–plasma). In addition, this approach will protect human beings from the environmental hazards of antibiotics through the detection of the low limit of MFA. Meanwhile, the mechanism of interaction between the nano-lanthanum complex and MFA was studied and investigated.

A rapid, simple and ultrasensitive spectrofluorimetric method for the direct detection of metformin in real samples based on a nanoquenching approach.

Metformin (MET), as an oral antidiabetic and antihyperglycemic agent, is widely used to treat type II diabetes mellitus. Because of its increasing consumption, developing a fast, simple, and selective method to determine its concentration in biological samples (serum and urine) and pharmaceutical formulations (tablets) is of great interest. In this study, we used a FRET-based fluorescent nanosensor (Tb-phen-AgNPs system) for sensitive detection of MET in tablet and serum samples. This method is based on the enhancing effect of MET on the emission intensity of the Tb-phen complex, which is quenched by AgNPs via energy transfer process (turn off-on mode). A good linear relationship between the MET concentration and enhanced emission intensity of the Tb-phen-AgNPs system was observed in the range of (0.75-3.7) × 10-6 M under optimum conditions. Limit of detection and limit of quantitation were calculated to be 0.43 × 10-6 M and 1.31 × 10-6 M, respectively. This method was successfully used to determine MET concentrations in pharmaceutical dosage form and in spiked serum sample. The obtained recoveries from pharmaceutical formulation and serum sample were in the range 86.75-98.97% and 85.10-100.96%, respectively. Collectively, our results indicated that the method described here is simple, sensitive, cost effective, and free from interference. Therefore, it can be used as an effective and routine method for the direct and rapid determination of MET levels in biological samples such as serum.

Fabrication of silver-grafted silica nanohybrids via aminosilane-inspired surface functionalization for enhanced electrochemical performance towards gastric cancer biomarker

Enhancing catalytic property as well as realizing direct electron transfer between the nanomaterials and the electrode surface is key to fabricating the catalytic materials. In the present research, a facile method is reported to design silver-grafted silica nanohybrids (SiO2@Ag-NHs) via sonolysis of a solution comprising of silver nitrate (AgNO3) and aminosilane functionalized silica nanospheres (SiO2 NSs) in the presence of sodium borohydride (NaBH4). The formation of SiO2@Ag-NHs was characterized using UV–visible spectroscopy, XRD, HRTEM, XPS analysis and its electrochemical sensing behaviours were examined for Tryptophan (Trp); an important biomarker of gastric cancer. The modified sensor (SiO2@Ag-NHs/GCE) shows enhanced electrocatalytic performance for Trp with a considerable detection limit (LoD) of 0.127 µM (S/N = 3), quantification limit (LoQ) of 0.193 µM (S/N = 10), and a sensitivity as high as 1.77 µA µM−1 cm−2. Finally, the practicability of the proposed SiO2@Ag-NHs/GCE was evaluated for quantification of Trp in pharmaceutical formulation and human serum samples and exhibited satisfactory recovery results.

A Portable Reflective Absorbance Spectrophotometric Smartphone Device for the Rapid and Highly Accurate Determination of Amlodipine in Pharmaceutical Formulation and Human Urine Samples.

The simple reflective absorbance spectrophotometric smartphone device for point-of-monitoring amlodipine is presented here for the first time. The immediate analysis of amlodipine in the human urine of the patients who suffered severe side effects of this drug is very important for the diagnosis, treatment, and reduction of the death rate. This measurement technique is based on the charge-transfer complex between amlodipine and picric acid, which forms a yellow product. This product can absorb light intensity from an LED strip and measure through the Blue channel from the RGB mode with a smartphone application. The linear relationship for amlodipine monitoring was found in a wide range from 100.0 μg L-1 to 140.0 mg L-1 (R2 = 0.999), and the limit of detection was found to be 25.0 μg L-1. Our proposed method can be applied to different smartphone brands with consistent sensitivity of amlodipine detection. Additionally, the determination of amlodipine in pharmaceutical formulations and human urine samples was demonstrated by our proposed method. The recoveries were indicated in the range of 98.60 - 100.00%, which is at the acceptable level for pharmacy. This method offers an interweaving of basic technology and chemical analysis with being environmentally friendly due to reducing the complex instrument and the amount of organic waste compared to the chromatographic technique and efficient use for the detection of amlodipine. Hence, this method can be applied for prompt medical diagnoses and laboratories with limited budget resources.

Molecularly Imprinted Sol‐Gel Sensing Film‐Based Optical Sensor for Determination of Sulfasalazine Antibiotic

AbstractIn this study, a simplistic optical sensing approach for determination of sulfasalazine (SSZ) antibiotic has been developed by combining molecular imprinting and sol‐gel techniques (MIP‐SG). The sol‐gel solution containing sulfasalazine (target molecule) was deposited as a thin film on the pretreated microscope glass slides to fabricate imprinted optical sensors. The binding properties of the sensor toward sulfasalazine were evaluated by UV‐Vis spectroscopy method. The influence of some experimental parameters affecting on the manufacturing process as well as the response of MIP‐SG sensing film were studied. Under optimal conditions, the UV‐Vis signals of proposed sensor showed a linear relationship with the SSZ concentration in the range from 0.5 to 80.0 μg mL−1 (R2=0.994) and detection limit of 0.26 μg mL−1 with benefits of good reproducibility (RSD=4.12 %) and storage stability. This sensor was successfully used for determination of SSZ in well water, pharmaceutical formulation and human urine samples.

Application of MWCNT/Ag‐Pt Nanocomposite Modified GCE for the Detection of Nevirapine in Pharmaceutical Formulation and Biological Samples

AbstractA study of nanosensor comprising of a glassy carbon electrode modified with a composite of multiwall carbon nanotube (MWCNT) and bimetallic (Ag‐PtNPs) for the determination of Nevirapine. The GCE/MWCNT/Ag‐PtNPs sensor had remarkable electrocatalytic properties with enhanced response towards Nevirapine under optimized conditions. The platform electrochemical characterisation in 0.01 M NaOH solution, with cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) is detailed. The limit of the detection (LOD) was 0.021 μM. The nanosensor was validated for real sample study using spiked pharmaceutical dose form, milk and urine samples, which showed acceptable recoveries (90‐ 112 %), good precision (RSD=3.3 %, N=3), reproducibility (RSD=4.3 %) and excellent selectivity towards Nevirapine from studied interferents.

Disposable Pencil Graphite Electrode for Ciprofloxacin Determination in Pharmaceutical Formulations by Square Wave Voltammetry

AbstractIn this work, a new electrochemical sensor based on pencil graphite with interesting features, such as low cost (US$ 0.01 per electrode), ease manufacture, and portability was developed. The sensor showed an adequate manufacturing reproducibility with RSD <5.3 %. Under this electrochemical platform, ciprofloxacin underwent an irreversible oxidation process at 1.03 V, characterized by the diffusion of electroactive species. A simple method by square wave voltammetry (SWV) has been optimized for the determination of ciprofloxacin in pharmaceutical formulations using a pencil graphite electrode (PGE). The method showed satisfactory analytical performance, with a wide linear range (12 to 55 μmol L−1), low detection limit (5.6 μmol L−1), adequate precision (RSD <3.2 %), and accuracy with an average recovery of (102±15)%. Samples of pharmaceutical formulations were evaluated, obtaining levels of ciprofloxacin close to those established by the manufacturers. In addition, the samples were analyzed by liquid chromatography and there was no significant difference between the methods at the 95 % confidence level. In this sense, the method developed proved to be reliable and promising for the quality control of pharmaceutical formulations.

A Versatile and Ultrasensitive Electrochemical Sensing Platform for Detection of Chlorpromazine Based on Nitrogen-Doped Carbon Dots/Cuprous Oxide Composite.

The excessive intake of chlorpromazine (CPZ) adversely affects human health profoundly, leading to a series of severe diseases such as hepatomegaly and dyskinesia. The rapid and precise detection of CPZ in real samples is of great significance for its effective surveillance. Herein, a versatile and sensitive electrochemical sensor was developed for the detection of antipsychotic drug CPZ based on a Nafion (Nf)-supported nitrogen-doped carbon dots/cuprous oxide (N-CDs/Cu2O) composite. The as-synthesized N-CDs/Cu2O composite was systematically characterized using various physicochemical techniques. The developed composite-based sensor displayed excellent performance towards CPZ determination in a dynamic linear range of 0.001–230 µM with the detection limit of 25 nM. Remarkably, the developed sensor displayed good performance in terms of sensitivity and selectivity. Furthermore, good anti-interference properties toward CPZ determination were attained despite the presence of highly concentrated interfering compounds. Therefore, this composite could be a notable potential modifier to enhance electrocatalytic activity onto the surface of the electrode. Finally, N-CDs/Cu2O/Nf-based sensor was effectively applied for quantification of CPZ in human urine and pharmaceutical formulation samples.

A Green RP-HPTLC-Densitometry Method for the Determination of Diosmin in Pharmaceutical Formulations

Green analytical technologies for the determination of a bioactive compound diosmin (DIOM) in the real samples of pharmaceutical formulations and biological fluids are scarce in literature. Therefore, the present investigation was carried out to develop a novel, rapid, simple, and economical green “reversed phase high-performance thin-layer chromatography (RP-HPTLC)” method for the determination of DIOM in commercial tablets and in-house developed spray-dried microparticles (MPs). The quantification of DIOM was conducted via “RP-18 silica gel 60 F254S HPTLC plates”. The binary combination of green solvents, i.e., ethanol:water (5.5:4.5 v/v) was proposed as a green mobile phase. The analysis of DIOM was conducted in absorbance/reflectance mode of densitometry at λmax = 348 nm. The densitograms of DIOM from the commercial tablets and in-house developed spray-dried MPs were verified by recording their single band at Rf = 0.80 ± 0.02 compared to standard DIOM. Green RP-HPTLC method was observed as linear in the range of 100–700 ng/band with R2 = 0.9995. The proposed method was found as “accurate, precise, robust, and sensitive” for the determination of DIOM in the real samples of commercial tablets and in-house developed spray-dried MPs. The % content of DIOM in the real samples of commercial tablets and in-house developed spray-dried MPs was obtained as 99.06 and 101.30%, respectively. The recorded results of this research suggested that the green RP-HPTLC method can be effectively used for the routine analysis of DIOM in pharmaceutical products.

Application of Rank Annihilation Factor Analysis for Antibacterial Drugs Determination by Means of pH Gradual Change-UV Spectral Data.

The main objective of this study was to develop a simple and efficient spectrophotometric technique combined with chemometrics for the simultaneous determination of sulfamethoxazole (SMX) and trimethoprim (TMP) in drug formulations. Specifically, we sought: (i) to evaluate the potential use of rank annihilation factor analysis (RAFA) to pH gradual change spectrophotometric data in order to provide sufficient accuracy and model robustness; and (ii) to determine SMX and TMP concentration in drug formulations without tedious pre-treatments such as derivatization or extraction techniques which are time-consuming and require hazardous solvents. In the proposed method, the spectra of the sample solutions at different pH values were recorded and the pH-spectra bilinear data matrix was generated. On these data, RAFA was then applied to estimate the concentrations of SMX and TMP in synthetic and real samples. Applying RAFA showed that the two drugs could be determined simultaneously with concentration ratios of SMX to TMP varying from 1:30 to 30:1 in the mixed samples (concentration range is 1–30 µg mL−1 for both components). The limits of detection were 0.25 and 0.38 µg mL−1 for SMX and TMP, respectively. The proposed method was successfully applied to the simultaneous determination of SMX and TMP in some synthetic, pharmaceutical formulation and biological fluid samples. In addition, the means of the estimated RSD (%) were 1.71 and 2.18 for SMX and TMP, respectively, in synthetic mixtures. The accuracy of the proposed method was confirmed by spiked recovery test on biological samples with satisfactory results (90.50–109.80%).