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This study explores a sustainable approach for synthesizing silver nanocomposites (AgNCs) with enhanced antimicrobial and bioactivity using safe Lactobacillus strains and a whey-based medium (WBM). WBM effectively supported the growth of Lactobacillus delbrueckii and Lactobacillus acidophilus, triggering a stress response that led to AgNCs formation. The synthesized AgNCs were characterized using advanced spectroscopic and imaging techniques such as UV‒visible, Fourier transform infrared (FT-IR) spectroscopy, transmission electron (TEM), and scanning electron microscopy with energy dispersive X-ray analysis (SEM-Edx). Lb acidophilus-synthesized AgNCs in WBM (had DLS size average 817.2-974.3 ± PDI = 0.441 nm with an average of metal core size 13.32 ± 3.55 nm) exhibited significant antimicrobial activity against a broad spectrum of pathogens, including bacteria such as Escherichia coli (16.47 ± 2.19 nm), Bacillus cereus (15.31 ± 0.43 nm), Clostridium perfringens (25.95 ± 0.03 mm), Enterococcus faecalis (32.34 ± 0.07 mm), Listeria monocytogenes (23.33 ± 0.05 mm), methicillin-resistant Staphylococcus aureus (MRSA) (13.20 ± 1.76 mm), and filamentous fungi such as Aspergillus brasiliensis (33.46 ± 0.01 mm). In addition, Lb acidophilus-synthesized AgNCs in WBM exhibit remarkable free radical scavenging abilities, suggesting their potential as bioavailable antioxidants. These findings highlight the dual functionality of these biogenic AgNCs, making them promising candidates for applications in both medicine and nutrition.

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Two chromatographic methods were developed for the assay of the FDA approved lozenges containing dextromethorphan hydrobromide (DXT) and menthol (MNT). The first was a green HPTLC method which uses a mobile phase of methanol-ammonia (10:0.1, v/v). The densitometric measurements of the spots which were retained at 0.28±0.01 for DXT and 0.76±0.02 for MNT was done at 210nm. The other method was RP-HPLC method with stability indicating merits at which a mixture of 20mM phosphate buffer pH 3 and acetonitrile as mobile phase in isocratic mode was used. The cited drugs were resolved in RP-HPLC method using isocratic elution using 20mM phosphate buffer: acetonitrile (65:35 v/v) with retention times of 2.21 and 3.47min for MNT and DXT, respectively and quantified using 215nm. Both methods were entirely validated and both methods were successfully able to analyze both drugs in presence of lozenges inactive ingredients. HPLC method had the advantage of being stability indicating at which resolution of the drugs from their forced degradation products was successfully attained. For HPTLC method, both drugs showed reasonable RF values when compared to rapidly eluted MNT in RP-HPLC; also it was more environmentally friendly than RP-HPLC as it used solvents which are less toxic and greener.

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Simple and rapid spectrophotometric methods are described for determination of two mixtures of tamsulosin (TM), as minor component, with either solifenacin (SL) or tolterodine (TL). The proposed methods involve treatment of the absorbance ratio spectra or zero order spectra by derivative or discrete Fourier function. TM and TL mixture could not be resolved by manipulation of their zero order spectra due to the strong overlap between both spectra and only derivative or Fourier function coefficients of ratio spectra could resolve their spectra. TM and SL mixture was fully resolved by the manipulation of both ratio and zero order spectra. The values of the derivative or the Fourier function coefficients of ratio spectra and/or zero order spectra, at either peak or trough points, were correlated to the concentration of each drug in each mixture. Calibration graphs were linear in ranges 2.5-40 and 30-500µg.mL-1 using derivative ratio and Fourier function ratio, 5-40 and 80-600µg.mL-1 using direct derivative and 2.5-40 and 30-300µg.mL-1 using direct Fourier function for TM and SL, respectively. The plots of derivative ratio amplitude and the Fourier function ratio coefficient versus concentration were linear over ranges 2.5-20 and 25-250µg.mL-1 for TM and TL, respectively. Higher sensitivity as indicated by lower values of detection and quantitation limits were obtained using Fourier convoluted spectra (ratio or zero order) compared to derivative methods. All validation aspects per ICH guidelines are included. The proposed methods were also applied for the studied drugs assay in their tablets and capsules.

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A simple and sensitive spectrophotometric method has been developed for the determination of five cephalosporins namely cefpodoxime (CFPD), ceftizoxime (CTIZ), ceftazidime (CZD), ceftriaxone (CTRX), and cefixime (CXIM). This method is based on the formation of yellow to yellowish brown complex between palladium (II) chloride and the investigated cephalosporins in the presence of sodium lauryl sulphate (SLS) as surfactant. The reaction conditions were studied and optimized. The procedure was validated. For each drug, the composition of this complex as well as its stability constant were also investigated. The proposed method was used for the determination of the above-mentioned drugs in their commercial preparations. The results were compared statistically with either official or published methods and showed no significant difference between the two methods.

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H-point standard additions method (HPSAM), based on spectrophotometric and spectrofluorimetric measurements, was proposed for simultaneous determination of glafenine (G) and glafenic acid (GA). A study of the absorption spectra of G and GA in various pH media has been carried out. Reasonably resolved UV-absorption spectra were obtained with a solution adjusted at pH 4.5 with citric acid-phosphate buffer. Additionally, the fluorescence properties in aqueous micellar systems of anionic, cationic and non-ionic surfactants were investigated. Well resolved fluorescence spectra were established in aqueous Triton X-100 solution at pH 7.8 (citric acid-phosphate buffer). As a comparative method, UV-derivative spectrophotometry (based on zero-crossing technique) was suggested. First-derivative value at 352 nm ((1)D(352)) and second-derivative value at 366 nm ((2)D(366)) were selected for the quantification of G and GA, respectively. The relative standard deviations of the proposed methods approximate 2%. The proposed methods were evaluated through the analysis of commercial tablets. The results were accurate and precise.

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A simple, sensitive and selective spectrofluorimetric procedure was developed for the determination of amoxycillin, cefadroxil and cefoperazone. The method is based on the reaction between these drugs and ethyl acetoacetate, in acidic medium, to give yellow fluorescent products with excitation wavelengths ranging from 401 to 467 nm and emission wavelengths ranging from 465 to 503 nm. The reaction conditions were studied and optimized. The reaction obeyed Beer's law over the range of 10.0-20.0, 1.5-1.0 and 50.0-100.0 microg ml(-1) for amoxycillin, cefadroxil and cefoperazone, respectively. Interference's from other antibiotics, drugs and dosage forms additives, in capsules and vials dosage forms, were investigated. The proposed method was applied to the analysis of pharmaceutical formulations (capsules and vials) containing the above antibiotics, either alone or in combination with other antibiotics or drugs. The validity of the method was tested by the recovery studies of standard addition which were found to be satisfactory. The results of the proposed method demonstrated that the method is equally accurate, precise and reproducible as the official methods (USP XXIII) and those published for the non-official binary mixtures.

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A simple, rapid, stability-indicating first-derivative spectrophotometric assay procedure for the determination of the degradation products of acetazolamide is described. The dissolution and kinetics of drug degradation in aqueous buffered solutions were studied using the proposed method. Acetazolamide solution exhibited optimum stability at pH 4. The influences of temperature and sonic energy on the degradation of acetazolamide in 0.01 M NaOH solution were also studied. The results showed first-order reaction kinetics, with a degradation rate constant and degradation half-life of 3.51 x 10(-3) day-1 and 8.23 days, respectively.

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