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In the present work, the determination of omeprazole (OME) enantiomers in oral fluid and plasma samples was carried out utilizing microextraction by packed sorbent (MEPS) and liquid chromatography-tandem mass spectrometry. A chiral column with cellulose-SB phase was used for the first time for enantiomeric separation of OME with an isocratic elution system using 0.2% ammonium hydroxide in hexane-ethanol mixture (70 : 30, v/v) as the mobile phase. OME enantiomers were determined utilizing a triple quadrupole tandem mass spectrometer in positive ion mode (ESI+) monitoring mass transitions: m/z 346.3 ⟶ 198.0 for OME and m/z 369.98 ⟶ 252.0 for internal standard. The limits of detection and quantification of the present method for both enantiomers were 0.1 and 0.4 ng/mL, respectively. The method validation provided good accuracy and precision. The matrix effect factor was less than 5%, and no interfering peaks were observed. The interday precision values ranged from 2.2 to 7.5 (%RSD), and the accuracy of determinations varied from −9.9% to 8.3%. In addition, the pharmacokinetics (PK) of omeprazole enantiomers in healthy subjects after a single oral dose was investigated. (S)-Enantiomers showed higher levels than (R)-enantiomers throughout 24 h. It was found that the mean maximum concentrations of (R)- and (S)-omeprazole in plasma samples were about two times higher than in oral fluid.

To date, there is no an established protocol for total RNA isolation in Egyptian buffalo spermatozoa. The present study aimed (I) to establish a defined protocol for total RNA isolation from fresh and frozen spermatozoa, (II) to evaluate RNA quality and quantity from different extraction methods and studying gene expression. Warm and standard room temperature modified QIAzol Lysis Reagents were used for total RNA extraction. The quality and quantity of extracted RNA were checked, and subsequently qRT-PCR was performed using androgen receptor-like and three reference gene primers (GAPDH, ACTB and 18S). The warm modified QIAzol Lysis Reagents resulted higher yield of good quality RNA from fresh (569.54 ± 18.83 ng/μl) and frozen spermatozoa (110.59 ± 4.43 ng/μl), compared to standard room temperature modified QIAzol (421.26 ± 7.18 ng/μl) and (29.07 ± 5.25 ng/μl), for fresh and frozen semen samples respectively. The 260/280 ratio was 1.90 and 1.89 for fresh and frozen isolated semen by warm method respectively. The integrity of RNA was good and appeared as a sharp band on 2% agarose gel. The most stable reference gene was 18S. Reliable extraction method of high quality RNA yield could be a step forward for understanding mechanisms of spermatogenesis for improving male fertility.

A sensitive, accurate and reliable bioanalytical method for the enantioselective determination of metoprolol in plasma and saliva samples utilizing liquid chromatography-electrospray ionization tan ...

An Online post-column solvent-assisted ionization (OPSAI) method was developed for enhancing the ionization of the beta-blocker propranolol utilizing normal phase LC-MS/MS. Solvent-assisted electrospray ionization (SAESI) was studied by the introduction of the assistant solvents A: 0.5% Formic acid in Isopropanolol, B: 0.5% Formic acid in Isopropanolol-Water (1:1), and C: 0.5% Formic acid in water into the electrospray ionization chamber using a spray needle. Analyte molecules can be directly ionized by the aid of the assistant solvent spray. Both methods were applied to the chiral separation of propranolol enantiomers using normal phase analysis on cellulose-based chiral column. Interestingly, both methods are easy to handle and offer a wide range of assistant solvents that can be used in order to gain the optimum ionization of the analyte molecules. The both methods considerably improved the analyte signal and the peak area greatly increased. The propranolol average signal-to-noise (S/N) ratio was enhanced from 26±1 and 42±1 to 2341±61 and 1725±29 for R-propranolol and S-propranolol, respectively, when the post-column solvent method (OPSAI) was used with isopropanol-assistant solvent (A). While in case of solvent-assisted electrospray ionization method (SAESI) signal was enhanced from 26±1 and 42±1 to 2223±72 and 2155±58 for R-propranolol and S-propranolol, respectively, with water as an assistant solvent. The limit of detection was 10ng/mL and the method was linear in the range 50-2000ng/mL. The NPLC-MS method was applied for the determination of propranolol enantiomers in human plasma after microextraction by packed C18 sorbent.

The aim of this study is to evaluate the reno-protective effect of the defatted methanolic extract of Stevia rebaudiana which showed the highest improvement of renal parameters, as it reduced the protein urea, blood urea nitrogen and blood creatinine and nephroprotective properties with reduced hyperglycemia complications through protection of renal tissues in type-1 diabetes. Also, identification of bioactive phenolic compounds of defatted methanolic extract using HPLC analysis, demonstrate the presence of diterpene glycosides, stevioside, rebaudioside A and chlorogenic acid

An enantioselective high performance liquid chromatographic method with diode array detection (HPLC-DAD) was developed and validated for the determination of etodolac enantiomers in tablets and human plasma. Enantiomeric separation was achieved on a Kromasil Cellucoat chiral column (250 mm × 4.6mm i.d., 5 µm particle size) using a mobile phase consisting of hexane: isopropanol: triflouroacetic acid (90:10:0.1 v/v/v) at a flow rate of 1.0 mL min(-1). The chromatographic system enables the separation of the two enantiomers and the internal standard within a cycle time of 8 min. The resolution between the two enantiomers was 4.25 and the resolution between each enantiomer and the internal standard was more than 2.0. Detection was carried out at 274 nm, and the purity assessment was performed using a photodiode array detector. Solid phase extraction technique using C-18 cartridge was applied to extract the analytes from the plasma samples, and the percentage recovery was more than 95% for the lower quantification limit. The method has been validated with respect to selectivity, linearity, accuracy and precision, robustness, limit of detection and limit of quantification. The validation acceptance criteria were met in all cases. The linearity range for the determination of each enantiomer in human plasma was 0.4-30.0 µg mL(-1) and the limits of quantification of R-etodolac and S-etodolac were 0.20 and 0.19 µg mL(-1), respectively. The validated method was successfully applied to the determination of etodolac enantiomers in tablets and to a comparative pharmacokinetic study of the two enantiomers after the administration of 300 mg single oral dose etodolac racemate tablets to twelve healthy volunteers.

Background High-throughput technologies have the potential to identify non-invasive biomarkers of liver pathology and improve our understanding of basic mechanisms of liver injury and repair. A metabolite profiling approach was employed to determine associations between alterations in serum metabolites and liver histology in patients with chronic hepatitis C virus (HCV) infection. Methods Sera from 45 non-diabetic patients with chronic HCV were quantitatively analyzed using 1H-NMR spectroscopy. A metabolite profile of advanced fibrosis (METAVIR F3-4) was established using orthogonal partial least squares discriminant analysis modeling and validated using seven-fold cross-validation and permutation testing. Bioprofiles of moderate to severe steatosis (≥33 %) and necroinflammation (METAVIR A2-3) were also derived. The classification accuracy of these profiles was determined using areas under the receiver operator curves (AUROCSs) measuring against liver biopsy as the gold standard. Results In total 63 spectral features were profiled, of which a highly significant subset of 21 metabolites were associated with advanced fibrosis (variable importance score >1 in multivariate modeling; R2 = 0.673 and Q2 = 0.285). For the identification of F3–4 fibrosis, the metabolite bioprofile had an AUROC of 0.86 (95 % CI 0.74–0.97). The AUROCs for the bioprofiles for moderate to severe steatosis were 0.87 (95 % CI 0.76–0.97) and for grade A2–3 inflammation were 0.73 (0.57–0.89). Conclusion This proof-of-principle study demonstrates the utility of a metabolomics profiling approach to non-invasively identify biomarkers of liver fibrosis, steatosis and inflammation in patients with chronic HCV. Future cohorts are necessary to validate these findings. Electronic supplementary material The online version of this article (doi:10.1186/s40169-016-0109-2) contains supplementary material, which is available to authorized users.

Objective: The present study examined the effects of aqueous and methanolic extracts of palm dates (fruits and seeds) on diabetic nephropathy in a rat model of type 2 DM. Methods: Sixty male albino rats subdivided into a) normal control (NC) group, b) diabetic control (DM) group, c) aqueous fruit extract (AFE) group, d) methanolic fruit extract (MFE) group, e) aqueous seed extract (ASE) group and f) methanolic seed extract (ASE) group. Treatment with both extracts done for 15 weeks after induction of type 2 DM. by the end of experiment fasting blood glucose, serum lipid profile, creatinine, urea, uric acid, urinary albumin excretion, kidney tissue MDA, catalase, SOD, GSH were measured and kidney histopathological examination was done. Results: Diabetic untreated rats showed significant hyperglycemia and hyperlipidemia and deterioration in kidney functions and morphology with enhanced oxidative stress in kidney tissues. On other hand, rats treated with either aqueous or methanolic fruit or seed extracts showed significant improvement in all studied parameters compared to DM group (p

This study involves the development and characterization of a series of sodium alginate-based pH-responsive hydrogel microspheres encapsulating poly( d , l -lactic-co-glycolic acid) (PLGA) nanoparticles (NPs). The effect of the drying technique (air- or freeze-drying) on the size of the developed particles was determined. Swelling characteristics at different pH values, in vitro biodegradation and moisture contents of both air-dried and freeze-dried hydrogel particles were investigated. The effect of drying method on the morphology of the particles was also studied using SEM and AFM. Then, the developed alginate-PLGA particles were evaluated as potential carriers, through a new approach, to improve the dissolution, bioavailability and oral sustained release of silymarin, as a model of hydrophobic natural therapeutics. The used silymarin was isolated from the seeds of some native milk thistle (Silybum marianum) ecotypes of delta Egypt and was characterized with the aid of several analytical techniques including; 1H NMR, UV and FTIR. The obtained data showed a considerable effect of the alginate content and the drying method onto the characteristics of the prepared particles. Also, the results demonstrated that the developed alginate-based hydrogel microparticles encapsulating silymarin-loaded PLGA NPs can be used as biodegradable carriers that can confer sustained oral release of silymarin in addition to enhancing its overall dissolution and oral bioavailability.

The two stereo-isomers; quinine and quinidine have been determined in their mixtures in the IR region using chemometric multivariate methods, principal component regression (PCR) and partial least squares (PLS). A training set of thirty synthetic binary mixture solutions in the possible combinations containing 0.0 - 4.0 and 4.0 - 0.0% w/v quinine and quinidine, respectively in chloroform was used to develop the multivariate calibrations. A validation set containing thirty synthetic binary mixtures of variable ratios in the range of 0.2 - 4.0 and 4.0 - 0.2% w/v for quinine and quinidine, respectively in chloroform was used to validate the developed calibrations. The results of analysis of the validation synthetic mixtures were found to be 100.5+/-0.44% (R.S.D.%=0.44) and 100.5+/-0.38% (R.S.D.%=0.38) for quinine and 100.1+/-0.67% (R.S.D.%=0.67) and 100.1+/-0.68% (R.S.D.%=0.68) for quinidine using PCR and PLS models, respectively.

This work is a part of long program for producing natural polymers which is used for application in different purposes in agriculture fields. A part of this program was the preparation of various compositions of Gum Arabic (GA) and Poly vinyl alcohol (PVA) with studying its physical and chemical characters. Whereas, the present work was concerning with the evaluation of released amount of selected micronutrients from the same complex under laboratory and field conditions. In the laboratory, the prepared complex containing copper (Cu) or manganese (Mn) separately, were tested at different pH values for releasing at intervals. The obtained results showed the possibility of using the Mn+2 complex at 3000 mg kg−1. Moreover, the obtained results showed that the maximum released amount was obtained at pH 7.0. A field experiment was planed according to the resulted data obtained in laboratory. Samples were taken for elemental analysis either from soil or plants during all growth stages likeas vegetative, floweri...

Highly sensitive, simple and accurate reversed phase liquid chromatographic and first derivative spectrophotometric methods for determination of antihistaminic drug loratadine [I] and nasal decongestant drug pseudoephedrine sulfate [II] are described. The HPLC method involves separation of [I] and [II] on micro-BondaPak C18 column using mixture of (methanol:H(2)O:phosphoric acid:ammonium dihydrogen phosphate) (220:300:2:3 g) (V/V/V/W), 60 and 40% acetonitrile as mobile phase flowing at 2 ml/min with ultraviolet detection at 247 nm. The calibration graphs are linear from 5 to 100 microg/ml for [I] and from 120 to 1200 microg/ml for [II] the detection limits are 0.5 microg/ml for [I] and 60 microg/ml for [II]. The spectrophotometric method is based on recording the first derivative spectra for [I] and [II] at 307, 266 nm, respectively, of their solutions in 0.1 M hydrochloric acid using the acid as blank. The calibration graphs are linear in the range of 5-25 microg/ml for [I] and 240-720 microg/ml for [II]; the limits of detection are 0.16 microg/ml for [I] and 10 microg/ml for [II]. The mean percentage recoveries obtained for different synthetic mixtures by using this method are 97.6% with coefficient of variation 1.79 for [I] and 101.6% with coefficient of variation 1.95 for [II]. The two methods have been applied successfully for the determination of [I] in its combination with [II] Clarinase tablets and [I] alone in different pharmaceutical dosage forms.

The compensation method and other chemometric methods (derivative, orthogonal function and difference spectrophotometry) have been applied to the direct determination of omeprazole, lansoprazole and pantoprazole in their pharmaceutical preparations. The methods have been validated; the limits of detection were found to be 3.3x10(-2), 3.0x10(-2) and 3.5x10(-2) microgram ml(-1) for the three drugs, respectively. The repeatabililty of the methods were found to be 0.3-0.5%. The linearity ranges were found to be 0.5-3.5 microgram ml(-1). The proposed methods have been applied to the determination of the three drugs in their grastro-resistant formulations. The difference spectrophotometric (DeltaA) method is unaffected by the presence of acid induced degradation products; hence can be used as a stability indicating assay.

A differential pulse polarographic method is described for detection and trace determination of benzophenone (the main impurity) in phenytoin powder. The method depends upon the polarographic activity of benzophenone in Britton-Robinson buffer pH 5.6. The limit of detection was found to be 2.5 x 10(-6) microg ml(-1). Phenytoin has been analysed polarographically after oxidation with alkaline permanganate to give benzophenone; the limit of detection was found to be 6 x 10(-6) microg ml(-1).

An accurate technique has been developed to calculate the equivalent width of absorption lines. The calculations have been carried out for the pure Doppler and pure Lorentz limiting forms of the equivalent width. A novel expression for the equivalent width for Lorentz profile is given from direct integration of the line profile. The more general case of a Voigt profile leads to an analytical formula that permits a rapid estimate of the equivalent width for a wide range of maximum optical depths. The reliability of the approach is verified using a numerical application calculating the equivalent width for nickel resonance lines at 232.0 and 352.3 nm from atomic absorption (AA) measurements. The dependence of equivalent width on the number density of absorbing atoms is also provided. The results obtained for the equivalent width for the Voigt profile were compared with the data in the available literature obtained by different approaches.

Streaming potential measurements detected the presence of adsorbed polyvinylamine or potassium polyvinylsulfate in paper-based microfluidic devices. Capillary driven flow in filter paper induced measurable potentials in the range −80 to +80 mV. The magnitude and polarity of the measured potentials were sensitive to the presence of adsorbed polymer. In a second example, paper treated with BSA gave a positive streaming potential at pH 3.7, below the isoelectric point of BSA, and a negative potential at high pH. We propose that streaming potential may provide an electronic interface for paper-based biosensors.

The application of two-component analysis methods, differentiation of signals and orthogonal function, to the resolution of partially overlapping differential pulse voltammetric (DPV) peaks is demonstrated. The study was extended to differential pulse cathodic stripping voltammetry (DPCSV). A binary system of tin(II) and lead(II), having 72 mV of DPV peaks separation in 0.04 M acetic/ o -phosphoric/boric acids’ mixture, was used as a model throughout the work. The stripping voltammetric analysis data processed by orthogonal functions and the first-derivative ( 1 D) methods, were successfully applied to the simultaneous determination of both metals in canned soft drinks. Moreover, the applicability of the methods were demonstrated by the recovery of lead in a drinking water sample.

A simple and sensitive spectrophotometric method is described for the determination of buclizine hydrochloride in bulk and tablets form. The method is based on the formation of charge-transfer complex between buclizine, as n-donor, and iodine, as Δ acceptor, which measured spectrophotometrically at 295 and 355 nm. A Job's plot indicated a 1:1 complex between the drug and iodine and Beer's law was obeyed in a concentration range of 4–30 μg ml−1. A more detailed investigation of the complex was made with respect to its association constant and the free energy change. The method is simple and sensitive and has been applied successfully to the analysis of laboratory-made tablets without any interference from the tablet excipients. To validate the method, the results obtained were compared statistically with a newly developed uv-derivative spectrophotometric method. The charge-transfer method was favored due to its higher sensitivity, cheap coast and available equipments.

A simple, stability-indicating liquid chromatographic method has been developed for the assay of flunarizine dihydrochloride in the presence of its acid-induced degradation product. A Bondapak-C18 column was used with a mobile phase consisting of methanol-water (75:25, v/v) containing 0.5% w/v sodium chloride and 0.2% v/v triethanolamine adjusted to pH 6.6 with 30% hydrochloric acid at a flow rate 2 ml min−1. Quantitation was achieved with UV detection at 254 nm based on peak area or peak height ratios. The proposed method was successfully applied to the determination of the drug in laboratory-prepared mixtures in the presence of its degradation product and in capsules. Moreover, the method was utilized to investigate the kinetics of the degradation process at different temperatures and the apparent first-order rate constant, half-life and activation energy calculated.

A spectrophotometric method is described for the assay of flunarizine dihydrochloride. The method is based on the molecular interaction between the drug and iodine, to form a charge-transfer complex in which the drug acts as n-donor and iodine as sigma-acceptor. The iodine was found to form charge-transfer complex in a 1:1 stoichiometry with absorption bands at 295 and 355 nm. The concentrations were linear over 8-13 micrograms ml-1 at both 295 and 355 nm, respectively. A complete, detailed investigation of the formed complex was made with respect to its composition, associated constant and free energy change. The method has been applied successfully to the analysis of commercially available flunarizine dihydrochloride capsules without interference from the capsules excipient. To validate the proposed method, its accuracy and precision, the results were statistically compared with a newly developed reversed-phase HPLC procedure using Student-t and F-ratio tests.

Two easy to handle, sensitive and specific fluorimetric methods for the detection and determination of morphine in codeine are described. In method A the codeine sample investigated is treated with alkaline potassium ferricyanide, whereby morphine when present will produce the fluorescent dimer pseudomorphine. In method B, the codeine sample is thermally treated with gaseous ammonia on a chromatographic plate where morphine, if present, is converted to a highly fluorescent derivative. The limits of detection were 10 ng and 20 ng for methods A and B respectively.

Glenn's method of orthogonal functions (J. Pharm. Pharmacol., 15 (1963) 123T–130T) is extended to the spectrophotometric determination of dissociation constants of some weakly acidic and basic drugs. The calculated comparative coefficients, Qj, of the dissociated, undissociated and partially dissociated forms of the drug have been used to calculate the pKa values. A graphical technique based upon plotting orthogonal function titration curves is also presented. The results obtained are in good agreement with the reported values.

A sensitive and rapid Spectrofluorimetric method for the determination of guanethidine sulphate, guanfacine hydrochloride, guanoclor sulphate and guanoxan sulphate in tablets and spiked human serum and urine samples is described. The method is based on the reaction of monosubstituted guanidino compounds in an aqueous potassium hydroxide solution with benzoin, in the presence of β-mercaptoethanol and sodium sulphite. Highly fluorescent derivatives were obtained, with excitation and emission maximum wavelengths around 325 and 430 nm, respectively. In optimal reaction conditions, the linearity ranges were 0.04–0.28 μg/ml, with relative standard deviations less than 2%. The method has been successfully applied to the determination of these drugs in tablets. The results are highly correlated with the B.P. method. Chloroform (or for guanoxan dichloromethane) was used to extract the drugs from serum and urine at basic pH, followed by the proposed fluorimetric method. The limit of detection is 0.02 μg/ml for the selected drugs.

The Model for End-Stage Liver Disease (MELD) allocation system for liver transplantation (LT) may present a disadvantage for women by including serum creatinine, which is typically lower in females. Our objectives were to investigate gender disparities in outcomes among LT candidates and to assess a revised MELD, including estimated glomerular filtration rate (eGFR), for predicting waiting list mortality.Adults registered for LT between 2002 and 2007 were identified using the UNOS database. We compared components of MELD, MDRD-derived eGFR, and the 3-month probability of LT and death between genders. Discrimination of MELD, MELDNa, and revised models including eGFR for mortality were compared using c-statistics.A total of 40,393 patients (36% female) met the inclusion criteria; 9% died and 24% underwent LT within 3 months of listing. Compared with men, women had lower median serum creatinine (0.9 vs. 1.0 mg/dl), eGFR (72 vs. 83 ml/min/1.73 m(2)), and mean MELD (16.5 vs. 17.2; all p0.0005), but within most MELD strata, had higher bilirubin and INR. After adjusting for relevant covariates including creatinine and body weight, women were less likely than men to receive a LT (hazard ratio [HR] 0.85; 95% CI 0.79-0.87) and had greater 3-month mortality (HR 1.13; 95% CI 1.05-1.21). Revision of MELD and MELDNa to include eGFR did not improve discrimination for 3-month mortality (c-statistics: MELD 0.896, MELD-eGFR 0.894, MELDNa 0.911, MELDNa-eGFR 0.905).Women are disadvantaged under MELD potentially due to its inclusion of creatinine. However, since including eGFR in MELD does not improve mortality prediction, alternative refinements are necessary.

Second derivative spectrophotometry has been used to determine canrenone (I), the main degredation product in spironolactone (II). Second derivative at 300 nm was found linearly related to concentration in the range of 0.2–1 mg% I has been determined in II down to concentration level of 0.2 mg%. The results were found reproducible with a relative standard deviation of 1.7%.

Blood superoxide dismutase (SOD) and plasma malondialdehyde (MDA) (an indicator of lipid peroxidation [LPO]) were determined in 97 randomly selected asbestos exposed workers (age range: 25-60 years, mean duration of exposures 19.8 +/- 8.3 years) and in 42 healthy male controls. MDA, SOD, and MDA/SOD ratio in asbestos exposed workers were significantly higher than in controls. Among both the controls and exposed workers neither age nor smoking was related to SOD or MDA levels. SOD was significantly positively correlated with MDA among the exposed workers. Such correlation was not observed among the controls. SOD but not MDA was significantly positively correlated with the duration of exposure to asbestos. Mean levels of SOD or MDA in exposed workers with radiographic signs of lung fibrosis or pleural thickening did not differ significantly from those without such signs. The results confirm the possible involvement of LPO and development of anti-oxidant mechanism(s) of prolonged exposure to asbestos in humans. However, SOD seems not to be the essential anti-asbestos-induced LPO. Relation between these factors and lung fibrosis is still unclear.

The dye-salt formation method was successfully applied to the determination of chlorpheniramine maleate and chlorphenoxamine hydrochloride each in presence of caffeine. At pH 5, the chromogens (λmax=420 nm) produced with methyl orange in chloroform obeyed Beer's law over the range 5-15 ug/ml and with relative SD less than 1%.

An isocratic, sensitive high-per-Formance liquid chromatographic method has been developed for the determination of phenobarbitone, methylphenobarbitone and phenytoin in tablets. A reversed-phase octadecylsilane column, 10 µ, was utilized with a mobile phase consisting of 45% methanol, 55% water and 0.5 ml glacial acetic acid at a flow rate of 1.8 ml/min. The samples were dissolved in methanol containing diethylbarbituric acid as an internal standard. Quantitation was achieved with UV detection at 240 nm and by the measurment of the peak area ratio.

New chamigrenes, hurgadol and β-snyderyl acetate, and a new C 15 -cyclic ether-enyne, hurgadenyne, have been isolated from Laurencia obtusa . They were identified by spectroscopic methods. A crystal structure was obtained for hurgadol.

Derivative spectrophotometry is applied to the determination of the dissociation constants (pKa) of some weakly dissociating compounds. The pKa value(s) can be calculated by measuring the amplitude of derivative maxima (D) at the selected wavelengths for the dissociated, undissociated and partially dissociated forms of the compound. A graphical technique, based on plotting the derivative spectrophotometric titration curves and interpolating pKa at D1/2 is also presented. Both methods are applied to pharmaceutical compounds with single and double dissociation constants. The results are in good agreement with the reported pKa values of the investigated compounds.

A highly sensitive spectrofluorimetric method for the determination of some drugs of the monosubstituted guanidine derivatives in laboratory made tablets, in spiked human serum and in urine samples is presented. The method is based on the reaction of guanethidine sulphate (I), guanoxan sulphate (II) and amiloride hydrochloride (III) with 9,10-phenanthraquinone (IV) to give highly fluorescent derivatives. The linearity ranges were found to be 0.06-0.96 mug/ml for (I) and (II) and 0.04-0.28 mug/ml for (III), with relative standard deviation less than 2%. Mean percentage recoveries for tablets were found to be 99.9 +/- 1.3, 100.5 +/- 1.1 and 100.0 +/- 1.6 for I, II and III, respectively. For I and III the results are highly correlated with the B.P. methods. Using the synchronous fluorimetry, differentiation between I and II was possible. Chloroform, dichloromethane and ethyl acetate have been used to extract I, II and III, respectively from serum and urine at basic pH, followed by applying the proposed fluorimetric method. Percentage recoveries were found to be 95.7-102.2%. The limit of detection is 0.04 mug/ml for I and II and 0.02 mug/ml for III.

Summary A rapid, simple spectrophotometric method for the detection and determination of benzene in ethanol is described. Thus, using 1 cm cuvettes and applying the first and/or the second derivative methods, benzene can be determined in ethanol over the concentration range of 5–25 p.p.m. with a CV% less than 1 % and with a detection limit of 2 p.p.m. This is considered to be an improvement over the method currently given in the British Pharmacopoeia.

The components of electrocardiograms (ECG) of 253 workers exposed to carbon disulfide (CDS) and those of 99 controls were quantitatively measured and evaluated. ECG of the exposed workers showed a statistically significant higher prevalence of ECG pathological changes, higher P amplitude and Macruz index, longer P duration, longer both crude and corrected Q-T intervals and R-R intervals and shorter P-R segments and QRS intervals than that of the controls. On the other hand, P-R intervals and heart rates of the two groups were not significantly different. Among both the the exposed and control groups, values of P duration were significantly negatively correlated with that of P-R segment: r = -0.216 and -0.132, respectively, p greater than 0.05. Values of the ECG components were not related to duration of exposure to CDS. Moreover, no significant difference was observed between duration of exposure of the exposed workers with and of those without pathological ECG changes. The method used in our study may be useful in evaluating the ECG of exposed workers before the appearance of the known pathological abnormalities.

Critical daily dose of cadmium in residents in cadmium-polluted areas in Japan, were quite diverse by area. Some elucidations for the diversion shall be discussed based on our recent experimental data. 1) Aging aggravated cadmium health effects in rabbits. 2) Excessive dietary zinc and/or copper aggravated cadmium health effects in old animals, but did not in young animals. The effects were quite diverse by age. 3) Low-protein diet was a potent factors aggravating cadmium health effects especially in old rats. 4) It may be difficult, therefore, to estimate a single and unanimous critical daily dose of cadmium, but it is highly recommended for old residents in cadmium-polluted areas, and probably also for old cadmium workers, to avoid excessive exposure to zinc and/or copper, and to take enough protein to avoid aggravating cadmium health effects.

Potassium guaiacolsulphonate has been determined in a cough syrup by recording the second (D2) derivative absorption curve and taking D2 at 288 nn as a direct measure of its concentration. the mean percentage found from the labelled +SD was found to be 103.3+0.35. Added recovery experiments gave a mean percentage recovery of 100.3+0.24. the results were found to be in good agreement with those obtained using a spectro-fluorimetric method. the D2 method has been found to be reproducible with a relative standard deviation less than 1%.

Four two-component mixtures have been assayed using both Vierordt's and first derivative spectrophotometric methods. Such mixtures are acepifylline and phenobarbitone, phenylbutazone and amidopyrine, procaine and caffeine, and sulphamethoxazole and trimethoprim. These selected applications illustrate the relative ease and simplicity offered by first derivative spectrophotometry for the assay of two component mixtures with spectral interferences from matrix formulations.

A method is presented for the determination of procaine hydrochloride without prior separation from degradation products, using the combined polynomial method. Thus, pw (= 3p2 + 4p3) calculated over the wavelength range 272-316 nm at 4 nm intervals, using 12-point orthogonal polynomials, was linearly related to concentration (0.3-1.3 mg/100 mL), reproducible (rel. std dev. 0.88%), and independent of degradation products. Mean percent recovery for 6 mixtures of procaine hydrochloride and degradation products was 100.49 ± 1.33. The relationship log c% vs time for a solution in pH 10 buffer was linear with aslope of −0.171/day.

Plasma malondialdehyde (MDA) (an indicator of lipid peroxidation) was determined in random samples of workers (age range 25-60 years) exposed to silica dust (n = 31, mean exposure duration 21.3 +/- 8.3 years) or asbestos dust (n = 59, mean exposure duration 15.6 +/- 4.5 years) and in 52 age-matched healthy male controls. MDA levels of both exposed groups were significantly higher than that of the controls and were significantly higher among workers exposed to asbestos than among those exposed to silica dusts. Neither age nor smoking was related to MDA levels among both controls and exposed workers; among the latter group MDA was not significantly correlated with duration of exposure. Mean MDA levels of exposed workers with radiographic signs of lung fibrosis or pleural thickening and of those without such signs were not significantly different, except in the case of asbestos-exposed workers where it was significantly less than that of those without such signs. Differences between mean durations of dust exposure of workers with radiographic signs of lung fibrosis and those without such signs were statistically insignificant. The results suggest the possible involvement of lipid peroxidation on exposure to silica or asbestos dusts in humans and possible development of antioxidant mechanism(s) on prolonged dust exposure and support the opinion that development of pneumoconiosis depends on susceptibility factor(s).

Two-component spectrophotometric method of analysis using 2 wavelengths, the method of least squares using absorbances, the method using 2-orthogonal function coefficients, and the method of least squares using orthogonal function coefficients have been applied to the determination of atropine sulfate in the presence of phenylmercury (II) acetate, compounds whose spectra overlap. The first method gave erroneous results; the second method gave satisfactory results for synthetic mixtures. The fourth method was superior, especially in the presence of irrelevant absorption. It has been successfully used for determining atropine sulfate in injection solutions in which a cubic irrelevant absorption was present. Results were in good agreement with those obtained by the official method.

Dichlorophen, oxyphenbutazone, phenazone, methyldopa, isoprenaline sulfate, and salbutamol sulfate are reacted with sodium cobaltinitrite in aqueous acetic acid. The yellow color is measured at 365, 320, 320, 330, 425, and 325 nm in aqueous acetic acid, respectively, and at 445, 380, 375, 345, 325, and 412 nm in sodium hydroxide, respectively. The reaction product is extractable with CHC13, with a maximum absorption at 370 nm for dichlorophen, 355 nm for phenazone, and 325 nm for oxyphenbutazone. The method is applied to the determination of these drugs in tablet form. The results obtained are reasonably reproducible with a coefficient of variation less than 2%.

Tiaprofenic acid (Surgam®) has been determined directly by using differential pulse polarography (DPP) and pH 5.5 acetate buffer as a supporting electrolyte. The differential pulse polarogram was obtained under constant amplitude pulses of 50 mV superimposed on a linearly increasing dc ramp. Peak current was measured at the peak potential of — 0.990 V vs Ag/AgCl reference electrode. Under the experimental conditions used, a linear relationship between peak current and concentration was established over the range 0.5-5.0 ng/mL. Mean percentage recoveries for tiaprofenic acid in authentic and tablet forms were 100.27 ± 2.25 and 99.45 ± 1.44, respectively. The results obtained by the DPP method were compared with those of the spectrophotometric method used by the manufacturer for the analysis of tiaprofenic acid and its tablet form.

The increment method under least squares has been applied to the spectrophotometric determination of p-hydroxybenzoic acid complexed with polyvinylpyrrolidone in water. The mean percentage recovery for six prepared mixtures was found to be 99.49 + 1.25. When the Amax method has been applied, the mean percentage recovery was found to be 90.99+5.59. The theoretical bases of the method have been discussed.

The use of first derivative spectrophotometry for the simultaneous determination of certain drugs in multicomponent formulations is presented. The method is illustrated by the determination of antazoline hydrochloride, phenylephrine hydrochloride and ephedrine hydrochloride in eye drops and acepifylline, phenobarbitone and papaverine hydrochloride in suppositories. These selected applications illustrate the relative ease and simplicity offered by first derivative spectrophotometry for the assay of three-component mixtures with spectral interferences from matrix formulations.

The first-derivative curves of u.v.—visible spectra (ΔE/Δλ ) are useful in quantitative analysis. A base-line technique and its algebraic version are reported for (i) the correction of quadratic irrelevant absorption, and (ii) the determination of a substance in the presence of another with overlapping spectra. The method is illustrated by the determination of atropine sulphate in the presence of phenyl-mercury(II) nitrate. The results obtained suggest that the method warrants careful study over a wide field of applications.

A rapid method is presented for detection and determination of anhydrotetracycline- HCl (ATC-HC1) and 4-epianhydrotetracycline-HCl (4-EATC-HCl) in tetracycline-HCl (TC-HCl). The method determines the 2 compounds as a sum, not individually. The first derivative absorption curve has a trough (D1) at 460 nm which is linearly related to concentration (1-10 mg/mL). ATC-HC1 + 4-EATC-HCl content was determined in TC-HCl powder and capsules by the D1 and the compensation D1 spectrophotometric methods. The results were compared with those obtained using U.S. Pharmacopeia and British Pharmacopoeia methods