Instrument implementation of an automated complex for recording physiological parameters of drivers

Goal of research: creation of an automated complex for quick and effective identification of an unacceptable condition of drivers before going to run and predicting their physiological state during a work shift. To achieve this goal in the creation of devices for the automated complex the following methods were used: photoplethysmographic method, pulse oximetric method, thermometric method. In the course of the research, results were achieved that make it possible to record physiological parameters of drivers with high reliability. This is achieved thanks to the use of the “isobestic point” photoplethysmogram in the registration at a length of 805 nm, the use of a two-channel pulse oximeter at wavelengths of 660 nm and 910 nm.

SIMULTANEOUS UV SPECTROPHOTOMETRIC METHODS FOR ESTIMATION OF CEFADROXIL AND PROBENECID IN TABLET DOSAGE FORM

Two methods for simultaneous estimation of Cefadroxil and Probenecid in combined tablet dosage form have been developed. The first UV spectrophotometric method was a determination using the simultaneous equation method at 233 nm and 247 nm. The second UV spectrophotometric method is the Q – analysis (absorption ratio) method, which involves the formation of absorbance equation at 242 nm (Isobestic point) and at 247 nm the maximum absorption of Probenecid . The linearity ranges for Cefadroxil and Probenecid both were 10-60μg/ml respectively. The accuracy of the methods was assessed by recovery studies was found to be 99.43±0.75 and 99.69±0.40 for simultaneous equation method and 99.23±0.34 and 99.56±0.16 for absorption ratio method for Cefadroxil and Probenecid respectively. These methods are simple, accurate and rapid; those require no preliminary separation and can therefore be used for routine analysis of both drugs in quality control laboratories.

Spectroscopic Determination of Aspirin and Omeprazole by Absorbance Ratio and Multicomponent Mode Method

Here we describe a simple, rapid and accurate method for simultaneous assay of aspirin and omeprazole. The first method was Absorbance ratio method (Method 1) and second method was multi component mode method of analysis (Method 2). Methanol: water (8:2) was used as solvent for both methods, using 293 nm as isobestic point for absorbance ratio method. The wavelength ranges 275.80 nm for aspirin and 302.20 nm for omeprazole for method 2, which represents the absorbance maxima of both drugs respectively. Beer’s law was applied in the concentration ranges of 2-14μg/mL and 2-18 μg/mL for aspirin and omeprazole, respectively, in absorbance ratio methods. The percentage assay was found to be in the range 99.74 to 100 % for aspirin and 99.69 to 99.9 % for omeprazole for both the methods. Recovery was found in the range of 99.74 –100.14 % for aspirin and omeprazole for both methods. The analysis data has been validated statistically and recovery studies confirmed the accuracy and reproducibility of the proposed methods, which were carried out according to the ICH guidelines.

Q- ABSORPTION RA TIO AND SIMULTANEOUS EQ UATION SPECTROPHOTOMETRIC METHODS FOR SIMULTANEOUS ESTIMATION OF FENBENDAZOLE AND NICLOSAMIDE IN PURE DRUG AND PHARMACEUTICAL FORMULATIONS

Two simple, accurate, sensitive and economical spectrophotometric methods have been developed and subsequently validated for determination of fenbendazole (FEN) and niclosamide (NIC) in bulk and pharmaceutical formulation. For the simultaneous equation method, the estimation of FEN and NIC was carried out at 227nm (λmax of FEN) and 332nm (λmax of NIC), respectively. For Q - absorption ratio method, estimation of FEN was carried out at 227nm (λmax of FEN) and of NIC at 306 nm (isobestic point of both drugs). Calibration curves of FEN and NIC were found to be linear in the concentration ranges of 3-9 ?g/mL and 10-30 ?g/mL, respectively, with their correlation coefficient values (r2 ) being more than 0.995. In the precision study, the % RSD value was found within limits (RSD < 2%). The percentage recovery at various concentration levels varied from 99.81 to 100 % for FEN and 99.86 to 100 % for NIC confirming that the projected methods are termed as an accurate and it can be applied successfully for the simultaneous estimation of FEN and NIC in pure and pharmaceutical dosage form.

Simultaneous UV Spectrophotometric Determination of Cetrizine and Dextromethorphan in Tablet Dosage Form

Two accurate, precise, sensitve and economical procedures for simultaneous estimation of cetrizine and dextromethorphan in tablet dosage forms have been developed. First method employs formation and solving of simultaneous equations using 230 nm and 280 nm as two analytical wavelengths for both drugs in methanol. The second method isQ-analysis based on measurement of absorptivity at 224 nm (as isobestic point) and 280 nm (λmaxof CTZ). Cetrizine and dextromethorphan at their respective λmax280 nm and 230 nm and at 224 nm (isobestic point) shows linearity in a concentration range of 10-30 mcg/mL for both the drugs. The recovery studies confirmed accuracy of the proposed methods and low values of standard deviation confirmed precision of the methods. The methods were validated as per ICH guidelines.

Study of the Large-Dimensional Hubbard Model Via a New Nonperturbative Method

A new nonperturbative method calculating the one-particle Green's function is introduced and applied to the Hubbard model. We show the metal–insulator transition in the paramagnetic ground state of the half-filled Hubbard model on a Bethe lattice with infinite connectivity. This method describes the transition regime appropriately. The analytic result using the continued fraction formalism which has a close relationship with present formalism is provided for comparison. As for the Hubbard model with doping, we obtain the optical conductivities and show the interesting features, such as midinfrared band and isobestic point. We also show that the sharp frequency-dependent behavior at large doping is the dispersed Drude type in this model.

Effects of Tissue Protectants on the Kinetics of Lactate Dehydrogenase in Cells

We studied the effects of two tissue protectants, polyvinyl alcohol (PVA) and agarose gel, on a kinetic parameter of lactate dehydrogenase LDH that is assumed to be related to the extent of diffusion of the enzyme out of tissue sections during its histochemical assay. The kinetics of the enzyme in mouse gastrocnemius (skeletal) muscle fibers and periportal hepatocytes were determined in unfixed sections incubated either on substrate (l-lactate)-containing agarose gel films or in aqueous assay media in the presence or absence of 18% PVA. The absorbances of the formazan final reaction products at their isobestic point were measured continuously in the cytoplasm of individual cells as a function of incubation time, using a real-time image analysis system. Whichever incubation medium was used, the absorbances in the two cell types increased nonlinearly during the first minute of incubation but linearly for incubation times between 1 and 3 min. The nonlinearity of the LDH reaction was analyzed using the equation vi - v = a° A, where vi is the observed initial velocity determined from the absorbance changes during the first 10 sec of incubation and v and ° A are respectively the gradient and intercept on the absorbance axis of the linear regression line of the absorbance on incubation times between 1 and 3 min. The plots of the observed ( vi - v) against ° A were linear. Their gradients a were characteristic for each cell type and tissue protectant. The a values for skeletal muscle fibers were 12–43% lower than those for hepatocytes. The a value for hepatocytes obtained with the PVA method was 32% lower than that determined with the gel film method. For skeletal muscle fibers, the a values determined by the two methods were almost the same. Addition of excess pyruvate to the aqueous assay medium had no effects on a for either muscle fibers or hepatocytes. In contrast, a was zero for sections of polyacrylamide gels containing purified enzyme, whether incubated on agarose films or in PVA media. These data confirmed that the constant a is related to the extent to which the enzyme diffuses out of sections during incubation but not to product inhibition of LDH by pyruvate. PVA was more effective for protecting diffusion of LDH from hepatocytes than from skeletal muscle fibers, possibly because hepatocytes contain a greater proportion of diffusable (unbound) LDH than skeletal muscle fibers.

Flash-Induced Electrochromic Band Shifts, is It a Simple Mechanism?

The flash-induced carotenoid bandshifts have been studied for various strains of both Rho-dopseudomonas sphaeroides and capsulata. A technique for calculating shifts of isobestic points down to 0.05 nm is described. To this end, special attention has been paid to the appropriate correction for reaction center absorbance changes occuring concommitantly with the carotenoid bandshifts. Plots of the wavelength of the isobestic point versus the corresponding absorption changes at the maximum of the difference spectrum have been made, suggesting the existence of different pools of carotenoids. The various pools of carotenoids seem to have different sizes, inducing non-linearities in the plots. In some cases spectral differences of the pools have to be assumed. A possible interpretation of the results would be that each electrogenic span of the electron transport chain is to be associated with its own pool of carotenoids, all the pools behaving in somewhat independant way. We discuss possible difficulties in making those measurements.