PubMed Health⌕ Search

Biomedical subjects

V Das Gupta

Publications and source records attributed to V Das Gupta.

At least 55 records · Page 3Linked to original sources
PubMed1984

Stability of cefsulodin in aqueous buffered solutions and some intravenous admixtures.

The stability of cefsulodin in aqueous solutions of various pH values, buffer concentrations, ionic strengths and intravenous admixtures were studied using a stability-indicating high-pressure liquid chromatography method. The pH range of optimum stability was determined to be 3.2-5.7. Cefsulodin was more stable on the acidic and less on the alkaline side as compared with most of the other cephalosporins such as cefoxitin (pH range of optimum stability approximately 4-7). In 5% dextrose and 0.9% sodium chloride injection, cefsulodin was stable (at least 90% potent) for about 1, 17 and at least 60 days at 24 degrees, 5 degrees and -10 degrees C, respectively.

Buffers↗
PubMed1984

Stability of dobutamine hydrochloride and verapamil hydrochloride in 0.9% sodium chloride and 5% dextrose injections.

The stability of dobutamine hydrochloride (250 micrograms/ml) and verapamil hydrochloride (160 micrograms/ml) alone and in combination in 0.9% sodium chloride injection or 5% dextrose injection was studied. Solutions were stored both in plastic i.v. bags and in amber-colored glass bottles at 24 degrees C and 5 degrees C for up to seven days. Before storage and at various times during storage, solutions were assayed at least in triplicate by high-performance liquid chromatography, pH was recorded, and visual appearance was noted. All solutions tested under all conditions retained at least 90% potency for seven days. In plastic i.v. bags, dobutamine either alone or in combination with verapamil in both diluents turned a light-pink color in 24 hours at 24 degrees C. The intensity of the pink color increased with time in 0.9% sodium chloride injection; in 5% dextrose injection, solutions, became clear in 48 hours. The pH of solutions prepared in plastic i.v. bags in 5% dextrose injection decreased from 4.0 to 3.1 during the seven-day period at 24 degrees C; results for solutions in amber bottles were similar. At 5 degrees C, the pH and clarity of all solutions in bags and bottles remained stable for seven days. At the concentrations tested, dobutamine hydrochloride combined with verapamil hydrochloride is stable in 0.9% sodium chloride injection and 5% dextrose injection for 48 hours at 24 degrees C and for seven days at 5 degrees C.

Catecholamines↗
PubMed1983

Complexation of procainamide with hydroxide-containing compounds.

The complexation of procainamide with hydroxide-containing compounds, ethanol, fructose, glucose, glycerin, lactose, maltose, propylene glycol, sorbitol, and sucrose, have been studied. Procainamide formed a complex with glucose, lactose, and maltose, all of which contain a hemiacetal group, whereas fructose and sucrose do not. The percent of complex formed was dependent on the pH of the solution, with an optimum range of approximately 4-5.2. As with glucose, the percent of complex formed was directly related to the concentration of lactose in the solution. In dry mixtures, procainamide did not form a complex with glucose or lactose. The complex formed with lactose or maltose could be completely reversed by adding hydrochloric acid. A similar observation with glucose was reported earlier. In the optimum pH range, equilibrium was established in approximately 24 hr, and the process of complexation followed the equation for reversible reactions.

Chemical Phenomena↗
PubMed1983

Quantitation of meperidine hydrochloride in pharmaceutical dosage forms by high-performance liquid chromatography.

A high-performance liquid chromatographic (HPLC) method for the quantitative determination of meperidine hydrochloride in pharmaceutical dosage forms was developed. The method is reproducible and precise with relative standard deviations (based on six readings) of 1.2% with hydroxyzine and 0.93% with hydroxyprogesterone caproate as the internal standards. A variety of other active and inactive ingredients which were mixed with meperidine hydrochloride did not interfere with the assay procedure. Among the ingredients tested were acetaminophen, atropine sulfate, disodium edetate, metacresol, phenol, promethazine, and sodium metabisulfite. This method appears to be stability-indicating since a hydrolyzed sample of meperidine showed zero potency and a new peak with a different retention time.

17 alpha-Hydroxyprogesterone Caproate↗
PubMed1982

Quantitation of hydroxyprogesterone caproate, medroxyprogesterone acetate, and progesterone by reversed-phase high-pressure liquid chromatography.

A high-pressure liquid chromatography method for the quantitation of hydroxyprogesterone caproate, medroxyprogesterone acetate, and progesterone in pharmaceutical dosage forms was developed. The method gave accurate, precise, and reproducible results. The excipients present in the dosage forms did not interfere with the assay procedure except benzyl benzoate in progesterone injection. The percent relative standard deviations based on six injections were 1.6, 2.5, 2.7% for hydroxyprogesterone caproate, medroxyprogesterone acetate, and progesterone, respectively. The stability of progesterone in ethanol--propylene glycol--water (10:50:40) was studied. The loss in potency of progesterone, even after 487 days of storage at 50 degrees, was less than 10%.

17 alpha-Hydroxyprogesterone Caproate↗
PubMed1982

Effect of some formulation adjuncts on the stability of benzoyl peroxide.

The stability of benzoyl peroxide in polyethylene glycol ointment base and some liquid vehicles (acetone, ethanol, propylene glycol, and their mixtures) was studied. Some solutions also contained an additional ingredient (acetanilide, benzoic acid, chlorhydroxyquinoline, and hydroxyquinoline) as a possible stabilizer. Benzoyl peroxide decomposed very fast (first-order K value 0.028 day-1 at 24 degrees) in polyethylene glycol ointment base. At 50 degrees, the potency of benzoyl peroxide in polyethylene glycol ointment base decreased to less than 1% in 5 days. Decomposition in solutions is complex. Considering acetone as a standard vehicle, ethanol improved the stability of benzoyl peroxide and propylene glycol had an adverse effect on the stability. Of the stabilizers studied, only chlorhydroxyquinoline improved the stability.

Benzoyl Peroxide↗
PubMed1982

Stability of haloperidol in 5% dextrose injection.

The stability of haloperidol in 5% dextrose injection using a high-pressure liquid chromatographic (HPLC) method is reported. A solution of haloperidol 10 mg/dl in 5% dextrose injection was prepared using commercially available haloperidol injection. The solution was stored at 24 degrees C, half in an amber glass bottle and half in a plastic bag. These were assayed on days 0, 1, 7, 14, and 38. Solutions prepared from commercial dosage forms of haloperidol (injection, oral liquid concentrate, and tablets) were assayed to verify the accuracy of the HPLC assay to quantify haloperidol. There was no loss of haloperidol potency in 38 days when stored 24 degrees C in either the amber glass bottle or plastic bag. There was a substantial loss of methylparaben and propylparaben (present in commercial haloperidol injection) in the solution stored in the plastic bag. Oxidation products of haloperidol did not interfere with the assay, and the HPLC assay accurately measured haloperidol in solutions prepared from commercial dosage forms. The results show that haloperidol 10 mg/dl in 5% dextrose injection was stable for at least 38 days. While the loss of parabens is not of practical importance, the HPLC method developed provided this information while the previously used USP-NF procedure did not. The assay can be used to quantify haloperidol in commercial dosage forms.

Chemistry, Pharmaceutical↗
PubMed1981

Stability of aqueous suspensions of disulfiram.

The stability of disulfiram in aqueous suspension is reported. Aqueous suspensions of disulfiram were prepared from bulk powder and from disulfiram tablets. Acacia and sodium benzoate were present in the suspension, the final concentration of which was 25 mg/ml disulfiram. Suspensions were stored in amber bottles under fluorescent light at 24 degrees C for 178 days (tablets) and 295 days (bulk powder). Samples were taken at various intervals during storage and assayed by high-pressure liquid chromatography (HPLC) and a modified NF method. Both types of suspension were stable. Potency remained constant, and no new peaks appeared in the chromatograph. Physical integrity of the suspensions was maintained. The suspension made from tablets contained less foam and air than the one made from bulk powder; both types were easily dispersible. A degradation product of disulfiram, diethyldithiocarbamic acid, did not interfere with the assay. The HPLC assay method was more reproducible than the modified NF method. Aqueous suspensions of disulfiram are stable at room temperature for the indicated time periods, and the HPLC assay method for disulfiram is reproducible and accurate.

Chromatography, High Pressure Liquid↗
PubMed1981

Stability of cefamandole nafate and cefoxitin sodium solutions.

High-pressure liquid chromatographic (HPLC) methods for the quantitative determinations of cefamandole, cefamandole nafate, and cefoxitin sodium were developed and used to study the stabilities of reconstituted solutions of the latter two antibiotics. Results from the HPLC procedures were compared with those from a previously reported colorimetric procedure. Solutions (2%) of cefamandole nafate and cefoxitin sodium in 0.9% sodium chloride injection and in 5% dextrose injection were studied at 24 degrees C and 5 degrees C. The colorimetric method, which is supposed to be specific for compounds with beta-lactam rings, gave misleading results because of the hydrolysis of the antibiotics. The results obtained by HPLC were reproducible and the procedure separated cefamandole, the hydrolyzed compound, from its ester (cefamandole nafate), which was essential for conducting these studies. The cefamandole solutions were stable for approximately five days at 24 degrees C and 44 days at 5 degrees C. The cefoxitin solutions were stable for 24 hours at 24 degrees C and for at least 13 days at 5 degrees C.

Cefamandole↗
PubMed1980

Simultaneous quantitation of acetaminophen, aspirin, caffeine, codeine phosphate, phenacetin, and salicylamide by high-pressure liquid chromatography.

A method for the simultaneous quantitation of acetaminophen, aspirin, caffeine, codeine phosphate, phenacetin, and salicylamide was developed. The method is based on reversed-phase high-pressure liquid chromatography with a mobile phase buffered with phosphate (pH 2.3). The procedure not only separated these six active ingredients but also salicylic acid, the major decomposition product of aspirin. The method gave excellent results for three commercial products and a synthetic mixture containing four active ingredients. Lowering the pH increased the retention time of some weak acids and decreased that of some weak bases. Only these changes in the retention times made the separation possible.

Acetaminophen↗
PubMed1980

High-pressure liquid chromatographic determination of salicylic acid in aspirin powder and pharmaceutical dosage forms.

A sensitive, simple, and rapid method for the quantitation of salicylic acid in aspirin powders and its dosage forms was developed. The method is based on reversed-phase high-pressure liquid chromatography using a mobile phase containing 20% methanol in aqueous phosphate buffer of pH 2.3. Other common ingredients present with aspirin such as acetaminophen, caffeine, codeine phosphate, phenacetin, and salicylamide do not interfere. Salicylic acid quantities as low as 0.1 microgram can be assayed with a relative standard deviation of +/- 2.3%. Sensitivity can be increased by using lower sensitivity settings. The method was tried on numerous commercial products and an old aspirin powder. The results generally were excellent, except that all of the aspirin and salicylic acid could not be extracted from suppositories. The old aspirin powder failed the USP limit test for salicylic acid. The powder apparently absorbed moisture and contained salicylamide as an impurity.

Aspirin↗
PubMed1980

Effect of pH, chlorobutanol, cysteine hydrochloride, ethylenediaminetetraacetic acid, propylene glycol, sodium metabisulfite, and sodium sulfite on furosemide stability in aqueous solutions.

A study was conducted to determine the effects of pH, two antioxidants, a chelating agent, a preservative, and propylene glycol on furosemide stability. Aqueous solutions of furosemide containing 10% alcohol (v/v) were prepared in phosphate buffers with various pH values (5, 6, and 9) whose ionic strength was adjusted to 0.1 M with potassium chloride. Some solutions contained chlorobutanol, ethylenediaminetetraacetic acid, or sodium metabisulfite. Another set of aqueous solutions contained phosphate buffer (0.1 M), alcohol (10% v/v), and propylene glycol (40% v/v) with or without cysteine hydrochloride, ethylenediaminetetraacetic acid, and sodium sulfite. The solutions were divided into two parts, stored at 24 and 50 degrees, and assayed frequently using a previously developed high-pressure liquid chromatographic procedure. At the lowest pH value (pH 5), furosemide appeared to be very unstable. Cysteine hydrochloride, ethylenediaminetetraacetic acid, and sodium sulfite failed to improve the stability of furosemide. Chlorobutanol and sodium metabisulfite had an adverse effect on the stability, probably due to the fact that they decreased the pH of the solution. The pH value appears to be the only critical factor for the stability of furosemide. Buffered solutions containing propylene glycol were very stable at both temperatures for 170 days, and they tasted good.

Chemical Phenomena↗
PubMed1980

Effect of pyridoxal 5-phosphate on carbidopa and decarboxylation of levodopa.

To study the interaction between enzymes and coenzymes and carbidopa and levodopa, a paired-ion high-pressure liquid chromatographic method was developed to separate carbidopa, dopamine, levodopa, and pyridoxal 5-phosphate. Carbidopa strongly reacted with pyridoxal 5-phosphate, contrary to a previous report. Tyrosine decarboxylase and tyrosine decarboxylase apoenzyme had some activity against levodopa, which could be increased by adding pyridoxal 5-phosphate to the mixture. This activity was inhibited by hydroxylamine hydrochloride.

Apoenzymes↗
PubMed1978

Stability of furosemide in aqueous systems.

A stability-indicating assay for furosemide based on high-pressure liquid chromatography was developed. The method is sensitive, accurate, and precise. The standard deviation based on six injections of the standard solution was +/- 1.37%. This method was used to study furosemide stability in various aqueous solutions and dosage forms. Stability tests were conducted at room temperature as well as at higher temperatures (45, 65, and 85 degrees) at various pH values and with different vehicles. Some decomposition products were identified.

Chromatography, High Pressure Liquid↗
PubMed1978

Quantitative determinations of two decongestants and an antihistamine in combination using paired ion high-pressure liquid chromatography.

A single method for the quantitative determinations of three active ingredients, phenylephrine hydrochloride, phenylpropanolamine hydrochloride, and brompheniramine maleate, and one inactive ingredient (sodium benzoate) in a commercial product for colds is reported. The method is based on paired ion high-pressure liquid chromatography using 1-heptanesulfonic acid as the counterion. It is accurate and precise. The relative standard deviations based on six readings are reported. This method is sensitive; less than 1 microgram of each ingredient can be assayed. The peak area of each ingredient is related to its concentration.

Brompheniramine↗