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Biomedical subjects

V Das Gupta

Publications and source records attributed to V Das Gupta.

At least 19 recordsLinked to original sources
PubMed1992

Stability of captopril in some aqueous systems.

A stability-indicating high performance liquid chromatographic method has been proposed to quantify captopril. The method has been used to determine the stability of captopril in oral liquid dosage forms prepared from either commercially available tablets or powder. The dosage forms in water were more stable than when the vehicle was a syrup. Furthermore, the dosage form prepared using powder in water was more stable than when tablets were used. While the decomposition of captopril followed first-order equation when the dosage forms were prepared in syrup (in two of the three solutions studied), this equation was not followed when water was the vehicle. This is probably due to an uncontrolled factor, oxygen, because captopril is very sensitive to oxidation. Captopril solution prepared in water using tablets was stable for about 20 days when stored at 5 degrees C, and that prepared using powder in water was stable for about 27 days. One commercial syrup hastened the process of decomposition with an additional unidentified product of decomposition.

Captopril↗
PubMed1992

Development of a stable oral liquid dosage form of spironolactone.

A clear, stable, oral liquid dosage form of spironolactone has been developed. Solubility profiles of spironolactone were obtained in several co-solvent blends. Using this data, a co-solvent blend containing polyethylene glycol 400 (30% v/v), propylene glycol (10% v/v), glycerin (10% v/v) and ethyl alcohol (10% v/v) was used to solubilize spironolactone at a concentration of 2 mg/ml. The final formulation contained sweetening agents (sucrose, saccharin sodium), flavours (cherry, sweet), a desensitizing agent (menthol), a dye (FD&C Red #40) and a preservative (benzoic acid) to incorporate the desired organoleptic and preservative properties. A phosphate buffer was used to maintain a pH value of 4.5 (pH of maximum stability as reported earlier) to minimize hydrolysis. The final dosage form was stable for at least 93 days at 40 degrees C (loss of potency less than 4%). According to FDA guidelines, a tentative expiration date of 2 years at 25 degrees C is justifiable.

Administration, Oral↗
PubMed1991

Stabilities of dobutamine, dopamine, nitroglycerin and sodium nitroprusside in disposable plastic syringes.

The solutions of dobutamine hydrochloride (5 mg/ml), dopamine hydrochloride (4 mg/ml), nitroglycerin (1 mg/ml) and sodium nitroprusside (1 mg/ml) in dextrose 5% injection were stable for 24 h when stored at 25 degrees C in 60-ml plastic syringes. For sodium nitroprusside, the syringes must be wrapped with aluminium foil (provided by the manufacturer), otherwise the loss in potency is very high (22%). There was no change in the pH values of dobutamine and dopamine solutions as well as sodium nitroprusside solutions in the prewrapped syringes. However, the pH value of nitroglycerin solutions decreased to 4.3 from 4.6 and that of sodium nitroprusside solutions in unwrapped syringes from 4.2 to 3.5; these solutions had discoloured. The chromatogram also showed new peaks from the products of decomposition. The physical appearances of the other solutions did not change.

Chromatography, High Pressure Liquid↗
PubMed1991

Stability of cefuroxime axetil in suspensions.

Cefuroxime axetil is a mixture of two equally active isomers (50% each). A stability-indicating high-pressure liquid chromatography method for the quantification of cefuroxime axetil has been developed. The method is accurate, precise and reproducible. The percentage, relative standard deviation based on six injections was 1.2. Using the developed method, the chemical stability of cefuroxime axetil suspensions has been determined in three vehicles containing sugar and two without sugar. The results varied widely in the vehicles without sugar (up to +/- 31%). In the viscous vehicles containing sugar, the variations in the results were only up to +/- 6%. The cefuroxime axetil in these suspensions was stable up to 28 days when stored at 5 degrees C. In addition, pH values were stable and the physical appearances of the samples did not change.

Cefuroxime↗
PubMed1990

Development of oral liquid dosage forms of acetazolamide.

Two oral liquid dosage forms of acetazolamide have been developed. Using the solubility profiles, polyethylene glycol 400 (7%, v/v) was used as the solubilizing agent and propylene glycol (53%, v/v) as the cosolvent to keep acetazolamide in solution. Because of the bitter taste of acetazolamide, sweetening agents (simple syrup, sorbitol solution, and artificial sweeteners) and flavors (raspberry, sweet, and menthol) were added to the final formulations. A buffer (either phosphate or citrate) solution was used to maintain a pH value of 4 (pH of maximum stability as reported earlier) to minimize hydrolysis. The final dosage forms were stable for at least 90 days at 37 degrees C (loss of potency of 5%). According to FDA guidelines, a tentative expiry date of 2 years at 25 degrees C is justifiable.

Acetazolamide↗
PubMed1990

Chemical stability of cefotetan disodium in 5% dextrose and 0.9% sodium chloride injections.

The chemical stability of cefotetan disodium in 5% dextrose and 0.9% sodium chloride injections has been studied using a stability-indicating high-pressure liquid chromatographic (HPLC) assay method. The drug appears to be relatively unstable at 25 degrees C (expiry time 2 days), compared with at least 41 days at 5 degrees C and at least 60 days at -10 degrees C. Thawing the frozen samples in a microwave (90 s) did not cause any significant decomposition. The manufacturer's recommended expiry time of 4 days at 5 degrees C and at least 7 days at -10 degrees C is very conservative. The HPLC method developed is accurate and precise with a relative percentage standard deviation of 1.7 based on six readings. The method appears to be stability-indicating as the samples decomposed under drastic conditions had almost no drug left and new peaks were observed in the chromatograms.

Cefotetan↗
PubMed1990

Effect of excipients on the stability of levothyroxine sodium tablets.

Levothyroxine sodium tablets from two different manufacturers were analysed using the USP-NF method of analysis, a stability-indicating high pressure liquid chromatographic (HPLC) procedure. The results indicate that one particular manufacturer's 0.2-mg pink tablets contain some excipient(s) which act as a catalyst to hasten decomposition after extraction of levothyroxine for analysis. The same tablets from a different batch showed an additional long peak in the chromatogram, which indicated that the excipient(s) may have been changed. The same manufacturer has also used three different types of bottles/lids for the same product during the last year. Good manufacturing practice requires that new compatibilities/stability studies be conducted to assure the quality of the product. Ongoing stability studies are required by the Food and Drugs Administration (FDA). The use-life of 0.2-mg pink tablets of this manufacturer may be short.

17 alpha-Hydroxyprogesterone Caproate↗
PubMed1989

Stability of acyclovir sodium in dextrose and sodium chloride injections.

The chemical stability of acyclovir sodium in dextrose 5% w/v and sodium chloride 0.9% w/v injections has been studied using a stability-indicating high-pressure liquid chromatographic (HPLC) method. The drug appears to be very stable in both admixtures. There was no decomposition after 37 days of storage at 25 degrees C or 5 degrees C. The manufacturer-recommended expiry date of 24 h at 25 degrees C is too conservative. The solutions were clear throughout the study period and the pH values had decreased slightly in both the solutions. Acyclovir appears to be very stable on the alkaline side of the pH range and less so on the acidic side. There was no loss in the potency of acyclovir when mixed with dobutamine and dopamine.

Acyclovir↗
PubMed1988

Chemical stabilities of isoetharine hydrochloride, metaproterenol sulphate and terbutaline sulphate after mixing with normal saline for respiratory therapy.

The chemical stabilities of isoetharine hydrochloride inhalation solution, metaproterenol sulphate inhalation solution and terbutaline sulphate injection, after diluting 1 in 10 with sodium chloride 0.9% injection were studied. On storing the solutions in amber-coloured syringes, they were stable for at least 120 days at 5 degrees C. At 25 degrees C they were also stable for 120 days except that isoetharine solution discoloured and lost 7.8% of its potency after 90 days of storage. There was a new peak in the chromatogram from the decomposition product. All other solutions remained clear for 120 days at both temperatures. The initial and final pH values were similar except that after 120 days at both temperatures. The initial and final pH values were similar except that after 120 days at 25 degrees C, the pH value of terbutaline solution had increased from 4.9 to 5.4.

Amino Alcohols↗
PubMed1988

Colorimetric determination of tobramycin in parenteral solutions.

A colorimetric method based on a reaction between tobramycin and alkaline copper sulphate solution has been proposed to quantify tobramycin in injections. The excipients present and normal saline did not interfere with the assay procedure. A tobramycin sample which was decomposed using either sulphuric acid or sodium hydroxide solution indicated fairly good stability on both sides of the pH scale.

Colorimetry↗
PubMed1988

Chemical stabilities of cefoperazone sodium and ceftazidime in 5% dextrose and 0.9% sodium chloride injections.

The chemical stabilities of cefoperazone and ceftazidime solutions in 5% dextrose and 0.9% sodium chloride injections have been studied using high-performance liquid chromatography methods. The solutions of cefoperazone were stable for 8 days (loss in potency of less than 10%) at 25 degrees C, for at least 80 days at 5 degrees C and for at least 96 days at -10 degrees C. The ceftazidime solutions were stable for only 2 days at 25 degrees C, for 21 days at 5 degrees C (28 days in normal saline) and for 90 days at -10 degrees C. Thawing the frozen solutions using a microwave oven did not cause degradation.

Cefoperazone↗
PubMed1988

Chemical stabilities of famotidine and ranitidine hydrochloride in intravenous admixtures.

The chemical stabilities of famotidine and ranitidine hydrochloride solutions in 5% dextrose and 0.9% sodium chloride injections have been studied using high-performance liquid chromatographic methods (HPLC). Both the drugs were stable for at least 15 days (loss in potency of less than 10%) at 25 degrees C and 63 days at 5 degrees C. Both drugs were comparatively less stable in 5% dextrose injection than in 0.9% sodium chloride injection. The loss in the potency of phenol, which is added as a preservative to ranitidine hydrochloride injection, was significant in both the vehicles. However, the addition of preservative in a single dose vial is not considered necessary.

Chromatography, High Pressure Liquid↗
PubMed1987

Chemical stability of thiopental sodium injection in disposable plastic syringes.

The chemical stability of thiopental sodium injection (2.5%) when stored at 25 degrees and 5 degrees in disposable plastic syringes of two manufacturers (Monoject and Becton Dickenson and Co.) has been studied using the USP-NF method. The injection appeared to be stable for five days at 25 degrees and 45 days at 5 degrees with a loss in potency of less than 7%. The thiopental sodium did not adsorb on the syringes. The pH values and the physical appearance did not change. An additional peak was obtained in the chromatogram from both the freshly prepared and the assay solution probably due to an impurity in the powder.

Disposable Equipment↗
PubMed1986

Stability of cefuroxime sodium in some aqueous buffered solutions and intravenous admixtures.

Cefuroxime sodium (Zinacef) is a new semisynthetic, broad spectrum cephalosporin antibiotic for parenteral administration which is stable to most of the beta-lactamases. The stability of cefuroxime sodium in aqueous solutions, with or without phosphate buffer, and in 5% dextrose and 0.9% sodium chloride injections was studied using a stability-indicating high-pressure liquid chromatographic method developed in our laboratory. The optimum pH range of stability was determined to be approximately 4.5-7.3. Both buffered and unbuffered solutions followed first-order decomposition. In 5% dextrose and 0.9% sodium chloride injections, cefuroxime was stable for 1 day (more than 90% potent) at 25 degrees C and for at least 30 days at 5 degrees C. At -10 degrees C, there was negligible decomposition after 30 days. The pH values of the solutions stored at 5 degrees C and -10 degrees C remained in the maximum stability range and the solutions were clear even after 30 days of storage. Thawing the frozen solutions in a microwave oven adversely affected the stability.

Buffers↗
PubMed1986

Stability of hydralazine hydrochloride in aqueous vehicles.

The stability of hydralazine hydrochloride in aqueous vehicles which contain either dextrose, fructose, lactose, maltose, mannitol, sorbitol or sucrose has been studied using a stability-indicating high-performance liquid chromatographic method. Dextrose, fructose, lactose and maltose had adverse effects on the stability of hydralazine. In mannitol (better than sorbitol) and sorbitol, hydralazine was stable for about 21 days (loss in potency of less than 10%) and sucrose had an adverse effect only after its hydrolysis to fructose and dextrose. The optimum pH range of stability in dextrose was approximately between 3.2 and 4.4. The first-order rate of decomposition increased with an increase in the concentration of dextrose but not with an increase in the concentration of hydralazine. In the absence of other excipients the phosphate and citrate buffers did not adversely affect the stability of hydralazine hydrochloride.

Chromatography, High Pressure Liquid↗