Biomedical subjects

R Pereira-Rosario

Publications and source records attributed to R Pereira-Rosario.

3 recordsLinked to original sources

PubMed1989

Diode array spectroscopy in pharmaceutical analysis: determination of acetaminophen/codeine phosphate tablets.

The use of diode array spectrophotometry for the analysis of tablets containing acetaminophen and codeine has been investigated. The technique was found to be applicable to the analysis of tablets which nominally contain 300 mg acetaminophen and 15, 30 or 60 mg codeine phosphate (Tylenol Nos 2-4, respectively). The concentration of codeine in extracts of Tylenol No. 1, which contains 7.5 mg codeine phosphate, was found to be too low for precise determination. First-derivative spectroscopy is required for the analysis of Tylenol Nos 2 and 3. Tylenol No. 4 can be determined using either the zero or the first-derivative spectra; however, the former was found to give consistently lower values for each component. The influence of derivative order and analytical wavelength range on the precision was investigated. The accuracy of the procedure was assessed by comparing the results from spectroscopy with those from liquid chromatography. Finally, some general conclusions on the applicability of diode array spectroscopy for the multicomponent analysis of pharmaceuticals are presented.

Acetaminophen↗

PubMed1988

The interaction of dopexamine with various drugs and excipients in parenteral solutions.

The interaction of dopexamine hydrochloride with various excipients and other drugs in parenteral solutions has been investigated by microcalorimetry. The interaction with heparin sodium, in particular, is significant. The interaction is strongest in parenterals containing glucose and is eliminated in normal saline. Divalent cations are more effective than monovalent ones in eliminating the reaction, which is apparently ionic in nature.

Calorimetry↗

PubMed1988

Interaction of heparin sodium and dopamine hydrochloride in admixtures studied by microcalorimetry.

Microcalorimetry was used to investigate the interaction between dopamine hydrochloride and heparin sodium in 5% dextrose injection and in 0.9% sodium chloride injection. Heat of reaction (in microjoules) was measured by flow calorimetry for the following combinations of solutions: dopamine hydrochloride solution and heparin sodium solution prepared from powdered forms of the drugs in water; solutions of the powdered drugs in 5% dextrose injection; solutions of the powdered drugs in 0.9% sodium chloride injection; solutions prepared in 5% dextrose injection from commercial dopamine hydrochloride injection and commercial heparin sodium injection; and solutions prepared in 0.9% sodium chloride injection from the commercial drug injections. Mixing the solutions of the powdered drugs in water caused heat to be evolved, as did mixing the solutions of the powdered drugs diluted with 5% dextrose injection and the commercial injections diluted with 5% dextrose injection. The interactions of the two drugs were believed to be ionic, based on the exothermic nature of the reaction. No heat of reaction was measurable when sodium chloride was used as the diluent. Based on this preliminary investigation, admixtures containing heparin sodium and dopamine hydrochloride should be mixed in 0.9% sodium chloride injection to minimize the risk of interaction between the two drugs.

Calorimetry↗