Spectrophotometric Determination of Naproxen in Pure and Pharmaceutical Preparations

Environmental risk analysis of pharmaceuticals on freshwater phytoplankton assemblage: effects on alpha, beta, and taxonomic diversity

Antibiotics and nonsteroidal anti-inflammatory drugs (NSAIDs) have a wide range of bioactivities and are released into the ecosystem in large amounts. Heretofore, little information is available regarding their potential risk to the phytoplankton assemblage. Different alpha, taxonomic, and beta diversity measures were investigated and linked to the spatial variation of nine drugs. Distance-based redundancy analysis (dbRDA) indicated that pharmaceutical pollution had adverse effects on both phytoplankton diversity and taxonomic structure leading to the existence of congeneric taxa. However, different phytoplankton groups respond differently to different pharmaceuticals and Cyanoprokaryotes was suggested as the most sensitive group. According to the EC₅₀ value and the detected concentration for each drug, a hazard index (Hq) was calculated for each polluted site to investigate environmental risk analysis. Increasing Hq values exhibited negative effects on phytoplankton diversity. Phytoplankton community was characterized by high beta diversity values, which suggested that microalgae were able to disperse and select suitable environmental conditions. High beta diversity values were driven by species difference rather than species replacement due to the disappearance of most sensitive taxa from highly polluted sites. Additionally, microalgae were classified into different morpho-functional groups (FGs), and principal component analysis (PCA) indicated that different FGs had different responses to pharmaceutical pollution. A laboratory toxicity experiment was also conducted to identify the negative effects of short-term exposure to low doses of paracetamol and ciprofloxacin.

Micelle-enhanced spectrofluorimetric determination of diphenhydramine: application to human plasma and its simultaneous determination with naproxen in pharmaceutical tablets

Two simple and sensitive spectrofluorimetric methods were developed and validated for determination of diphenhydramine. The use of sodium dodecyl sulfate surfactant at pH 7 enhances the fluorescence intensity of diphenhydramine at 286 nm (method I) enabling its nanodetermination in biological samples with mean per cent recovery ± SD of 100.33 ± 1.519. Method I was validated according to ICH-Q2R1 guidelines and was successfully applied for determination of diphenhydramine in pharmaceutical dosage form and spiked human plasma in the concentration ranges 0.1-4.0 μg/mL and 0.2-1.0 μg/mL, respectively. Method I acted as a basis for the development of a first derivative synchronous spectrofluorimetry (method II) for simultaneous analysis of diphenhydramine and naproxen using a zero-crossing approach. Method II determines both drugs with linearity ranges of 0.05-3.0 μg/mL and 0.1-0.9 μg/mL for diphenhydramine and naproxen, respectively. The developed method was applied for the simultaneous determination of both drugs in their laboratory-prepared mixtures containing all expected excipients. Method II determines both drugs with a mean percent recovery ± SD of 100.56 ± 0.891 and 100.20 ± 1.125 for diphenhydramine and naproxen, respectively. The method was statistically compared with a reported method using Student's t- and F- tests, and no significant differences were observed.

Comparison between sodium dodecylsulphate and cetyltrimethylammonium bromide as mobile phases in the micellar liquid chromatography determination of non-steroidal anti-inflammatory drugs in pharmaceuticals

The retention behaviour of non-steroidal anti-inflammatory drugs (NSAIDs) using micellar mobile phases of sodium dodecylsulphate (SDS) is studied and compared with that observed with micellar mobile phases of cetyltrimethylammonium bromide (CTAB). A liquid chromatographic procedure for the determination of acemetacin, diclofenac, indomethacin, ketoprofen, naproxen and tolmetin in pharmaceutical preparations is described. The proposed system uses a Kromasil C18 analytical column and a solution of 0.15 M SDS at pH 3 with 10% 1-propanol as mobile phase. Under these conditions, the studied NSAIDs elute between 6 and 10 min at a 1 mL min(-1) flow rate. Limits of detection (LOD) are lower than 0.5 microg mL(-1). Recoveries in the analysis of the pharmaceutical preparations are ranged between 91 and 104% respect to the nominal content declared by the manufacturers and the relative standard deviations are in general lower than 4%.