A simple and rapid reversed phase HPLC method was developed and validated for estimation of pregabalin from the surfaces of equipment used for pharmaceutical manufacturing. The chromatographic separation was achieved on Waters Symmetry Shield RP18 column (5.0 µm, RP18, 250 mm x 4.6 mm) at 40°C by using isocratic elution using methanol and sodium di hydrogen phosphate monohydrate buffer (pH adjusted to 6.30 with NaOH solution; 0.01M) at flow rate of 0.8 ml/min. UV detection was performed at 200 nm. Water was used as swabbing solvent to extract the drug residues from the stainless steel surface. Texwipe swabs (polyester swab) were used to remove the drug from the stainless steel surface. The method was validated for system suitability, specificity recovery, limit of detection, limit of quantification, linearity, ruggedness and robustness. The recovery values from stainless steel surface were found more than 93.5%. The limit of detection and limit of quantification were 0.20 µg/ml and 0.39 µg/ml respectively. Method was found precise at concentration level 0.3917 µg/ml. Method was found linear from 0.39 µg/ml to 2.7979 µg/ml. The coefficient of correlation was observed 0.9999.

The purpose of this study was to isolate and characterize alkaloids from the leaves of Alstonia macrophylla collected from Penang Island, Malaysia. Various chromatography methods, namely thin layer chromatography, column chromatography and centrifugal chromatography were used to isolate and purified extract. Identification of the isolated pure alkaloids was based on their spectral data and various spectroscopic methods. A total of 19 alkaloids were isolated, 15 alkaloids were characterized; the remaining four alkaloids were suspected as new derivative and subjected to be further elucidated. Eight out of 15 alkaloids isolated were varied with alkaloids reported in East Coast, Malaysia studies.

In the present study, a new and simple direct chiral HPLC method was developed and validated for the simultaneous enantiomeric separation of ezetimibe and tramadol. The enantiomeric separation was carried on Chiralpak-ASH analytical column (150 x 4.6 i.d mm, 3 µm) by using acetonitrile: methanol: diethyl amine: formic acid (99/1.0/0.1/0.1% v/v/v/v) as mobile phase. Solvent mixtures were delivered at a flow rate of 1.0 ml/min and peaks were detected at 225 nm. The retention time of R-EZT, S- EZT and S-TRA, R-TRA was found to be 2.12, 2.40 and 4.01, 4.50 min respectively. The calibration curve were plotted in the range of 2.0-10 µg/ml for R-EZT, S- EZT and 1.0-5.0 µg/ml for S-TRA, R-TRA respectively. The proposed method was validated as per the ICH guidelines and found to be specific, linear, selective, and precise. The obtained results indicated that the proposed method can be utilized for the simultaneous enantiomeric purity determination of ezetimibe and tramadol in active pharmaceutical ingredient and their pharmaceutical formulation.

The Piper caldense is a medicinal plant widely used to treat snake bites, as a sedative and for tooth pain. However, there are few reports about the biological potential of the plant and only two reports on its chemical composition. The objective of the present work was to determine the antimicrobial activity and chemical profiles of P. caldense tissues as well as to isolate their major compounds. The major compound 3-geranylgeranyl-4 hydroxybenzoic acid found in all plant tissues, showed antibacterial activity for all tested bacteria including those gram-positive and gram-negative, and especially against gram-positive Staphylococcus aureus, Bacillus subtilis, Enterococcus faecalis with minimum inhibitory concentration of 39.5 µg/mL. The compound was characterized based in the interpretations of spectra data of IR, MS, 1H and 13C NMR analysis and chemical profiles of plant tissues obtained by HPLC.