Liquid extraction and HPLC-DAD assay of hydrochlorothiazide from plasma for a bioequivalence study at the lowest therapeutic dose

Pharmaceutical importance of some promising plant species with special reference to the isolation and extraction of bioactive compounds: A review

BACKGROUND

Active principles from natural sources, in the form of extracts and natural compounds, provide an infinite number of bioactive compounds with consummate disposal of chemical diversity. These compounds and active principles are of utmost importance in the discovery of drugs of biological origin particularly, from plants.

OBJECTIVE

Development of resourceful technology for the isolation and extraction of bioactive compounds of medicinal importance is considered as an important task for researchers. There are a number of extraction, isolation, and characterization techniques currently utilized; however, most are laborious and use toxic chemicals and huge quantities of raw materials with a very low output. There are a number of abiotic and biotic factors that affects the quality and the quantity of plants bioactive compounds. Considering this the objectives of the current review is to discuss the various extraction and characterization techniques used to isolate the essential bioactive compounds from three plant species and the biotic and abiotic factors that affects the quantity and quality of the plants secondary metabolites.

METHODS

Many advanced technologies have been developed and tested for extraction, characterization, and their capacity for high yield products, and those requiring less application of toxic solvents are investigated continuously.

CONCLUSION

In this context, the present review summarizes the different types of extraction and characterization techniques utilized commercially by the food, drug, and pharmaceutical industries for better output and environmentally- and healthbenefiting products with special reference to three industrially important plants: Leonotis leonurus (L.) R.Br. (Lamiaceae) and Santalum album L. (Santalaceae) and Aloe vera (L.) Burm. f. (Aloaceae or Asphodelaceae).

Development of an HPLC-UV Method for the Analysis of Drugs Used for Combined Hypertension Therapy in Pharmaceutical Preparations and Human Plasma

A simple, rapid, and selective HPLC-UV method was developed for the determination of antihypertensive drug substances: amlodipine besilat (AML), olmesartan medoxomil (OLM), valsartan (VAL), and hydrochlorothiazide (HCT) in pharmaceuticals and plasma. These substances are mostly used as combinations. The combinations are found in various forms, especially in current pharmaceuticals as threesome components: OLM, AML, and HCT (combination I) and AML, VAL, and HCT (combination II). The separation was achieved by using an RP-CN column, and acetonitrile-methanol-10 mmol orthophosphoric acid pH 2.5 (7 : 13 : 80, v/v/v) was used as a mobile phase; the detector wavelength was set at 235 nm. The linear ranges were found as 0.1-18.5  μ g/mL, 0.4-25.6  μ g/mL, 0.3-15.5  μ g/mL, and 0.3-22  μ g/mL for AML, OLM, VAL, and HCT, respectively. In order to check the selectivity of the method for pharmaceutical preparations, forced degradation studies were carried out. According to the validation studies, the developed method was found to be reproducible and accurate as shown by RSD ≤6.1%, 5.7%, 6.9%, and 4.6% and relative mean error (RME) ≤10.6%, 5.8%, 6.5%, and 6.8% for AML, OLM, VAL, and HCT, respectively. Consequently, the method was applied to the analysis of tablets and plasma of the patients using drugs including those substances.

Determination of hydrochlorothiazide in human plasma by liquid chromatography/tandem mass spectrometry

In this study, a fast and sensitive liquid chromatography/tandem mass spectrometry method for determination of hydrochlorothiazide in human plasma was developed and validated. The analyte and irbesartan, used as the internal standard, were precipitated and extracted from plasma using methanol. Analysis was performed on a Phenomenex Kromasil C(8) column with water and methanol (27:73, v/v) as the mobile phase. Linearity was assessed from 0.78 to 200 ng/mL in plasma. The analytical method proved to be applicable in a pharmacokinetic study after oral administration of 12 mg hydrochlorothiazide tablets to 20 healthy volunteers.

Determination of captopril in human plasma, using solid phase extraction and high-performance liquid chromatography, coupled to mass spectrometry: Application to bioequivalence study

A specific high performance liquid chromatography-mass spectrometric (LC-MS/MS) assay was developed for the determination of captopryl in plasma. The retention time was 1.45 and 1.37 min for captopril and enalapril, respectively. The overall mean recovery, using SPE extraction with OASIS HLB cartridges, was found to be 107.2+/-9.5 and 100.04+/-2%, respectively. Calibration curves were linear in the concentration range of 10.00-2000.00 ng/ml, and the lower limit of quantification (LLOQ) was 10.00 ng/ml. The LLOQ was sensitive enough for detecting terminal phase concentrations of the drug. Inter-batch precision of the method ranged from 0.88 to 1.95%. Intra-batch accuracy ranged from 97.15 to 105.77%, while intra-batch precision ranged from 2.49 to 5.66% at concentrations of 30.00, 760.00 and 1500.00 ng/ml. The developed method was applied to study bioequivalence of captopril in a group of 25 human subjects at a single oral dose of a 50mg tablet.

Simultaneous determination of losartan, EXP-3174 and hydrochlorothiazide in plasma via fully automated 96-well-format-based solid-phase extraction and liquid chromatography–negative electrospray tandem mass spectrometry

An automated, sensitive and high-throughput liquid chromatographic/electrospray tandem mass spectrometric (LC-MS/MS) assay was developed for the simultaneous determination of losartan (LOS), its major circulating metabolite EXP-3174 and hydrochlorothiazide (HCTZ) in human plasma. LOS and HCTZ coexist in the same drug formulation, and this is the first method that enables the simultaneous determination of both drugs along with the active metabolite of LOS. Since these drugs have different physicochemical properties, the employment of a liquid-liquid extraction (LLE) protocol was precluded. A fully automated solid-phase extraction (SPE) protocol, based on 96-well format plates, was used to isolate these compounds and furosemide (internal standard, IS) from plasma. Washing and elution steps were amended accordingly in order to minimize any matrix effect from components of the plasma without reducing the elution of the molecules of interest. The compounds were eluted from a C18 column and detected with an API 3000 triple-quadrupole mass spectrometer using negative electrospray ionization and multiple reaction monitoring (MRM). The assay was linear over the range 1.00-400 ng/mL for LOS and EXP-3174 and 0.500-200 ng/mL for HCTZ, respectively, when 200 microl of plasma was used in the extraction. The overall intra- and interassay variations were within acceptance limits. The analysis time for each sample was 4 min, and more than 300 samples could be analyzed in one day by running the system overnight. The assay was simple, highly sensitive, selective, precise, fast, and it enables the reliable determination of LOS, EXP-3174 and HCTZ in pharmacokinetic or bioequivalence studies after per os administration of a single tablet containing both drugs.

Sensitive liquid chromatography-tandem mass spectrometry method for quantification of hydrochlorothiazide in human plasma

A simple, rapid, sensitive and specific liquid chromatography-tandem mass spectrometry method was developed and validated for quantification of hydrochlorothiazide (I), a common diuretic and anti-hypertensive agent. The analyte and internal standard, tamsulosin (II) were extracted by liquid-liquid extraction with diethyl ether-dichloromethane (70:30, v/v) using a Glas-Col Multi-Pulse Vortexer. The chromatographic separation was performed on a reversed-phase column (Waters symmetry C18) with a mobile phase of 10 mm ammonium acetate-methanol (15:85, v/v). The protonated analyte was quantitated in negative ionization by multiple reaction monitoring with a mass spectrometer. The mass transitions m/z 296.1 solidus in circle 205.0 and m/z 407.2 solidus in circle 184.9 were used to measure I and II, respectively. The assay exhibited a linear dynamic range of 0.5-200 ng/mL for hydrochlorothiazide in human plasma. The lower limit of quantitation was 500 pg/mL, with a relative standard deviation of less than 9%. Acceptable precision and accuracy were obtained for concentrations over the standard curve ranges. A run time of 2.5 min for each sample made it possible to analyze a throughput of more than 400 human plasma samples per day. The validated method has been successfully used to analyze human plasma samples for application in pharmacokinetic, bioavailability or bioequivalence studies.

Determination of cycloserine in human plasma by high-performance liquid chromatography with fluorescence detection, using derivatization with p-benzoquinone

A new method for determining cycloserine in plasma samples is described. This method is based on the derivatization of cycloserine with p-benzoquinone, a reaction that takes place at the same time as the process of plasma deproteinization due to the presence of ethanol as solvent in the solution of the derivatization reagent. Four derivatives are obtained from this reaction. The main derivative is well correlated with the cycloserine concentration. The ratio between the volumes of the plasma sample and the reagent solution is 1:2 for a p-benzoquinone concentration of 1000 microg/mL. Elution from a C18 column was isocratic, using a mobile phase containing (v/v) 85% aqueous 0.1% formic acid solution, and 15% (v/v) of a mixture of methanol and acetonitrile (1:1), with a flow-rate of 1 mL/min, at 25 degrees C. Determinations by fluorescence detection were achieved with excitation at 381 nm and emission at 450 nm, with a detection limit of 10 ng/mL for an injection volume of 5 microL. This method was validated and applied to the determination of cycloserine in blood plasma samples of several healthy volunteers.