[Determination of hydrazine in prednisolone by derivatization-gas chromatography-triple quadrupole mass spectrometry].

Prednisolone is an adrenal glucocorticoid drug with immunosuppressive, anti-inflammatory, anti-allergic, and antiviral effects that are widely exploited in clinical treatment. The hydrazine residue to prednisolone directly affects medication safety and threatens the patient's health. At present, there are no relevant laws, regulations, and standards to control the residual limit of hydrazine in drugs at home or abroad. Therefore, a simple, rapid, accurate, reliable, sensitive, and selective method is urgently needed for the determination of trace hydrazine in prednisolone. Hydrazine has strong polarity and reductivity, with unstable physical and chemical properties, thus being easily oxidized. In addition, because of the lack of chromophores and low molecular weight, the detection of hydrazine is very difficult. Therefore, a derivative reagent should be introduced to reduce its polarity and generate a derivative product with a high molecular weight as well as stable physical and chemical properties. Acetone, as a common laboratory reagent, is inexpensive and can rapidly react with hydrazine; therefore, it is an ideal derivative reagent for the determination of hydrazine. In this study, a method based on precolumn derivatization with gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS) was developed for the determination of hydrazine in prednisolone by optimizing the derivatization reagent, GC and MS conditions, solvent system, and derivatization conditions. Method validation was then carried out using the established method, and the results were satisfactory. In this study, 1 g of prednisolone sample was weighed and placed in a 10 mL centrifuge tube with a plug; then, a methanol-dichloromethane dilution solvent (14∶23, v/v) was added to the scale line, and the sample was vortexed until completely dissolved. About 100 µL of the test solution prepared above was pipetted into the sample vial, followed by the addition of 900 µL acetone. The resulting solution was vortexed and mixed well. The sample was diluted and derivatized simultaneously in acetone solution, acetone/methanol-dichloromethane dilution solvent (9∶1, v/v), and then detected and analyzed by GC-MS/MS. In this study, the derivatization reaction between hydrazine and acetone did not require the addition of acetic acid and ultrasound conditions, or the use of other reagents for the extraction operation. The reaction was instantaneous, and rapid determination of hydrazine in prednisolone could be achieved. The standard curve was obtained with a good correlation coefficient (r2=0.9999) in the range 1-12 µg/L. The limits of detection and quantitation were 0.03 mg/kg and 0.10 mg/kg, respectively. The relative standard deviation (RSD) of injection precision was 1.10%. The recoveries and repeatability were good; the recoveries of low-, medium-, and high-concentration spiked samples were 96.15%-96.46% at spiked concentrations of 1, 6, and 12 µg/L, respectively, and the corresponding RSDs were 1.77%-2.12%. The intermediate precision was good, and the RSD of the determination results obtained on the same instrument by different laboratory technicians at different times was 1.77%. The durability was good, and the degree of influence of the detection results was studied by changing the chromatographic conditions. Under the original condition or conditions with initial column temperature ±5 ℃, heating rate ±2 ℃/min, or column flow rate ±0.1 mL/min, the hydrazine content in the sample solution at a spiked concentration of 6 µg/L was detected, and the RSD of the detection results was 2.58%. The established method was applied to detect hydrazine in a prednisolone standard substance procured from the market and nine batches of prednisolone samples provided by a pharmaceutical company. No hydrazine was detected in any of these samples. The established method is simple, reliable, highly sensitive, and highly selective, and it can be applied for the detection of hydrazine in prednisolone.

Investigation of the urinary excretion of prednisolone and metabolites after nasal administration: Relevance to doping control.

Glucocorticosteroid use in sport is restricted to non-systemic (nasal/ophtamological/dermatological/intra-articular) use. Systemic use is prohibited because of strong inflammatory suppressing effects. Prednisolone is a GC proven to be very effective in the treatment of nasal congestions and allergic rhinitis and its therapeutic use is allowed. To establish normal urinary concentration ranges for nasally administered prednisolone, an excretion study was performed with Sofrasolone® (nasal-inhaler). Six volunteers were administered a high dose (4.5 mg prednisolone in four gifts over a 9-h period). Samples were analysed using a validated LC-MS/MS method monitoring prednisolone (PRED) and the metabolites prednisone (PREDON), 20ß-dihydroprednisolone (20ßPRED) and 20α-dihydroprednisolone (20αPRED) in the total fraction (glucuroconjugated and free). Maximum concentrations were 266, 500, 350 and 140 ng/ml for PRED, PREDON, 20ßPRED and 20αPRED, respectively. These results show that the current reporting limit of 30 ng/ml in urine can be easily exceeded after therapeutic use. Hence, to avoid false-positive findings related to nasal application, this limit should be increased. To investigate the degree of glucuronidation of PRED and its metabolites also the free fraction was investigated. This shows that PREDON has the highest glucuroconjugation (50%). PRED, 20ßPRED and 20αPRED only show less than 20% conjugation.

Determination of Endocrine Disrupting Chemicals in Water and Wastewater Samples by Liquid Chromatography-Negative Ion Electrospray Ionization-Tandem Mass Spectrometry.

A liquid chromatography-negative ion electrospray ionization-tandem mass spectrometry method was developed for the simultaneous analysis of bisphenol A, 4-octylphenol, 4-nonylphenol, diethylstilbestrol, 17ß-estradiol, estriol, estrone, 17α-ethinylestradiol, prednisone, and prednisolone. This method used solid-phase extraction with an elution solvent of acetonitrile to improve the stability of the analytes. To maintain the stability of analytes analyses were completed within five days. The recoveries ranged from 84 to 112% and the relative standard deviation of analysis of duplicate samples was <10%. The limits of quantitation were 1-10 ng/L. Surface water and wastewater were obtained from five wastewater treatment plants in Saskatchewan. Matrix effects were moderate to severe. Using standard addition calibration, all analytes except diethylstilbestrol and 17α-ethinyl estradiol were detected. There was a low frequency of detection of the target analytes in upstream and downstream water, indicating good removal efficiency during the wastewater treatment process. Bisphenol A and 4-nonylphenol were the only analytes detected downstream. Bisphenol A was the most frequently detected in raw wastewater (133 to 403 ng/L). Estriol was detected more often in raw wastewater than estrone or 17ß-estradiol. This is the first Canadian study with the detection of prednisone and prednisolone with concentrations at 198-350 ng/L in raw wastewater at 60% of the wastewater treatment plants.

A paper-based analytical device coupled with electrochemical detection for the determination of dexamethasone and prednisolone in adulterated traditional medicines.

The adulteration of herbal medicines by dexamethasone or prednisolone is regarded as a serious problem in many communities. Herein, a novel platform for the separation and quantification of both target steroids in herbal medicines based on electrochemical paper-based analytical devices (ePADs) has been created. The ePAD was composed of Whatman SG81 chromatography paper, 3D-printed devices and a commercial screen-printed electrode. Whatman SG81 silica-coated paper was used for the separation of dexamethasone and prednisolone based on the difference in their partition coefficients during the flow of the mobile phase. The optimal mobile phase was composed of 60% ethyl acetate in cyclohexane and required 7 min for separation. The separated steroids on the paper were then quantified by electrochemical detection using differential pulse voltammetry, in which the 3D-printed devices facilitated the measurement. Analytical detection ranges of 10-500 µg mL-1 were obtained for both dexamethasone and prednisolone (r2 = 0.988 and 0.994, respectively). The limits of detection for dexamethasone and prednisolone were 3.59 and 11.98 µg mL-1, respectively, whereas the limits of quantification were 6.00 and 20.02 µg mL-1, respectively. The amounts of both target steroids derived from real herbal medicine samples determined by the proposed method were comparable to those obtained with assays using standard high-performance liquid chromatography. In addition, a simple evaporation step can be used to increase the concentration of the samples before analysis. These ePADs are simple, low-cost, rapid, and very promising for on-site quantitative detection.

Prednisone may rebuild the immunologic homeostasis: Alteration of Th17 and Treg cells in the lymphocytes from rats' spleens after treated with prednisone-containing serum.

BACKGROUND: This study aimed to investigate alterations of T helper 17 (Th17), regulatory T (Treg) cells and relative cytokines after treating with prednisone-contained serum. Lymphocytes were isolated from female rats' spleens. METHODS: The splenic lymphocytes were divided into four groups: which were treated with normal rats' serum (control); prednisone-containing rats' serum (PDN); normal rats' serum and cytokines (CTK); cytokines and prednisone-containing rats' serum (PDN + CTK). The mRNA expression level of RORC, Foxp3 and interleukin-17 (IL-17) was examined by reverse transcription-polymerase chain reaction. The quantities of Th17 and Treg cells were tested by flow cytometry, and the concentrations of IL-17 and IL-10 were detected by enzyme-linked immunosorbent assay. RESULTS: Higher mRNA expression level of Foxp3, percentages of Treg/CD4+ , and concentrations of IL-10, lower mRNA expressions of RORC and IL-17, concentrations of IL-17 and percentages of Th17/CD4+ in PDN group were detected, compared with control group (all p < 0.01). Similar trend was detected in PDN + CTK group, compared with CTK group (all p < 0.01). CONCLUSION: Our results suggest that prednisone may rebuild the immunologic homeostasis and may be used in human diseases with changes in the imbalance immune system such as unexplained recurrent spontaneous abortion (URSA), hepatitis B infection, or other autoimmune diseases.

Selective and Sensitive Chromatographic Methods for Determination of a Co-Formulated Binary Mixture in Antibacterial Eye Drops and Aqueous Humor in the Presence of Their Degradation Products and Potential Impurities.

Prednisolone acetate (PDN) is a corticosteroid anti-inflammatory liable to degradation under different conditions and used with antibiotics in eye drops. Two selective stability-indicating separation techniques were developed for simultaneous determination of PDN and moxifloxacin HCl (MXF) binary mixture in pure forms, ophthalmic formulation, in the presence of PDN impurities and in the presence of their degradation products. The first method was based on HPTLC separation using silica gel 60 F254 HPTLC plates, and a developing system of toluene: ethyl acetate: methanol: ammonia (5.0: 6: 2.0: 0.05, v/v/v/v) is used with detection at 254 nm. The second method was HPLC using a mobile phase of acetonitrile: methanol: deionized water, pH 2.8 (25.0: 35.0: 40.0, v/v/v), at 254 nm. A kinetic study utilizing the developed HPLC method for PDN degradation under different stress conditions was performed. Furthermore, the method was applied for determination in rabbit aqueous humor. Validation was conducted as per ICH guidelines, and system suitability was ascertained. The calibration curves were constructed in the range 0.10-25.00 and 0.20-50.00 µg band-1, for PDN and MXF by HPTLC, while for HPLC, it was 0.02-50.00 and 0.10-50.00 µg mL-1 for both drugs, in order.

Automation of ionic liquid enhanced membrane bag-assisted-liquid-phase microextraction with liquid chromatography-tandem mass spectrometry for determination of glucocorticoids in water.

A novel fully automated liquid-phase microextraction (LPME) procedure making use of a conical polypropylene membrane bag to hold the solvent, coupled with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) with positive electrospray ionisation was developed to determine glucocorticoids (including cortisol, cortisone, dexamethasone, prednisone and prednisolone) in water. The solvent was a synergistic mixture of 10% v/v of ionic liquid, 1-butyl-3-methylimidazolium methylsulfate in n-octanol. The use of ionic liquid as an additive enhanced the extraction performance due to the favourable ionic and hydrogen bonding interactions with the analytes. Different experimental parameters such as the types of organic solvent as supported liquid membrane and ionic liquid, various composition of ionic liquid, volume of extractant phase, agitation time and speed, temperature of extraction were investigated. Under the most favourable extraction conditions, enrichment factors of 49.4-83.1 were obtained for the target compounds with relative standard deviations of <10%. The intra-day repeatability of the method ranged from 4.23 to 6.42% and the inter-day reproducibility ranged from 6.87 to 9.20%. Good linearity 0.05-50 ng mL-1 (prednisolone) and 0.1-50 ng mL-1 (all other analytes) with coefficients of determination of 0.991 or better, was obtained. The membrane bag-assisted-LPME UHPLC-MS/MS approach exhibited high sensitivity, linearity and repeatability for the extraction of the glucocorticoids and also offered an automated streamlined process, from the point where analytes were extracted, to the final analysis of the water samples. The method was employed to determine the concentration of these contaminants in the influent and effluent of a wastewater treatment plant.

Corticosteroids in liver and urine in Sicilian cattle by a LC-MS/MS method.

The presence of corticosteroid residues was assessed in urine and liver samples from livestock of Sicily. A total of 630 bovine samples were collected from farms and slaughterhouses. The samples were analysed using solid-phase extraction (SPE) coupled with ultra-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). All the corticosteroids found were under the maximum residue limit imposed by Commission Regulation (EC) 37/2010. About 4% of liver samples showed dexamethasone levels above the limit of detection (LOD), with a mean of 1.5 ± 0.2 µg kg-1. Betamethasone was found only in seven liver samples, with a mean of 1.6 ± 0.1 µg kg-1. Furthermore, prednisolone and prednisone were found only in urine and liver samples from slaughterhouse, probably related to the high rate of stress for bovines. These results suggest good control practices adopted by Sicilian farms, able to ensure the quality of food products.

Optimization of photo-Fenton process for the treatment of prednisolone.

Prednisolone is a widely prescribed synthetic glucocorticoid and stated to be toxic to a number of non-target aquatic organisms. Its extensive consumption generates environmental concern due to its detection in wastewater samples at concentrations ranged from ng/L to µg/L that requests the application of suitable degradation processes. Regarding the actual treatment options, advanced oxidation processes (AOPs) are presented as a viable alternative. In this work, the comparison in terms of pollutant removal and energetic efficiencies, between different AOPs such as Fenton (F), photo-Fenton (UV/F), photolysis (UV), and hydrogen peroxide/photolysis (UV/H2O2), was carried out. Light diode emission (LED) was the selected source to provide the UV radiation. The UV/F process revealed the best performance, reaching high levels of both degradation and mineralization with low energy consumption. Its optimization was conducted and the operational parameters were iron and H2O2 concentrations and the working volume. Using the response surface methodology with the Box-Behnken design, the effect of independent variables and their interactions on the process response were effectively evaluated. Different responses were analyzed taking into account the prednisolone removal (TOC and drug abatements) and the energy consumptions associated. The obtained model showed an improvement of the UV/F process when treating smaller volumes and when adding high concentrations of H2O2 and Fe2+. The validation of this model was successfully carried out, having only 5% of discrepancy between the model and the experimental results. Finally, the performance of the process when having a real wastewater matrix was also tested, achieving complete mineralization and detoxification after 8 h. In addition, prednisolone degradation products were identified. Finally, the obtained low energy permitted to confirm the viability of the process.

Simultaneous Determination of Gatifloxacin and Prednisolone in their Bulk Powder, Synthetic Mixture and Their Combined Ophthalmic Preparation Using Micellar Liquid Chromatography.

A simple rapid and accurate micellar high performance liquid chromatographic method was improved and validated for the analysis of mixture containing gatifloxacin sesquihydrate (GTF) and prednisolone acetate (PRED) in their synthetic mixture and their combined preparation. The separation was achieved using a C18 column, micellar mobile phase consisted of 0.2 M sodium dodecyl sulfate, 12.5% n-propanol and 0.3% triethylamine in 0.02 M orthophosphoric acid at pH 7.0 at a flow rate of 1 ml/min with UV detection at 270 nm. The proposed method was found to be rectilinear over the concentration ranges of 5.0-45 µg ml-1 and 10-50 µg ml-1 with recovery percentage of 99.95 ± 0.82 and 100.07 ± 0.84 for GTF and PRED, respectively. The separation of both drugs was accomplished in a very short chromatographic run (<5 min), the method is reproducible (R.S.D. < 1.0%) and show satisfactory resolution between GTF and PRED (Rs) = 1.67. The developed method was validated according to International Conference on Harmonization (ICH) guidelines. The limit of detection of the proposed method was 0.33 and 0.21 µg ml-1, and the limit of quantitation was 0.99 and 0.64 µg ml-1 for GTF and PRED, respectively.

Validated Chromatographic Methods for the Simultaneous Determination of Sulfacetamide Sodium and Prednisolone Acetate in their Ophthalmic Suspension.

Two specific, sensitive, rapid and accurate chromatographic methods have been developed, optimized and validated for the simultaneous determination of sulfacetamide sodium and prednisolone acetate in pure forms and in their binary mixture. The first method is an isocratic Reversed phase-high performance liquid chromatography method where a rapid separation was achieved on a Zorbax ODS column using a green mobile phase of methanol: water (80:20, v/v) and pH adjusted to 5.0 ± 0.2 with orthophosphoric acid. The retention times (tR) were 2.21 and 3.64 min for sulfacetamide sodium and prednisolone acetate, respectively. The separated peaks were detected at 254 nm. The second method is a thin layer chromatography-densitometric method where the two drugs were separated on silica gel plates using a simple mobile phase of chloroform: methanol (90:10, v/v) and scanning of the separated bands was at 254 nm. The retardation factors (Rf) values were 0.37 and 0.64 for sulfacetamide sodium and prednisolone acetate, respectively. The suggested methods were validated in compliance with the ICH guidelines and were successfully applied to determine both drugs in their pure forms, laboratory prepared mixtures and dosage form. The obtained results were statistically compared to the official method where no significant difference was obtained with respect to both accuracy and precision.

In vitro dissolution testing of parenteral aqueous solutions and oily suspensions of paracetamol and prednisolone.

The number of intramuscularly applied dosage forms has been continuously increasing during the last decades. However, up to date no in vitro dissolution test method for parenteral dosage forms has been described in the Ph. Eur. or USP. It was the aim of this study to investigate dissolution test setups based on the compendial flow-through cell and the reciprocating holder for this purpose. Both apparatuses were equipped with dialysis membranes to accommodate the drug formulation. The suitability of the dissolution method was evaluated by comparing release profiles with blood level curves that were obtained previously in an in vivo study in rats by our group. Aqueous solutions and oily suspensions of paracetamol and prednisolone were tested in vitro that were also applied in the in vivo study. In the case of the aqueous solutions in which no formal dissolution occurs, transport from the applied depot across a dialysis membrane was investigated. While the drug transport across the dialysis membrane of both drugs in aqueous solution was similar in all applied test methods, differences in the release behavior of paracetamol and prednisolone as an oily suspension were observed. This was mainly due to sedimentation of the particles within the oily depot.

Development and Validation of Eco-Friendly Liquid Chromatographic and Spectrophotometric Methods for Simultaneous Determination of Coformulated Drugs: Phenylephrine Hydrochloride and Prednisolone Acetate.

Five simple, sensitive, and eco-friendly LC and UV spectrophotometric methods have been developed for the simultaneous determination of phenylephrine hydrochloride (PHE) and prednisolone acetate (PRD) in their combined dosage form. The first method was reversed-phase (RP) LC using methanol-water-heptane-1-sulfonic acid sodium salt (75 + 25 + 0.1, v/v/w) as a mobile phase. Separation was achieved using an XSelect HSS reversed-phase C18 analytical column (250 × 4.6 mm, 5µm). The flow rate was 1.0 mL/min and UV detection was done at 230 nm. Quantification was achieved over the concentration ranges of 5-50 µg/mL for PHE and 2-90 µg/mL for PRD. Four spectrophotometric methods were proposed, namely dual wavelength, first derivative of ratio spectra, ratio difference, and mean-centering of ratio spectra. Linearity was observed in the concentration ranges of 10-120 and 5-35 µg/mL for PHE and PRD, respectively, for the spectrophotometric methods. Green solvents were used in the proposed methods because they play a vital role in the analytical methods' influence on the environment. The suggested methods were validated regarding linearity, accuracy, and precision according to the International Conference on Harmonization guidelines, with satisfactory results. These methods could be used as harmless substitutes for routine analysis of the mentioned drugs, with no interference from excipients.

Application of a handheld NIR spectrometer in prediction of drug content in inkjet printed orodispersible formulations containing prednisolone and levothyroxine.

Quality control tools to assess the quality of printable orodispersible formulations are yet to be defined. Four different orodispersible dosage forms containing two poorly soluble drugs, levothyroxine and prednisolone, were produced on two different edible substrates by piezoelectric inkjet printing. Square shaped units of 4cm2 were printed in different resolutions to achieve an escalating drug dose by highly accurate and uniform displacement of droplets in picoliter range from the printhead onto the substrates. In addition, the stability of drug inks in a course of 24h as well as the mechanical properties and disintegration behavior of the printed units were examined. A compact handheld near-infrared (NIR) spectral device in the range of 1550-1950nm was used for quantitative estimation of the drug amount in printed formulations. The spectral data was treated with mean centering, Savitzky-Golay filtering and a third derivative approach. Principal component analysis (PCA) and orthogonal partial least squares (OPLS) regression were applied to build predictive models for quality control of the printed dosage forms. The accurate tuning of the dose in each formulation was confirmed by UV spectrophotometry for prednisolone (0.43-1.95mg with R2=0.999) and high performance liquid chromatography for levothyroxine (0.15-0.86mg with R2=0.997). It was verified that the models were capable of clustering and predicting the drug dose in the formulations with both Q2 and R2Y values between 0.94-0.99.

Bovine teeth as a novel matrix for the control of the food chain: liquid chromatography-tandem mass spectrometry detection of treatments with prednisolone, dexamethasone, estradiol, nandrolone and seven ß2-agonists.

Veterinary drugs usually have rapid clearance rates in the liver and kidney, hampering their detection in conventional matrices such as the liver or urine. Pharmacological principles such as esterification may be applied to facilitate the administration of veterinary drugs and increase drug half-life. Prednisolone, whose therapeutic administration is regulated for food producing animals in the EU, is available in its acetate form as well as nandrolone, a banned anabolic steroid, which may be obtained as nandrolone phenylpropionate and estradiol as a benzoyl ester. While the distribution and accumulation of lipophilic and hydrophilic substances in human teeth have been well documented, studies on residues in bovine teeth are lacking. We hypothesised that analysis of bovine teeth could be used to detect both regulated and banned veterinary drugs. Steroids may be illegally used as growth promoters in food producing animals, alone or combined with ß2-agonists; therefore, we developed, and validated, in accordance with the Commission Decision 2002/657/EC, two analytical confirmatory LC-MS/MS methods to detect these classes of compounds following a unique liquid extraction procedure. Finally, we analysed teeth from three male Friesian veal calves treated with intramuscular estradiol benzoate, oral prednisolone acetate or intramuscular nandrolone phenylpropionate in combination with oral ractopamine, respectively, and from seven bovines from the food chain. Teeth from treated animals were positive for their respective drugs, with the exception of nandrolone phenylpropionate. One sample from a food chain bovine was positive for isoxsuprine, one of the seven ß2-agonists studied. Non-esterified forms of the steroids were not found. These results demonstrate that bovine teeth are a suitable matrix for the determination of pseudoendogenous substances or illicit administration of veterinary drugs.

Environmental concentrations of prednisolone alter visually mediated responses during early life stages of zebrafish (Danio rerio).

The development of the eye in vertebrates is dependent upon glucocorticoid signalling, however, specific components of the eye are sensitive to synthetic glucocorticoids. The presence of synthetic glucocorticoids within the aquatic environment may therefore have important consequences for fish, which are heavily reliant upon vision for mediating several key behaviours. The potential ethological impact of synthetic glucocorticoid oculotoxicity however has yet to be studied. Physiological and behavioural responses which are dependent upon vision were selected to investigate the possible toxicity of prednisolone, a commonly occurring synthetic glucocorticoid within the environment, during early life stages of zebrafish. Although exposure to prednisolone did not alter the morphology of the external eye, aggregation of melanin within the skin in response to increasing light levels was impeded and embryos exposed to prednisolone (10 µg/l) maintained a darkened phenotype. Exposure to prednisolone also increased the preference of embryos for a dark environment within a light dark box test in a concentration dependent manner. However the ability of embryos to detect motion appeared unaffected by prednisolone. Therefore, while significant effects were detected in several processes mediated by vision, changes occurred in a manner which suggest that vision was in itself unaffected by prednisolone. Neurological and endocrinological changes during early ontogeny are considered as likely candidates for future investigation.

Synthesis of lab-in-a-pipette-tip extraction using hydrophilic nano-sized dummy molecularly imprinted polymer for purification and analysis of prednisolone.

A novel pipette-tip based on nano-sized dummy molecularly imprinted polymer (PT-DMIP) assisted by ultrasonication for the effective enrichment and analysis of prednisolone from urine samples was developed. The PT-DMIP cartridge was prepared by packing the dummy molecularly imprinted polymer at the tip of the micropipette. The polymerization used betamethasone (BM) as the dummy template, 3-aminopropyltrimethoxysilane (APTMS) as the functionalized monomer, tetraethyl orthosilicate (TEOS) as the cross-linker and aluminum ion (Al(3+)) as a dopant to produce Lewis acid sites in the silica matrix for metal coordinative interactions with the analyte. Compared to conventional solid phase extraction (SPE), the PT-DMIP is cost-effective, fast, and easy to handle, while the system is very approachable and reduces the consumption of toxic organic solvent. HPLC-UV analysis revealed successful applicability of the sorbent for highly efficient extraction of perdnisolone from urine matrices. The extraction recovery was investigated and optimum conditions were obtained using central composite design. Good linearity for prednisolone in the range of 0.22-220µgL(-1) with regression coefficients of 0.99 reveals high applicability of the method for trace analysis. Under the optimized conditions, the recoveries are 89.0-96.1 with relative standard deviations (RSD) of less than 9.0%.

Computation of geometric representation of novel spectrophotometric methods used for the analysis of minor components in pharmaceutical preparations.

Novel spectrophotometric methods were applied for the determination of the minor component tetryzoline HCl (TZH) in its ternary mixture with ofloxacin (OFX) and prednisolone acetate (PA) in the ratio of (1:5:7.5), and in its binary mixture with sodium cromoglicate (SCG) in the ratio of (1:80). The novel spectrophotometric methods determined the minor component (TZH) successfully in the two selected mixtures by computing the geometrical relationship of either standard addition or subtraction. The novel spectrophotometric methods are: geometrical amplitude modulation (GAM), geometrical induced amplitude modulation (GIAM), ratio H-point standard addition method (RHPSAM) and compensated area under the curve (CAUC). The proposed methods were successfully applied for the determination of the minor component TZH below its concentration range. The methods were validated as per ICH guidelines where accuracy, repeatability, inter-day precision and robustness were found to be within the acceptable limits. The results obtained from the proposed methods were statistically compared with official ones where no significant difference was observed. No difference was observed between the obtained results when compared to the reported HPLC method, which proved that the developed methods could be alternative to HPLC techniques in quality control laboratories.

Suitability of bovine bile compared to urine for detection of free, sulfate and glucuronate boldenone, androstadienedione, cortisol, cortisone, prednisolone, prednisone and dexamethasone by LC-MS/MS.

The administration of boldenone and androstadienedione to cattle is forbidden in the European Union, while prednisolone is permitted for therapeutic purposes. They are pseudoendogenous substances (endogenously produced under certain circumstances). The commonly used matrices in control analyses are urine or liver. With the aim of improving the residue controls, we previously validated a method for steroid analysis in bile. We now compare urine (a 'classic' matrix) to bile, both collected at the slaughterhouse, to understand whether the detection of steroids in the latter is easier. With the aim of having clearer results, we tested the presence of the synthetic corticosteroid dexamethasone. The results show that bile does not substantially improve the detection of boldenone, or its conjugates, prednisolone and prednisone. Dexamethasone, instead, was found in 10 out of 53 bovine bile samples, but only in one urine sample from the same animals. Bile could constitute a novel matrix for the analysis of residues in food-producing animals, and possibly not only of synthetic corticosteroids.

Comparative study of novel versus conventional two-wavelength spectrophotometric methods for analysis of spectrally overlapping binary mixture.

Smart spectrophotometric methods have been applied and validated for the simultaneous determination of a binary mixture of chloramphenicol (CPL) and prednisolone acetate (PA) without preliminary separation. Two novel methods have been developed; the first method depends upon advanced absorbance subtraction (AAS), while the other method relies on advanced amplitude modulation (AAM); in addition to the well established dual wavelength (DW), ratio difference (RD) and constant center coupled with spectrum subtraction (CC-SS) methods. Accuracy, precision and linearity ranges of these methods were determined. Moreover, selectivity was assessed by analyzing synthetic mixtures of both drugs. The proposed methods were successfully applied to the assay of drugs in their pharmaceutical formulations. No interference was observed from common additives and the validity of the methods was tested. The obtained results have been statistically compared to that of official spectrophotometric methods to give a conclusion that there is no significant difference between the proposed methods and the official ones with respect to accuracy and precision.