Application of Liquid-Liquid Extraction for the Determination of Antibiotics in the Foodstuff: Recent Trends and Developments.

Nowadays, the presence of antibiotic residues in foods with animal origin has become an important challenge for public health authorities in many countries. Antibiotic residues are associated with several health problems in the human body such as acute allergic or toxic reactions, chronic toxic effects, and disturption of the natural balance of intestinal microflora as well as the emergence of antimicrobial resistance pathogenic bacteria. In order to determine the trace levels of antibiotics in the foodstuff, the development of rapid, sensitive and accurate analytical methods is necessary. Besides the great advances in the development of analytical instruments in recent years, sample preparation remains a critical step of any analytical procedure. Since food samples have complex and heterogeneous matrices, the sample preparation method can affect the accuracy, precision and overall performance of an analytical technique. Liquid-liquid extraction (LLE) is one of the most commonly used techniques for sample preparation which allows the selective concentration of target analytes in the aqueous samples. The aim of this study was to provide an updated overview of the recent trends and development in LLE techniques over the past 5 years. Different variations of this method such as hollow fiber liquid-phase microextraction, dispersive liquid-liquid microextraction, salting-out LLE, and aqueous two-phase system extraction are given in the present study. This review is focused on recent innovations and modifications in the LLE procedure which try to improve the efficiency and safety of this technique.

Current trends in sample preparation by solid-phase extraction techniques for the determination of antibiotic residues in foodstuffs: a review.

The presence of antibiotic residues in foodstuff has been of growing concern in recent years. They are associated with several adverse effects on human health such as the transmission of antibiotic-resistant pathogenic bacteria through the contaminated food, weakness of the immune system, allergic or toxic reactions and imbalance of the gut microbiota. Therefore, monitoring of the levels of antibiotic residues in animal-derived food is necessary to guarantee the safety of food products as well as the public health. Since the residual antibiotics in the foodstuff are in trace levels which are often lower than the limits of detection of analytical instruments, the sample preparation before the analysis is very important. This step is an essential part of an analytical process, especially for the extraction of chemical residues from a sample, preconcentration of the extract and elimination of any matrix interferences that may affect the selectivity, sensitivity and the overall performance of the analytical methods. Solid-phase extraction (SPE) is one of the most widely used techniques for the sample preparation that provides an efficient and reproducible method for selective concentration of target analytes in complex matrices. The objective of this research was to provide an updated overview of the recent trends in SPE techniques over the past five years. Different variations of this method, including solid-phase microextraction, stir bar sorptive extraction, matrix solid-phase dispersion, micro-solid-phase extraction, dispersive micro solid-phase extraction, magnetic solid-phase extraction, and molecularly imprinted solid-phase extraction are also given in the present study. The review is focused on recent developments and innovations in the SPE which tries to improve the efficiency, safety and performance of sample preparation.

Evaluation the Effect of Amine Type on the Non-isothermally Derived Activation Energy for the Interaction of 3 Antidepressant Drugs with Lactose.

Purpose: Evaluation of drug-excipients compatibility is an important stage during preformulation studies. In the present research, differential scanning calorimetry (DSC) at different heating rates (2.5, 10, 15°C/min) was applied for the kinetic evaluation of fluvoxamine (FLM), sertraline (SER) and doxepin (DOX) binary mixtures with lactose. Methods: Solid state kinetic parameters of the mixtures were calculated using two different thermal methods including ASTM E698 and Starink and the effect of amine type (pKa value) was investigated based on the calculated activation energies. Results: Based on obtained results mean activation energy calculated for FLM, SER and DOX with lactose using ASTM E698 and Starink methods are equal to 335.23, 132.02 and 270.99 kJ/ mol respectively. Conclusion: Results showed that the probability of drug-lactose interaction is higher in the SERlactose mixture in comparison with other two antidepressant drugs which is consistent with their pKa values.

Physicochemical analysis and nonisothermal kinetic study of sertraline-lactose binary mixtures.

In the present study the physicochemical stability of sertraline with lactose was evaluated in drug-excipient binary mixtures. Different physicochemical methods such as differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy, and mass spectrometry were applied to confirm the incompatibility. The final aim of this study was to evaluate the kinetic parameters using a fast and sensitive DSC method. Solid-state kinetic parameters were derived from nonisothermally stressed physical mixtures using different thermal models such as Friedman, Flynn-Wall-Ozawa, and Kissinger-Akahira-Sunose. Overall, the instability of sertraline with lactose was successfully evaluated. Further confirmation was made by tracking the Maillard reaction product of sertraline and lactose by mass spectrometry. DSC scans provided important information about the stability of sertraline in solid-state condition and also revealed the related thermokinetic parameters in order to understand the nature of the chemical instability.

Thermal Stability and Kinetic Study of Fluvoxamine Stability in Binary Samples with Lactose.

Purpose: In the present study the incompatibility of FLM (fluvoxamine) with lactose in solid state mixtures was investigated. The compatibility was evaluated using different physicochemical methods such as differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR) spectroscopy and mass spectrometry. Methods: Non-Isothermally stressed physical mixtures were used to calculate the solid-state kinetic parameters. Different thermal models such as Friedman, Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) were used for the characterization of the drug-excipient interaction. Results: Overall, the incompatibility of FLM with lactose as a reducing carbohydrate was successfully evaluated and the activation energy of this interaction was calculated. Conclusion: In this research the lactose and FLM Maillard interaction was proved using physicochemical techniques including DSC and FTIR. It was shown that DSC- based kinetic analysis provides fast and versatile kinetic comparison of Arrhenius activation energies for different pharmaceutical samples.

Kinetics study of hydrochlorothiazide lactose liquid state interaction using conventional isothermal arrhenius method under basic and neutral conditions

ABSTRACT The Maillard reaction of hydrochlorothiazide (HCTZ) and lactose has been previously demonstrated in pharmaceutical formulations. In this study, the activation energy of - hydrohlorothiazide and lactose interaction in the liquid state was ascertained under basic and neutral conditions. Conventional isothermal High Performance Liquid Chromatography (HPLC) technique was employed to ascertain the kinetic parameters using Arrhenius method. Results: The activation energy obtained was 82.43 and 100.28 kJ/mol under basic and neutral conditions, respectively. Consequently, it can be inferred that Maillard reaction is significantly affected by pH, which can be used as a control factor whenever the reaction potentially occurs.

Investigation of Possible Maillard Reaction Between Acyclovir and Dextrose upon Dilution Prior to Parenteral Administration.

In this study the stability of parenteral acyclovir (ACV) when diluted in dextrose (DEX) as large volume intravenous fluid preparation (LVIF) was evaluated and the possible Maillard reaction adducts were monitored in the recommended infusion time. Different physicochemical methods were used to evaluate the Maillard reaction of dextrose with ACV to track the reaction in real infusion condition. Other large volume intravenous fluids were checked regarding the diluted drug stability profile. Differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and mass data proved the reaction of glucose with dextrose. A Maillard-specific high performance liquid chromatography (HPLC) method was used to track the reaction in real infusion condition in vitro. The nucleophilic reaction occurred in diluted parenteral preparations of acyclovir in 5% dextrose solutions. The best diluent solution was also selected as sodium chloride and introduced based on drug stability and also its adsorption onto different infusion sets (PVC or non PVC) to provide an acceptable administration protocol in clinical practices. Although, the Maillard reaction was proved and successfully tracked in diluted solutions, and the level of drug loss when diluted in dextrose was reported to be between 0.27 up to 1.03% of the initial content. There was no drug adsorption to common infusion sets. The best diluent for parenteral acyclovir is sodium chloride large volume intravenous fluid.

Filgrastim (G-CSF) loaded liposomes: mathematical modeling and optimization of encapsulation efficiency and particle size.

Introduction: Optimization of filgrastim (G-CSF) (granulocyte colony stimulating factor) liposomes formulation prepared by the method of film hydration was the aim of this research. Methods: To study the independent variables effects in the development of filgrastim (G-CSF) liposomes, method of factorial design was applied. The molar ratio of dipalmitoyl phophatidylcholine (DPPC) per cholesterol (Chol.) and hydration time were chosen as two independent factors. The dependent variables were encapsulation efficiency percent (EE %) and particle size (PS). Ultrafiltration method was applied for separation of un-encapsulated protein. RP-HPLC method was employed for analysis of G-CSF. Results: Application of response surface methodology (RSM) in formulation of filgrastim liposomes and the obtained results for responses including particle size and EE % showed that the main effective independent variable was DPPC/Chol molar ratio. Different impacts of influencing parameters including interaction and individual effects were checked employing a mathematical method for obtaining desired liposomes. Optimum liposomal formulations were established using this method for enhancing their characteristics. Average percent errors (APEs) were 3.86% and 3.27% for predicting EE % and PS, respectively which reflect high model ability in this regard. Conclusion: It is concluded that observed and predicted values regarding PS and EE % were consistent and this model is efficient enough in prediction of the mentioned characteristics while preparing filgrastim (G-CSF) liposomes.

Development and characterization of solid dispersion for dissolution improvement of furosemide by cogrinding method.

PURPOSE: The purpose of this study was to prepare and characterize solid dispersion formulation of furosemide to enhance dissolution rate. METHODS: Solid dispersions with different drug: carrier ratios were prepared by cogrinding method using crospovidone and microcrystalline cellulose as carrier. The physical state and interactions between the drug and carrier were characterized by Fourier transform infrared spectroscopic (FT-IR) and X ray diffraction (XRD). RESULTS: Solid dispersions (especially with drug: Carrier ratio of 1:2) showed a higher dissolution rate than their respective physical mixture and pure furosemide. Dissolution rate in pH 5.8 was also higher than pH 1.2. The XRD analysis showed that crystalline form was changed to the amorphous state in the solid dispersions. FT-IR analysis did not show any physicochemical interactions in the solid dispersion formulations. Release kinetic of formulations were fitted best to the Weibull and Wagner log probability (linear kinetic) as well as suggested 2 and Gompertz (non-linear kinetic) models. CONCLUSION: The dissolution properties of furosemide were improved with the use of hydrophilic carriers in solid dispersions due to change in the crystalline form of the drug and more intimate contact between drug and carriers which was dependent on the type and ratio of carrier as well as dissolution medium pH.

Development and characterization of solid dispersion of piroxicam for improvement of dissolution rate using hydrophilic carriers.

INTRODUCTION: The main objective of this study was preparation and characterization of solid dispersion of piroxicam to enhance its dissolution rate. METHODS: Solid dispersion formulations with different carriers including crospovidone, microcrystalline cellulose, Elaeagnus angustifolia fruit powder, with different drug to carrier ratios were prepared employing cogrinding method. Dissolution study of the piroxicam powders, physical mixtures and solid dispersions was performed in simulated gastric fluid and simulated intestinal fluid using USP Apparatus type II. The physical characterization of formulations were analyzed using powder X ray diffraction (PXRD), particle size analyzer and differential scanning calorimetry (DSC). Interactions between the drug and carriers were evaluated by Fourier transform infrared (FT-IR) spectroscopic method. RESULTS: It was revealed that all of three carriers increase the dissolution rate of piroxicam from physical mixtures and especially in solid dispersions compared to piroxicam pure and treated powders. PXRD and DSC results confirmed the reduction of crystalline form of piroxicam. FT-IR analysis did not show any physicochemical interaction between drug and carriers in the solid dispersion formulations. CONCLUSION: Dissolution rate was dependent on the type and ratio of drug to carrier as well as pH of dissolution medium. Dissolution data of formulations were fitted well into the linear Weibull as well as non-linear logistic and suggested models.

Determination of aflatoxins in nuts of Tabriz confectionaries by ELISA and HPLC methods.

PURPOSE: Aflatoxins (AFs) are a group of mycotoxins and secondary metabolites of various species of Aspergillus. There are various forms of aflatoxins including B1, B2, G1, G2, M1 and M2 types. Aflatoxins cause important health problems and have high potential effect on liver cancer. Therefore, numerous investigations have been conducted during last three decades. The aim of this work is to determine the contamination levels of nuts used by the confectionaries in Tabriz. METHOD: A total of 142 samples including 35 almond , 26 walnut, 4 seeds of apricot, 6 sunflower seeds kernel, 6 sesame seed, 6 peanuts , 32 pistachio,13 hazelnuts and 14 cashews samples were collected from Tabriz confectionaries. The ELISA method was employed for the screening of total aflatoxins. RESULT: In 13 cases (28.1% of pistachios, 5.1% of walnuts and 7.1% of cashews) contamination rate of higher than 15 ppb were observed. The HPLC method was applied for the confirmation of ELISA results. Aflatoxin B1 was the highest detected AFs. CONCLUSION: The overall results of the tested samples indicated that the rate of contamination of pistachios is higher than the other tested samples.

In vitro and in vivo evaluation of insulin microspheres containing protease inhibitor.

The aim of this study was to investigate the applicability of microspheres containing protease inhibitor for oral delivery of insulin (CAS 9004-10-8). Microspheres of insulin were prepared by water-in-oil-in-oil (w/o1/o2) double emulsion solvent evaporation method. Formulations with different drug/polymer ratios were prepared and characterized by drug loading, loading efficiency, yield, particle size, scanning electron microscopy (SEM), Fourier Transform Infrared spectroscopy (FTIR). The in vitro release studies were performed in pH 1.2 and 7.4. In vivo studies on rats were conducted in order to investigate the bioavailability and performance of oral microspheres. The best polymer to drug ratio in microspheres was 15.6:1 (F2 formulation). The loading efficiency was 77.36%, production yield was 54.55% and mean particle size was 222.4 microm. SEM studies showed that the microspheres were spherical and porous in nature. Data obtained from in vitro release were fitted to various kinetic models and high correlation was obtained in the first order model. The results of enzymatic degradation indicated that insulin could be protected from trypsinic degradation in the microspheres. Our results indicate that the microspheres containing aprotinin (CAS 9087-70-1) have the advantage of high loading efficiency, pH responsive and prolonged release carrying insulin to the optimum site of absorption as well as the enhanced insulin absorption and biological response.

Reciprocal powered time model for release kinetic analysis of ibuprofen solid dispersions in oleaster powder, microcrystalline cellulose and crospovidone.

PURPOSE: A physically sound derivation for reciprocal power time (RPT) model for kinetic of drug release is given. In order to enhance ibuprofen dissolution, its solid dispersions (SDs) prepared by cogrinding technique using crospovidone (CP), microcrystalline cellulose (MC) and oleaster powder (OP) as a novel carrier and the model applied to the drug release data. METHODS: The drug cogrounds with the carriers were prepared and subjected to the dissolution studies. For elucidation of observed in vitro differences, FT-IR spectroscopy, X-ray diffraction patterns, DSC thermograms and laser particle size measurement were conducted. RESULTS: All drug release data fitted very well to newly derived RPT model. The efficiency of the carriers for dissolution enhancement was in the order of: CP>OP>MC. The corresponding release kinetic parameter derived from the model, t50% (time required for 50% dissolution) for the carrier to drug ratio 2:1 were 2.7, 10.2 and 12.6 min, respectively. The efficiency of novel carrier, OP, was between CP and MC. FT-IR showed no interaction between the carriers and drug. The DSC thermograms and X-ray diffraction patterns revealed a slight reduced crystallinty in the SDs. Also grinding reduced mean particle size of drug from 150.7 to 44.4 microm. CONCLUSIONS: An improved derivation for RPT model was provided which the parameter of the model, t50%, unlike to previous derivations was related to the most important property of the drug i.e. its solubility. The model described very well drug release kinetics from the solid dispersions. Cogrinding was an effective technique in enhancing dissolution rate of ibuprofen. Elaeagnus angostifolia fruit powder was suggested as a novel potential hydrophilic carrier in preparing solid dispersion of ibuprofen.

Development of pH-sensitive insulin nanoparticles using Eudragit L100-55 and chitosan with different molecular weights.

Insulin is a polypeptide hormone and usually administered for treatment of diabetic patients subcutaneously. The aim of this study was to investigate the efficiency of enteric nanoparticles for oral delivery of insulin. Nanoparticles were formed by complex coacervation method using chitosan of various molecular weights. Nanoparticles were characterized by drug loading efficiency determination, particle size analysis, Scanning Electron Microscopy (SEM), Zeta potential and CD spectroscopy (Circular Dichrosim). The in vitro release studies were performed at pH 1.2 and 7.4. The drug loaded nanoparticles showed 3.38% of entrapment, loading efficiency of 30.56% and mean particle size of 199 nm. SEM studies showed that the nanoparticles are non-spherical. Zeta potential increased with increasing molecular weight of chitosan. The CD spectroscopy profiles indicated that the nano-encapsulation process did not significantly disrupt the internal structure of insulin; additionally, pH-sensitivity of nanoparticles was preserved and the insulin release was pH-dependent. These results suggest that the complex coacervation process using chitosan and Eudragit L100-55 polymers may provide a useful approach for entrapment of hydrophilic polypeptides without affecting their conformation.

Piroxicam nanoparticles for ocular delivery: physicochemical characterization and implementation in endotoxin-induced uveitis.

To investigate the anti-inflammatory impacts of piroxicam nanosuspension, in the current investigation, piroxicam:Eudragit RS100 nanoformulations were used to control inflammatory symptoms in the rabbits with endotoxin-induced uveitis (EIU). The nanoparticles of piroxicam:Eudragit RS100 was formulated using the solvent evaporation/extraction technique. The morphological and physicochemical characteristics of nanoparticles were studied using particle size analysis, X-ray crystallography, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). Drug release profiles were examined by fitting the data to the most common kinetic models. Selected nanosuspensions were used to assess the anti-inflammatory impacts of piroxicam nanoparticles in the rabbits with EIU. The major symptoms of EIU (i.e. inflammation and leukocytes numbers in the aqueous humor) were examined. All the prepared piroxicam formulations using Eudragit RS100 resulted in a nano-range size particles and displayed spherical smooth morphology with positively charged surface, however, the formulated particles of drug alone using same methodology failed to manifest such characteristics. The Eudragit RS100 containing nanoparticles displayed lower crystallinity than piroxicam with no chemical interactions between the drug and polymer molecules. Kinetically, the release profiles of piroxicam from nanoparticles appeared to fit best with the Weibull model and diffusion was the superior phenomenon. The in vivo examinations revealed that the inflammation can be inhibited by the drug:polymer nanosuspension more significantly than the microsuspension of drug alone in the rabbits with EIU. Upon these findings, we propose that the piroxicam:Eudragit RS100 nanosuspensions may be considered as an improved ocular delivery system for locally inhibition of inflammation.

The effect of type and concentration of vehicles on the dissolution rate of a poorly soluble drug (indomethacin) from liquisolid compacts.

PURPOSE: For poorly soluble, highly permeable (Class II) drugs, such as indomethacin, the rate of oral absorption is often controlled by the dissolution rate in the gastrointestinal tract. Therefore together with the permeability, the solubility and dissolution behaviour of a drug are key determinants of its oral bioavailability. The object of the present study is to increase dissolution rate of indomethacin using liquisolid compacts. METHODS: Several formulations of liquisolid compacts containing various ratios of drug: propylene glycol (ranging from 1:1 to 1:4) was prepared. In this study the ratio of microcrystalline cellulose (carrier) to silica (coating powder material) was 20 in all formulations. The dissolution behaviour of indomethacin from liquisolid compacts and conventional formulations was investigated at different pHs (1.2 and 7.2). RESULTS: The results showed that liquisolid compacts demonstrated considerably higher drug dissolution rates than those of conventionally made capsules and directly compressed tablets containing indomethacin. This was due to increased wetting properties and surface of drug available for dissolution. Also it has been shown that the fraction of molecularly dispersed drug (FM) in the liquid medication of liquisolid systems was directly proportional to their indomethacin dissolution rates (DR). An attempt was made to correlate the percentage drug dissolved in 10-min with the solubility of indomethacin in different vehicles. A plot of the percentage drug dissolved against the solubility of indomethacin showed that the amount of drug dissolved increased linearly (correlation coefficient of 0.9994 and 0.996 at pH 7.2 and 1.2 respectively) with an increase in solubility of indomethacin in the vehicles. CONCLUSION: The liquisolid compacts technique can be a promising alternative for the formulation of water insoluble drugs, such as indomethacin into rapid release tablets.

Development and evaluation of buccoadhesive propranolol hydrochloride tablet formulations: effect of fillers.

The buccal mucosa has been investigated for local and systemic delivery of therapeutic peptides and other drugs that are subjected to first-pass metabolism or are unstable within the rest of the gastrointestinal tract. Propranolol hydrochloride (propranolol HCl) is subjected to first-pass effect, therefore formulation of buccal-adhesive dosage form can circumvent this effect. The effect of lactose (a soluble excipient) and dicalcium phosphate (DCP) (an insoluble excipient) on dissolution rate, kinetic of release and adhesion force of buccal-adhesive tablets of propranolol HCl were evaluated. Each tablet composed of 80 mg propranolol HCl, 80 mg hydroxypropylmethylcellulose (HPMC) K4M, polycarbophil AA1 and lactose or DCP with different ratios. The results showed that the presence of the fillers increased dissolution rate of the drug. The release data also showed that the effect of lactose on the dissolution rate was greater than the DCP. Kinetic release of propranolol HCl from buccal-adhesive matrices was affected by the different ratios of polymers and fillers. The fillers reduced the bioadhesion force and this effect was more considerable in formulation containing DCP. In order to determine the mode of release, the data were analyzed based on the equation Q =kt(n). The results showed that an increase in the concentration of HPMC K4M resulted in a reduction in the value of n. The value of n was not significantly affected by an increase in the concentration of lactose or DCP. The values of n in this study were calculated to be between 0.461 and 0.619, indicating both diffusional release and erosional mechanism.