Antibacterial and cytotoxicity evaluation of Arum hygrophilum Bioss

OBJECTIVE

Arum hygrophilum Bioss is a plant native to Asia, Europe, and Northern Africa. It is consumed as beverages, spices, or cooked leaves to cure gastrointestinal infections and cancer. This study aims to determine the antibacterial and anticancer effectivenesss of A. hygrophilum Bioss.

MATERIALS AND METHODS

Using the well-diffusion method, the antimicrobial activity of the plant's aqueous extract and five other organic extracts were evaluated against bacteria often associated with food poisoning. The assessment of the antiproliferative activity by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was done on five cancerous cell lines and on fibroblasts as a reference cell line.

RESULTS

The growth of L. monocytogenes was significantly inhibited by the aqueous and ethanolic extracts. Both extracts had a minimum inhibitory concentration (MIC) of 62.5 mg/mL. The inhibition caused by the methanolic extract had a MIC of 500 mg/mL. The growth of S. aureus and MRSA were inhibited by the aqueous extract with a MIC of 500 mg/mL, while the inhibition caused by the ethanolic extract had a MIC of 250 mg/mL on MRSA and 500 mg/mL on S.aureus. Both strains of S.aureus were also inhibited by the 3-pentanon extract, while the butanol extract only exhibited a moderate growth inhibition against MRSA. The MTT assay showed that the aqueous extract had not affected the proliferation of cancer cell lines. The cytotoxicity of the ethanolic and methanolic extracts had no concentration-inhibition relationship and the IC50 values were above 800 μg/mL for all extracts.

CONCLUSIONS

L. monocytogenes, S. aureus, and methicillin-resistant Staphylococcus aureus (MRSA) were inhibited by different Arum extracts. The antibacterial activity of Arum hygrophilum Bioss against foodborne pathogens makes it safe to use as a natural food preservative, and as a source for sanitizers and antimicrobials. Further investigation is recommended to determine the cytotoxicity of the plant against additional cancer cell lines.

Ethyl methanesulphonate in a parenteral formulation of BMS-214662 mesylate, a selective farnesyltransferase inhibitor: formation and rate of hydrolysis

The objectives of the present study were to investigate the formation and rate of hydrolysis of ethyl methanesulphonate (EMS) in BMS-214662 mesylate drug substance and parenteral formulation by a gas chromatographic/mass spectrometric (GC/MS) method. EMS levels in the drug substance ranged between 0.3 microg/g and 0.8 microg/g. The parenteral formulation contains ethanol and the reaction between residual free methane sulphonic acid and ethanol may lead to the formation of EMS. Given that EMS is a potent mutagen, it is therefore of vital importance to eliminate or reduce the risk of human exposure. Data indicate no significant increase in the levels of EMS following storage of the drug product for 18 weeks at 25 degrees C or six weeks at 60 degrees C indicating that the potential reaction between ethanol and free methane sulphonic acid may not occur in the BMS-214662 formulation under the storage conditions evaluated and therefore causes no plausible safety concerns of EMS exposure in humans. Kinetic studies were conducted by spiking 200 ppb of EMS into water and the diluted and undiluted parenteral formulation. The rates of hydrolysis of EMS at 25 degrees C followed pseudo-first order kinetics and were determined to be 2.35 x 10(-4)min(-1), 67.4 x 10(-4)min(-1), and 1.32 x 10(-4)min(-1) in water, undiluted, and diluted drug product, respectively.

Impurities in a Lyophilized Formulation of BMS-204352: Identification and Role of Sanitizing Agents

The purpose of this study was to identify two impurities in the parenteral lyophilized formulation of BMS-204352, investigate the role of sanitizing agents as their potential source, evaluate their effect on drug product stability, and develop a strategy to prevent their contamination of the drug product. The two impurities were identified as o-phenylphenol and 4-t-amylphenol based on liquid chromatography/mass spectroscopy (LC/MS) and chromatographic comparison to authentic samples. The LC/MS spectra of commercially available o-phenylphenol and 4-t-amylphenol showed identical patterns of fragmentation and the same retention times as the impurities identified in the BMS-204352 lyophilized product. Levels of these impurities were low and ranged between 0.2-0.3 microg/vial as determined by HPLC and using an authentic external reference standard. To confirm the hypothesis that the commercial sanitizing agents used in the sterile area were the source of these phenolic impurities, several product samples were spiked with the sanitizing agents. Both o-phenylphenol and 4-t-amylphenol were detected in the spiked samples. Further investigation revealed that o-phenylphenol and 4-t-amylphenol are active ingredients of these commercial sanitizing agents. Drug product samples containing the phenolic impurities showed no potency loss following storage at 30, 50, and 70 degrees C indicating these impurities had no adverse effect on product stability. These studies suggest that sanitizing agents used in the sterile area, although may be present at trace levels below typical cleaning procedure detection methods, need to be properly controlled and closely monitored during the manufacturing of injectable products, particularly highly potent drugs. Sanitizing agents, even though not used on product contact surfaces, may potentially contaminate a product through vapor transfer in an open environment.

Effect of Cations and Anions on Glass Transition Temperatures in Excipient Solutions

The purpose of this study was to investigate the effects of cations and anions of various electrolytes on the glass transition temperature (Tg') of frozen solutions of excipients commonly used in freeze-drying. The effect of electrolyte concentration on freezable water content was also investigated by measuring the enthalpy of melting (DeltaH) using Differential Scanning Calorimetry (DSC). Cations and anions induce changes in Tg' of frozen solutions of commonly used parenteral excipients. These changes are dependent on the properties of the excipients used. Tg' values of 5% w/v solutions of maltose, trehalose, sucrose, dextran 40, and polyvinylpyrrolidone (PVP, 17K) were determined as a function of sodium chloride (NaCl) or potassium chloride (KCl) concentrations. In general, a significant decrease in Tg' was observed as a function of increasing the electrolyte concentration. For the disaccharide solutions, the decrease in Tg' due to the addition of NaCl or KCl was similar in magnitude, indicating that changing the cation from K+ to Na+ had no effect on Tg'. However, the decrease in Tg' for the PVP solution due to the addition of KCl was greater than that observed by the addition of NaCl . The differences in the electrolyte-induced changes on Tg' between the disaccharides and PVP may be potentially attributed to the formation of complexes between the cations and the properly oriented hydroxyl groups in the sugars leaving the anions (Cl- ions) to exert their effect on Tg'. While zero cation effect would be consistent with these results for the disaccharides, these results do not mean that the cation effects are zero; they only mean that the cation effects are the same. For the PVP solution, K+ and Na+ ions are not engaged in complex formation with PVP due to the lack of hydroxyl groups. We hypothesize that the structure-breaking K+ ions increase the fluidity of water and exert a greater plasticizing effect on Tg', leading to a more significant decrease in Tg' than the structure-making Na+ ions, which increase the viscosity of water. The decrease in Tg' of frozen solutions of pharmaceutical excipients caused by the addition of electrolytes may be primarily attributed to an increase in the unfrozen plasticizing water surrounding the excipient molecules. Formulation scientists should evaluate the use of electrolytes in the formulation development of lyophilized products containing commonly used excipients. Electrolytes are often needed as stabilizers for protein formulations; however, their selection and use should be properly evaluated. Because electrolytes cause a decrease in Tg' as a function of electrolyte concentration, it is recommended that the minimum electrolyte concentration needed to maintain product stability should be used to minimize the effect of the electrolyte on lowering the Tg'.

Degradation of a Lyophilized Formulation of BMS-204352: Identification of Degradants and Role of Elastomeric Closures

The purpose of this study was to identify two degradation products formed in the parenteral lyophilized formulation of BMS-204352, investigate the possible role of elastomeric closures in their formation, and develop a strategy to minimize/control their formation. The first degradant was identified as the hydroxymethyl derivative (formaldehyde adduct, BMS-215842) of the drug substance formed by the reaction of BMS-204352 with formaldehyde. Structure confirmation was based on liquid chromatography/mass spectroscopy (LC/MS), nuclear magnetic resonance (NMR), and chromatographic comparison to an authentic sample of the hydroxymethyl degradation product, BMS-215842. To confirm the hypothesis that formaldehyde originated from the rubber closure, migrated into the product, and reacted with BMS-204352 drug substance to form the hydroxymethyl degradant, lyophilized drug product was manufactured, the vials were stoppered with two different rubber closure formulations, and its stability was monitored. The formaldehyde adduct degradant was observed only in the drug product vials stoppered with one of the rubber closures that was evaluated. Although formaldehyde has not been detected historically as leachable and is not an added ingredient in the rubber formulation, information obtained from the stopper manufacturer indicated that the reinforcing agent used in the stopper formulation may be a potential source of formaldehyde. The second degradant was identified as the desfluoro hydroxy analog (BMS-188929) based on LC/MS, NMR, and chromatographic comparison to an authentic sample of the desfluoro hydroxy degradation product.

Influence of formaldehyde impurity in polysorbate 80 and PEG-300 on the stability of a parenteral formulation of BMS-204352: identification and control of the degradation product

The purpose of this study was to identify a degradation product formed in the clinical parenteral formulation of BMS-204352, investigate the role of excipients in its formation, and develop a strategy to minimize/control its formation. The degradant was identified as the hydroxy methyl derivative (formaldehyde adduct, BMS-215842) of the drug substance based upon liquid chromatography/mass spectroscopy (LC/MS), liquid chromatography/mass spectroscopy/mass spectroscopy (LC/MS/MS), nuclear magnetic resonance (NMR), and chromatographic comparison to an authentic sample of hydroxymethyl degradation product, BMS-215842. An assay method for the detection of formaldehyde based on HPLC quantitation of formaldehyde dinitrophenylhydrazone was developed to quantitate its levels in various Polysorbate 80 and PEG 300 excipient lots. A direct relationship between the levels of formaldehyde in the excipients and the formation of the hydroxymethyl degradant was found. To confirm the hypothesis that the formaldehyde impurity in these two excipients contributed to the formation of the hydroxymethyl degradant, several clinical formulation lots were spiked with formaldehyde equivalent to 1, 10, and 100 mg/g of BMS-204352. A correlation was found between the formaldehyde level and the quantity of the hydroxymethyl degradant formed upon storage at 5 and 25 degrees C. From these experiments, a limit test on the formaldehyde content in polysorbate 80 and PEG 300 can be set as part of a strategy to limit the formation of the degradation product.

Stability of batanopride hydrochloride in aqueous solutions

The degradation of batanopride hydrochloride, an investigational antiemetic drug, was studied in aqueous buffer solutions (pH 2-10; ionic strength, 0.5; 56 degrees C) in an attempt to improve drug stability for parenteral administration. Degradation occurs by two different mechanisms depending on the pH of the solution. In acidic media (pH 2-6), the predominant reaction was intramolecular cyclization followed by dehydration to form a 2,3-dimethylbenzofuran. There was no kinetic or analytical (high-performance liquid chromatography) evidence for the formation of an intermediate; therefore, the rate of dehydration must have been very rapid compared with the rate of cyclization. In alkaline media (pH 8-10), the primary route of degradation was cleavage of the C-O alkyl ether bond. In the intermediate pH range (pH 6-8), both reactions contributed to the overall degradation. Both degradation reactions followed apparent first-order kinetics. The pH-rate profile suggests that batanopride hydrochloride attains its optimal stability at pH 4.5-5.5. Citrate buffer was catalytic at pH 3 and 5, and phosphate buffer was catalytic at pH 8. No catalytic effect was observed for the borate buffer at pH 9-10.

Effects of structural variations on the rates of enzymatic and nonenzymatic hydrolysis of carbonate and carbamate esters

The effect of structural variations on the rates of elastase-catalyzed hydrolysis of model carbonate and carbamate esters was studied using HPLC. It is shown that branching in the immediate vicinity of the carbonate or carbamate functionally results in decreased hydrolysis rates. Whereas aryl carbonates act as substrates for elastase, p-nitrophenyl butyl carbamate inhibits the enzyme. A novel method was developed for the entrapment and quantitation of 14CO2 produced upon hydrolysis of carbonyl-14C-labeled carbonate esters. This technique could be useful in studying the mechanism of enzymatic hydrolysis of this type of compound and has the potential of being adapted as a convenient method in the assessment of estrolytic activity of tissue homogenates.