The new preservative-free ophthalmic formulation of bilastine 0.6% preserves the ocular surface epithelial integrity in a comparative in vitro study

Allergic conjunctivitis (AC) is the most common form of allergic eye disease and an increasingly prevalent condition. Topical eye drop treatments are the usual approach for managing AC, although their impact on the ocular surface is not frequently investigated. The aim of this study was to perform a comparative physicochemical characterization, and in vitro biological evaluations in primary conjunctival and corneal epithelial cells of the new multidose preservative-free bilastine 0.6% and main commercially available eye drops. MTT assay was used to measure cell viability; oxidative stress was analyzed with a ROS-sensitive probe; and apoptosis was evaluated monitoring caspase 3/7 activation. Differences in pH value, osmolarity, viscosity and phosphate levels were identified. Among all formulations, bilastine exhibited pH, osmolarity and viscosity values closer to tear film (7.4, 300 mOsm/l and ~ 1.5-10 mPa·s, respectively), and was the only phosphates-free solution. Single-dose ketotifen did not induce ROS production, and single-dose azelastine and bilastine only induced a mild increase. Bilastine and single-dose ketotifen and azelastine showed high survival rates attributable to the absence of preservative in its formulation, not inducing caspase-3/7-mediated apoptosis after 24 h. Our findings support the use of the new bilastine 0.6% for treating patients with AC to preserve and maintain the integrity of the ocular surface.

Antibacterial and antibiofilm effects of Camellia oleifera seed dreg extract and its application in cosmetics

BACKGROUND

Cosmetic care products contain a high proportion of water and nutrients. Therefore, preventing bacterial growth is an important issue to ensure product quality and safety. The application of antibacterial natural ingredients derived from plants is considered to have the potential to maintain product quality and reduce the use of chemicals in formulations. Additionally, chemically synthesized antiseptic and antibacterial agents are widely used in the industry at present. However, some preservative ingredients have been reported that may cause skin irritation, redness, allergies, and even dermatitis.

AIMS

This study aimed to prepare extract from Camellia oleifera tea seed dregs (CTSD), investigate the antibacterial effects on two pathogenic bacteria and evaluate the product preservative ability.

METHODS

Ethanol extraction was prepared and subjected to characterize their triterpenoid contents. The minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and minimum biofilm eradication concentration (MBEC) were determined for Pseudomonas aeruginosa and Staphylococcus aureus. The product's stability and preservative qualities, along with its ability to scavenge free radicals through antioxidant activity, were also assessed.

RESULTS

The gram-positive S. aureus showed greater susceptibility to the treatment. In additional, CTSD possessed significant free radical scavenging activity in vitro and cultured normal human skin fibroblast CCD-966SK cells under nontoxic concentration. The challenge test and accelerated storage test confirmed the CTSD containing formulated emulsion is eligible for commercialization.

CONCLUSIONS

CTSD has the potential to be developed as an alternative agent to control microbial biofilm formation, or can be used as an adjuvant compound for infectious disease control.

Machine learning assisted rational design of antimicrobial peptides based on human endogenous proteins and their applications for cosmetic preservative system optimization

Preservatives are essential components in cosmetic products, but their safety issues have attracted widespread attention. There is an urgent need for safe and effective alternatives. Antimicrobial peptides (AMPs) are part of the innate immune system and have potent antimicrobial properties. Using machine learning-assisted rational design, we obtained a novel antibacterial peptide, IK-16-1, with significant antibacterial activity and maintaining safety based on β-defensins. IK-16-1 has broad-spectrum antimicrobial properties against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans, and has no haemolytic activity. The use of IK-16-1 holds promise in the cosmetics industry, since it can serve as a preservative synergist to reduce the amount of other preservatives in cosmetics. This study verified the feasibility of combining computational design with artificial intelligence prediction to design AMPs, achieving rapid screening and reducing development costs.

Comparing the effect of benzalkonium chloride-preserved, polyquad-preserved, and preservative-free prostaglandin analogue eye drops on cultured human conjunctival goblet cells

PURPOSE

To investigate the effect of benzalkonium chloride (BAK)-preserved latanoprost and bimatoprost, polyquad (PQ)-preserved travoprost, and preservative-free (PF) latanoprost and tafluprost, all prostaglandin analogues (PGAs), on human conjunctival goblet cell (GC) survival. Furthermore, to investigate the effect of BAK-preserved and PF latanoprost on the cytokine secretion from GC.

METHODS

Primary human conjunctival GCs were cultivated from donor tissue. Lactate dehydrogenase (LDH) and tetrazolium dye colorimetric (MTT) assays were used for the assessment of GC survival. A cytometric bead array was employed for measuring secretion of interleukin (IL)-6 and IL-8 from GC.

RESULTS

BAK-preserved latanoprost and bimatoprost reduced cell survival by 28% (p = 0.0133) and 20% (p = 0.0208), respectively, in the LDH assay compared to a negative control. BAK-preserved latanoprost reduced cell proliferation by 54% (p = 0.003), BAK-preserved bimatoprost by 45% (p = 0.006), PQ-preserved travoprost by 16% (p = 0.0041), and PF latanoprost by 19% (p = 0.0001), in the MTT assay compared to a negative control. Only PF tafluprost did not affect the GCs in either assay. BAK-preserved latanoprost caused an increase in the secretion of pro-inflammatory IL-6 and IL-8 (p = 0.0001 and p = 0.0019, respectively) compared to a negative control, which PF latanoprost did not.

CONCLUSION

BAK-preserved PGA eye drops were more cytotoxic to GCs than PQ-preserved and PF PGA eye drops. BAK-preserved latanoprost induced an inflammatory response in GC. Treatment with PF and PQ-preserved PGA eye drops could mean better tolerability and adherence in glaucoma patients compared to treatment with BAK-preserved PGA eye drops.

Solvent-free enzymatic synthesis and evaluation of vanillyl propionate as an effective and biocompatible preservative

Preservatives are chemicals added to protect products against microbial spoilage, and thus are indispensable for pharmaceuticals, cosmetics, and foods. Due to growing concerns about human health and environments in conventional chemical preservatives, many companies have been seeking safe and effective alternatives that can be produced through environment-friendly processes. In this work, in order to develop effective and safe preservatives from plants, we attempt solvent-free lipase-catalyzed transesterification of vanillyl alcohol with ethyl propionate for the first time. The reaction product, vanillyl propionate was efficiently obtained in a high yield. Unlike vanillyl alcohol and ethyl propionate, vanillyl propionate showed antimicrobial activity. The minimal inhibitory concentration test showed that it exhibited high and broad antimicrobial activity against all the tested microorganisms (Gram-negative and Gram-positive bacteria, yeasts, and molds), which was overall comparable to that of propyl paraben, which is one of the most effective preservatives. It was also found to have even higher antioxidant capacity and biocompatibility with human cells than propyl paraben. Vanillyl propionate, which is a plant-based preservative produced through a green bioprocess, is expected to be successfully applied to various industries thanks to its high antimicrobial and antioxidant effect, and high biocompatibility.

Cytotoxicity, Mitochondrial Functionality, and Redox Status of Human Conjunctival Cells after Short and Chronic Exposure to Preservative-Free Bimatoprost 0.03% and 0.01%: An In Vitro Comparative Study

Prostaglandin analogues (PGAs), including bimatoprost (BIM), are generally the first-line therapy for glaucoma due to their greater efficacy, safety, and convenience of use. Commercial solutions of preservative-free BIM (BIM 0.03% and 0.01%) are already available, although their topical application may result in ocular discomfort. This study aimed to evaluate the in vitro effects of preservative-free BIM 0.03% vs. 0.01% in the human conjunctival epithelial (HCE) cell line. Our results showed that long-term exposure to BIM 0.03% ensues a significant decrease in cell proliferation and viability. Furthermore, these events were associated with cell cycle arrest, apoptosis, and alterations of ΔΨ_m. BIM 0.01% does not exhibit cytotoxicity, and no negative influence on conjunctival cell growth and viability or mitochondrial activity has been observed. Short-time exposure also demonstrates the ability of BIM 0.03% to trigger reactive oxygen species (ROS) production and mitochondrial hyperpolarisation. An in silico drug network interaction was also performed to explore known and predicted interactions of BIM with proteins potentially involved in mitochondrial membrane potential dissipation. Our findings overall strongly reveal better cellular tolerability of BIM 0.01% vs. BIM 0.03% in HCE cells.

Rapid assessment and prediction of the efficiency of two preservatives against S. aureus in cosmetic products using High Content Screening-Confocal Laser Scanning Microscopy

Most cosmetic products are susceptible to microbiological spoilage due to contaminations that could happen during fabrication or by consumer’s repetitive manipulation. The composition of cosmetic products must guarantee efficient bacterial inactivation all along with the product shelf life, which is usually assessed by challenge-tests. A challenge-test consists in inoculating specific bacteria, i.e. Staphylococcus aureus, in the formula and then investigating the bacterial log reduction over time. The main limitation of this method is relative to the time-consuming protocol, where 30 days are needed to obtain results. In this study, we have proposed a rapid alternative method coupling High Content Screening—Confocal Laser Scanning Microscopy (HCS-CLSM), image analysis and modeling. It consists in acquiring real-time S. aureus inactivation kinetics on short-time periods (typically 4h) and in predicting the efficiency of preservatives on longer scale periods (up to 7 days). The action of two preservatives, chlorphenesin and benzyl alcohol, was evaluated against S. aureus at several concentrations in a cosmetic matrix. From these datasets, we compared two secondary models to determine the logarithm reduction time (Dc) for each preservative concentration. Afterwards, we used two primary inactivation models to predict log reductions for up to 7 days and we compared them to observed log reductions. The IQ model better fits datasets and the Q value gives information about the matrix level of interference.

Phycocosmetics and Other Marine Cosmetics, Specific Cosmetics Formulated Using Marine Resources

Marine resources exist in vast numbers and show enormous diversity. As a result, there are likely many possible applications for marine molecules of interest in the cosmetic industry, whether as excipients or additives, but especially as active substances. It is possible to obtain extracts from active substances; for example, quite a few algae species can be used in moisturizing or anti-ageing products. In the field of topical photoprotection, mycosporine-like amino acids and gadusol are important lines of enquiry that should not be overlooked. In the field of additives, the demonstration that certain seaweed (algae) extracts have antimicrobial properties suggests that they could provide alternatives to currently authorized preservatives. These promising leads must be explored, but it should be kept in mind that it is a long process to bring ingredients to market that are both effective and safe to use.

Betanin, a Natural Food Additive: Stability, Bioavailability, Antioxidant and Preservative Ability Assessments

Betanin is the only betalain approved for use in food and pharmaceutical products as a natural red colorant. However, the antioxidant power and health-promoting properties of this pigment have been disregarded, perhaps due to the difficulty in obtaining a stable chemical compound, which impairs its absorption and metabolism evaluation. Herein, betanin was purified by semi-preparative HPLC-LC/MS and identified by LC-ESI(+)-MS/MS as the pseudomolecular ion m/z 551.16. Betanin showed significant stability up to -30 °C and mild stability at chilling temperature. The stability and antioxidant ability of this compound were assessed during a human digestion simulation and ex vivo colon fermentation. Half of the betanin amount was recovered in the small intestine digestive fluid and no traces were found after colon fermentation. Betanin high antioxidant ability was retained even after simulated small intestine digestion. Betanin, besides displaying an inherent colorant capacity, was equally effective as a natural antioxidant displaying peroxy-radical scavenger ability in pork meat. Betanin should be considered a multi-functional molecule able to confer an attractive color to frozen or refrigerated foods, but with the capacity to avoid lipid oxidation, thereby preserving food quality. Long-term supplementation by beetroot, a rich source of betanin, should be stimulated to protect organisms against oxidative stress.

Antimicrobial susceptibility profile, Adherence and invasion to mammalian cells of Brucellamelitensis isolates

Susceptibilities of 66 Brucella isolates were tested in vitro. All isolates were susceptible to doxycycline, gentamic in and streptomycin. In addition, propyl paraben, cresol and benzalkoniumchloride were found to be the most powerful tested preservative, disinfectant and antiseptic, respectively. All isolates adhered to and invaded into Vero cells by variable degrees. Adherence and invasion of most isolates were significantly reduced by: (1) pretreatment of test isolates with trypsin and sodium metaperiodate; (2) pretreatment of Vero cells with lipase, neuraminidase and sodium metaperiodate; (3) Presence of Ca⁺⁺, Mg⁺⁺ and 200mM mannose in the assay medium and (4) growth of test isolates in half MICs of different antimicrobial agents. On the other hand, pretreatment of Vero cells with trypsin increased the adherence and invasion of most test isolates. No significant change in adhesion and invasion by changing the temperature from 27°C to 42°Cor the pH from 6 to 8. Log phase cultures showed higher adherence and invasion than stationary phase cultures.

Preservative effect of Chinese cabbage (Brassica rapa subsp. pekinensis) extract on their molecular docking, antioxidant and antimicrobial properties

This study aimed at investigating the antimicrobial activity of different solvent extracts of Chinese cabbage Brassica rapa subsp. pekinensis (BRARP) and their antioxidant and cytotoxicity properties. Of the different solvents extracts, the chloroform extracts (CE) were significantly inhibited the bacterial pathogens at minimum inhibitory concentration (MIC) of 16.5 mg.mL^-1. Biochemical analysis revealed that total phenol (62.6 ± 0.05 mg GAE.g^-1) and flavonoids (27.6 ± 0.04 mg QE.g^-1) were higher in the extracts of BRARP, which resulted in enhanced antioxidant activity in CE. A total of eight dominant compounds were detected in the potent antimicrobial extract from BRARP based on GC-MS analysis. The molecular interactions study revealed that, among the screened compounds the 1,2-benzenedicarboxylic acid and 2,3-dicyanopropionamide interacted with the active site of pathogenicity and survival related protein with lipopolysaccharide (LpxC) with higer binding energy. This work concluded that the 1, 2-Benzenedicarboxylic acid and 2, 3-Dicyanopropionamide from BRARP was reported to be good non-cytotoxic and antioxidant antimicrobials against bacterial pathogens.

The consistent differential expression of genetic pathways following exposure of an industrial Pseudomonas aeruginosa strain to preservatives and a laundry detergent formulation

Pseudomonas aeruginosa is a common contaminant associated with product recalls in the home and personal care industry. Preservation systems are used to prevent spoilage and protect consumers, but greater knowledge is needed of preservative resistance mechanisms used by P. aeruginosa contaminants. We aimed to identify genetic pathways associated with preservative exposure by using an industrial P. aeruginosa strain and implementing RNA-Seq to understand gene expression changes in response to industry relevant conditions. The consistent differential expression of five genetic pathways during exposure to multiple industrial growth conditions associated with benzisothiazolone (BIT) and phenoxyethanol (POE) preservatives, and a laundry detergent (LD) formulation, was observed. A MexPQ-OpmE Resistance Nodulation Division efflux pump system was commonly upregulated in response to POE, a combination of BIT and POE, and LD together with BIT. In response to all industry conditions, a putative sialic acid transporter and isoprenoid biosynthesis gnyRDBHAL operon demonstrated consistent upregulation. Two operons phnBA and pqsEDCBA involved in Pseudomonas quinolone signaling production and quorum-sensing were also consistently downregulated during exposure to all the industry conditions. The ability to identify consistently differentially expressed genetic pathways in P. aeruginosa can inform the development of future targeted preservation systems that maintain product safety and minimise resistance development.

Antimicrobial Ingredients as Preservative Booster and Components of Self-Preserving Cosmetic Products

This review reports cosmetic ingredients with antimicrobial activity including synthetic and natural (plant and microbial) origin as alternative for preservatives used in cosmetics as well described mechanism of their action.

Use of Preservative Agents and Antibiotics for Increased Poliovirus Survival on Positively Charged Filters

Environmental surveillance of poliovirus (PV) and other non-enveloped viruses can help identify silent circulation and is necessary to certify eradication. The bag-mediated filtration system is an efficient method to filter large volumes of environmental waters at field sites for monitoring the presence of viruses. As filters may require long transit times to off-site laboratories for processing, viral inactivation or overgrowth of bacteria and fungi can interfere with virus detection and quantification (Miki and Jacquet in Aquatic Microb Ecol 51(2):195-208, 2008). To evaluate virus survival over time on ViroCap^™ filters, the filters were seeded with PV type 1 (PV1) and/or MS2 and then dosed with preservatives or antibiotics prior to storage and elution. These filters were stored at various temperatures and time periods, and then eluted for PV1 and MS2 recovery quantification. Filters dosed with the preservative combination of 2% sodium benzoate and 0.2% calcium propionate had increased virus survival over time when stored at 25 °C, compared to samples stored at 25 °C with no preservatives. While elution within 24 h of filtration is recommended, if storage or shipping is required then this preservative mixture can help preserve sample integrity. Addition of an antibiotic cocktail containing cephapirin, gentamicin, and Proclin^™ 300 increased recovery after storage at 4 and 25 °C, when compared to storage with no antibiotics. The antibiotic cocktail can aid sample preservation if access to appropriate antibiotics storage is available and sample cold chain is unreliable. This study demonstrated that the use of preservatives or antibiotics is a simple, cost-effective method to improve virus detection from ViroCap cartridge filters over time.

Antiglaucomatous treatments and ocular surface

BACKGROUND

the antiglaucomatous treatments interact with the ocular surface and can induce its alteration which may affect the therapeutic results Aim : to describe the interactions between the ocular surface and anti-glaucoma medications and to propose practical attitudes to prevent and manage this issue.

METHODS

a retrospective study about 100 patients with a primary opened angle glaucoma treated with anti-glaucomatous drops containing preservatives. We performed an exhaustive examination of the ocular surface with fluorescein instillation to search superficial punctuate keratitis and to evaluate the break up time. All patients had a Schirmer test I.

RESULTS

our patients were under monotherapy in 46% ,two medications in 36%, three medications in 11% and four medications in 7% .Beta-blockers were statistically related to the conjunctival hyperaemia (p = 0.014), BUT alteration (p = 0.001) and Schirmer test ≤ 5 mm (p = 0.0001). Prostaglandin analogues were statistically related to a Schirmer test ≤ 5 mm (p = 0.02). The use of more than two anti-glaucomatous medications was linked to the severity of the clinical signs.

CONCLUSIONS

anti glaucoma drops affect the ocular surface through several mechanisms: allergic reaction, direct and indirect toxicity of the active agents as well as their preservatives. The risk is increased by the prior ocular surface abnormalities in these patients. This disease influences the quality of life and leads to poor adherence to treatment.

Development of topical ophthalmic In Situ gel-forming estradiol delivery system intended for the prevention of age-related cataracts

The goal of this study was to develop and characterize an ion-activated in situ gel-forming estradiol (E2) solution eye drops intended for the prevention of age-related cataracts. Accordingly, in situ gelling eye drops were made using gellan gum as an ion-activated gel-forming polymer, polysorbate-80 as drug solubilizing agent, mannitol as tonicity agent, and combination of potassium sorbate and edetate disodium dihydrate (EDTA) as preservatives. The formulations were tested for the following characteristics: pH, clarity, osmolality, antimicrobial efficacy, rheological behavior, and in vitro drug release. Stability of the formulation was also monitored for 6 months at multiple storage conditions per ICH Q1A (R2) guidelines. The solution eye drops resulted in an in-situ phase change to gel-state when mixed with simulated tear fluid (STF). The gel structure formation was confirmed by viscoelastic measurements. Drug release from the gel followed non-fickian mechanism with 80% of drug released in 8 hr. The formulations were found to be clear, isotonic with suitable pH and viscoelastic behavior and stable at accelerated and long-term storage conditions for 6 months. In vitro results suggest that the developed formulation is suitable for further investigation in animal models to elucidate the ability of estrogen to prevent and delay cataracts.

Poor Preservation Efficacy Versus Quality and Safety of Pediatric Extemporaneous Liquids

Background:

Most medicines are available only as solid, adult-strength dosage forms from which oral extemporaneous liquids are often prepared for children. There are few comprehensive reference lists for the preparation of pediatric extemporaneous formulations. Some pediatric reformulations are made by diluting the suspending vehicle, and a shelf life of up to 3 months can be used without documented microbial stability. Although most commercially available ready-to-use vehicles are supplied as preserved formulations, it is still common practice in many European dispensaries to prepare and dilute these vehicles as required for specific prescriptions.

Objective:

To determine what influence dilution of vehicles has on the preservation efficiency of extemporaneous formulations.

Methods:

Suspending vehicles were made by diluting methylcellulose 1% and simple syrup, BP (British Pharmacopoeia) in ratios of 1:1 and 1:4. The efficacy of antimicrobial preservation was tested according to the 2007 standards required by the BP.

Results:

Dilution in ratios greater than 1:1 failed the BP 2007 criteria. Such dilution represents a potential biohazard, especially to premature, newborn, or immunocompromised children, exposing them not only to possible organoleptic changes of the preparation, but also to ingestion of either dangerous numbers of microorganisms or medicines that may have undergone biotransformation, rendering them inactive or toxic.

Conclusions:

Significant concerns have been raised regarding the quality of extemporaneous preparations. We call for further research in this neglected area to address issues of antimicrobial preservation, including revision of existing quality assurance monographs. Moreover, these monographs should take into account testing that simulates multiple dosing from a single storage container during the intended in-use shelf life of multidose extemporaneous preparations.

Formulation and Stability of Solutions

Ready-to-use solutions are the most preferable and most common dosage forms for injectable and topical ophthalmic products. Drugs formulated as solution almost always have chemical and physical stability challenges as well as solubility limitations and the need to prevent inadvertent microbial contamination issues. The first in this series of articles took us through a discussion of optimizing the physical stability of solutions. This article concludes this series of articles with a discussion on foreign particles, protein aggregation, and immunogenicity; optimizing microbiological activity; and osmolality (tonicity) agents, and discusses how these challenges and issues are addressed.

[Preservation of live eggs of Schistosoma japonicum]

OBJECTIVE

To observe the preservation time and activity of miracidium hatching from schistosome eggs preserved in different solutions, so as to obtain the optimal preservation conditions and then provide quality control products for field application.

METHODS

The rectum stool of rabbits infected with Schistosoma japonicum was collected and the coarse fecal residue was removed with a series of sample sieves of 80, 100, 160 and 200 meshes respectively, and then the schistosome eggs were concentrated with the sample sieve of 260 meshes. The concentrated eggs were preserved in 0.9% sodium chloride solution, 1.2% sodium chloride solution, phosphate buffered saline solution (PBS, PH 7.2), 1.0% sucrose solution, and Mili-Q water, respectively, and then were conserved in a 4 °C refrigerator and 15 °C constant temperature incubator, respectively. The preserved eggs were hatched in different time (7-day interval) , the vitality and quantity of the miracidia were observed, and the hatching rates were calculated.

RESULTS

Under the condition of 4 °C, the hatching rates of eggs dropped to 0 in 1.0% sucrose solution and 1.2% sodium chloride solution at the 49th and 126th day, respectively, and the hatching rates of eggs in the 0.9% sodium chloride solution and PBS solution dropped to 10% at the 112th day, and the activity of miracidium was weakened since 140th. In the Mili-Q water, the hatching rate dropped less than 10% at the 196th day and the activity of miracidia was weakened since the 280th day. Under the condition of 15 °C, the hatching rate of eggs in different solutions gradually dropped to 0 from the 49th day to 105th day.

CONCLUSION

The eggs preserved in Mili-Q water at the temperature of 4 °C can be used as the positive reference for hatching tests within 196 days.

Antibacterial Effects of Cinnamon: From Farm to Food, Cosmetic and Pharmaceutical Industries

Herbs and spices have been used since ancient times, because of their antimicrobial properties increasing the safety and shelf life of food products by acting against foodborne pathogens and spoilage bacteria. Plants have historically been used in traditional medicine as sources of natural antimicrobial substances for the treatment of infectious disease. Therefore, much attention has been paid to medicinal plants as a source of alternative antimicrobial strategies. Moreover, due to the growing demand for preservative-free cosmetics, herbal extracts with antimicrobial activity have recently been used in the cosmetic industry to reduce the risk of allergies connected to the presence of methylparabens. Some species belonging to the genus Cinnamomum, commonly used as spices, contain many antibacterial compounds. This paper reviews the literature published over the last five years regarding the antibacterial effects of cinnamon. In addition, a brief summary of the history, traditional uses, phytochemical constituents, and clinical impact of cinnamon is provided.

Microbial spoilage, instability risk of antacid suspension in the presence of commonly used preservative system

Manifestation of microbial spoilage of any product by bacteria and to assess the effectiveness of the anti-microbial preservatives (parabens) used for the prevention and stability purpose. The aim of the present work is to study the effectiveness of preservatives used in the antacid suspensions and to analyze the effect of microbial growth on the quality of respective antacid suspensions. Samples of various antacid suspensions were randomly collected from local market and Government hospital pharmacies. Three different antacid formulations were prepared in the laboratory. All the formulations were preliminarily evaluated on the basis of organoleptic characteristics, pH, viscosity and assay. Efficacy of the preservative system in suspension formulation was determined by inoculating the samples in its final container, with specific strains of bacteria i.e. Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 9027 and Staphylococcus aureus ATCC 6538, taking samples from the inoculated preparation at specified intervals of time i.e. 0 time, 07 days, 14 days and 28 days, growing it on nutrient agar medium and colony forming units (CFUs) were scored by plate count. At the same time the samples were also subjected to qualitative and quantitative testing. The decrease in CFU and alteration in assay, pH and viscosity was observed in all the formulations except formulation M2 and F3 that showed stability throughout the study period.

[Antimicrobial Effects of Iodine-Polyvinyl Alcohol Ophthalmic and Eye Washing Solution (PA * IODO) with Special Reference to its Temperature, Concentration and Time and its Preservation Stability]

PURPOSE

Temperature, concentration and time are the three factors that affect the inactivation capacity of iodine antiseptics. We investigated the effect of these factors on the microbe inactivation of Iodine-Polyvinyl Alcohol ophthalmic and eye washing solution (PA * IODO), and also investigated the preservation conditions on stability of the inactivation activity of the PA * IODO.

METHODS

Test microbes were mixed with PA * IODO, varying the three factors. The live microbes were counted after each reaction. The effects of plugging and preservation temperature were investigated to determine the preserving stability.

RESULTS

The inactivation capacity of PA * IODO tended to decrease in almost all microbes tested at 4 degrees C. Twenty times or less diluted PA * IODO killed almost all microbes completely. The time effect was more marked in viruses. Plugging and low-temperature made iodine concentration in diluted PA * IODO remain relatively high.

CONCLUSIONS

The concentration of PA * IODO affected the inactivation ability more than the temperature and time, although all the three factors correlated positively to the inactivation. For preservation the diluted PA * IODO needed plugging and low temperature.

Examination of the safety of pediatric vaccine schedules in a non-human primate model: assessments of neurodevelopment, learning, and social behavior

BACKGROUND

In the 1990s, the mercury-based preservative thimerosal was used in most pediatric vaccines. Although there are currently only two thimerosal-containing vaccines (TCVs) recommended for pediatric use, parental perceptions that vaccines pose safety concerns are affecting vaccination rates, particularly in light of the much expanded and more complex schedule in place today.

OBJECTIVES

The objective of this study was to examine the safety of pediatric vaccine schedules in a non-human primate model.

METHODS

We administered vaccines to six groups of infant male rhesus macaques (n = 12-16/group) using a standardized thimerosal dose where appropriate. Study groups included the recommended 1990s Pediatric vaccine schedule, an accelerated 1990s Primate schedule with or without the measles-mumps-rubella (MMR) vaccine, the MMR vaccine only, and the expanded 2008 schedule. We administered saline injections to age-matched control animals (n = 16). Infant development was assessed from birth to 12 months of age by examining the acquisition of neonatal reflexes, the development of object concept permanence (OCP), computerized tests of discrimination learning, and infant social behavior. Data were analyzed using analysis of variance, multilevel modeling, and survival analyses, where appropriate.

RESULTS

We observed no group differences in the acquisition of OCP. During discrimination learning, animals receiving TCVs had improved performance on reversal testing, although some of these same animals showed poorer performance in subsequent learning-set testing. Analysis of social and nonsocial behaviors identified few instances of negative behaviors across the entire infancy period. Although some group differences in specific behaviors were reported at 2 months of age, by 12 months all infants, irrespective of vaccination status, had developed the typical repertoire of macaque behaviors.

CONCLUSIONS

This comprehensive 5-year case-control study, which closely examined the effects of pediatric vaccines on early primate development, provided no consistent evidence of neurodevelopmental deficits or aberrant behavior in vaccinated animals.

Antimicrobial preservatives induce aggregation of interferon alpha-2a: the order in which preservatives induce protein aggregation is independent of the protein

Antimicrobial preservatives (APs) are included in liquid multi-dose protein formulations to combat the growth of microbes and bacteria. These compounds have been shown to cause protein aggregation, which leads to serious immunogenic and toxic side-effects in patients. Our earlier work on a model protein cytochrome c (Cyt c) demonstrated that APs cause protein aggregation in a specific manner. The aim of this study is to validate the conclusions obtained from our model protein studies on a pharmaceutical protein. Interferon α-2a (IFNA2) is available as a therapeutic treatment for numerous immune-compromised disorders including leukemia and hepatitis C, and APs have been used in its multi-dose formulation. Similar to Cyt c, APs induced IFNA2 aggregation, demonstrated by the loss of soluble monomer and increase in solution turbidity. The extent of IFNA2 aggregation increased with the increase in AP concentration. IFNA2 aggregation also depended on the nature of AP, and followed the order m-cresol>phenol>benzyl alcohol>phenoxyethanol. This specific order exactly matched with that observed for the model protein Cyt c. These and previously published results on antibodies and other recombinant proteins suggest that the general mechanism by which APs induce protein aggregation may be independent of the protein.

[Tafluprost--a novel prostaglandin F2alpha analogue]

The review provides a brief history of the evolution of ophthalmic containers: from glass vials to plastic bottles with obligatory preservatives and, finally, to preservative-free polypropylene single-use single-dose tubes. A brief characteristic of benzalkonium chloride, the most commonly used preservative, including mechanisms of its antiseptic activity and ocular toxicity is given. The problem of ocular surface damage, especially in glaucoma patients, due to the long-term use of preserved eye drops, is discussed. Pharmacodynamics of tafluprost, the first commercially available preservative-free single-dose prostaglandin analogue, is described. Operating characteristics of experimental preclinical studies and the first three phases of clinical trials of tafluprost are provided. Post-approval studies of the comparative efficacy and tolerability of the new drug are analyzed and its prospects for clinical use are assessed.

Is bacteriostatic saline superior to normal saline as an echocardiographic contrast agent?

Objective data on the performance characteristics and physical properties of commercially available saline formulations [normal saline (NS) vs. bacteriostatic normal saline (bNS)] are sparse. This study sought to compare the in vitro physical properties and in vivo characteristics of two commonly employed echocardiographic saline contrast agents in an attempt to assess superiority. Nineteen patients undergoing transesophageal echocardiograms were each administered agitated regular NS and bNS injections in random order and in a blinded manner according to a standardized protocol. Video time-intensity (TI) curves were constructed from a representative region of interest, placed paraseptally within the right atrium, in the bicaval view. TI curves were analyzed for maximal plateau acoustic intensity (Vmax, dB) and dwell time (DT, s), defined as time duration between onset of Vmax and decay of video intensity below clinically useful levels, reflecting the duration of homogenous opacification of the right atrium. To further characterize the physical properties of the bubbles in vitro, fixed aliquots of similarly agitated saline were injected into a glass well slide-cover slip assembly and examined using an optical microscope to determine bubble diameter in microns (µm) and concentration [bubble count/high power field (hpf)]. A higher acoustic intensity (a less negative dB level), higher bubble concentration and longer DT were considered properties of a superior contrast agent. For statistical analysis, a paired t test was conducted to evaluate the differences in means of Vmax and DT. Compared to NS, bNS administration was associated with superior opacification (video intensity -8.69 ± 4.7 vs. -10.46 ± 4.1 dB, P = 0.002), longer DT (17.3 ± 6.1 vs. 10.2 ± 3.7 s) in vivo and smaller mean bubble size (43.4 vs. 58.6 μm) and higher bubble concentration (1,002 vs. 298 bubble/hpf) in vitro. bNS provides higher intensity and more sustained opacification of the right atrium compared to NS. Higher bubble concentration and stability appear to be additional desirable rheological characteristics favoring bNS as a contrast agent.

[Investigation of antimicrobial and antibiofilm effects of some preservatives used in drugs, cosmetics and food products]

Preservatives are added to food, drugs and other pharmaceutical products to avoid microbial contamination. For antimicrobial activity testing and preservative efficacy testing, vegetative forms of the standard test organisms are used. However, microbial biofilm formation may occur on living tissues, medical implants, industrial or drinking water pipes, natural aquatic systems, glass and plastic surfaces. In our study, it was aimed to determine the antimicrobial and antibiofilm effects of some preservatives used in drug, cosmetics and food products and to compare the minimum biofilm inhibitory concentration (MBIC) of microbial biofilm formed on glass surfaces which are commonly used in those areas and the minimum inhibitory concentration (MIC) values of the planktonic forms. In the study Pseudomonas aeruginosa ATCC 27853, Salmonella Thyphimurium SL1344, Staphylococcus aureus ATCC 6538, Staphylococcus epidermidis NCTC 11047, Enterococcus faecalis ATCC 29212 and Candida albicans ATCC 10231 were used as the standard strains; sodium nitrate, methylparaben, prophylparaben, potassium sorbate and sodium benzoate as the preservatives; ampicillin, vancomycin, gentamicin, ciprofloxacin, amphotericin B and itraconazole as the antimicrobial agents. MIC values were determined through the guidelines of CLSI M100-S18 and M27-A3 protocols. BioTimer method was used to determine the MBIC values. The value of "colony forming unit (CFU)/glass beads" was calculated using the graphics drawn by plotting the time of color change for phenol red or resazurin against log10CFU. All experiments were done with four media at different pH values namely pH: 7, pH: 6.5, pH: 6 and pH: 5.5. According to the results of tests on planktonic forms of the microorganisms, sodium benzoate was determined to be the most effective preservative against all the microorganisms tested except S.aureus and E.faecalis. The most effective preservative against S.aureus and E.faecalis was prophylparaben. Prophylparaben was also effective against S.epidermidis. However, in our study it was determined that preservatives were not effective against biofilm forms even if the inoculum was lower, equal to or higher than the inocula of the planktonic forms. The data obtained from this study indicated that preservatives used to prevent microbial contamination in pharmaceutical, cosmetic and food products, are not effective against biofilm forms of the microorganisms. This study is thought to be a guide for further studies to be held in the investigation of antimicrobial and antibiofilm effects of preservatives used in drugs, cosmetics and food industry.

A combination of grapefruit seed extract and concentrated cranberry juice as a potential antimicrobial preservative for the improvement of microbiological stability of hypromellose gel

Aqueous hypromellose gels are not microbiologically stable - they show signs of microorganism growth during storage. To extend the shelf-life of the gels, antimicrobial preservatives are needed. Some substances of plant origin are known for their antimicrobial properties, and thus they may be used as an alternative to synthetic preservatives. Therefore, the aim of this study was to evaluate the microbiological stability of aqueous hypromellose gel and the effectiveness of natural substances - grapefruit seed extract (GSE), concentrated cranberry juice, and a combination thereof - on the antimicrobial protection of the gel. The evaluation of the antimicrobial activity of GSE and cranberry juice showed that their antimicrobial effects differed. Both cranberry juice and GSE inhibited the growth of the standard gram-positive and gram-negative bacteria, but the effect of GSE was significantly stronger. Candida albicans was sensitive only to GSE. For this reason, in order to affect all the microorganisms studied, either a combination of 0.7% GSE and 10% cranberry juice, or 5% GSE alone may be used. The combination of GSE and cranberry juice was effective only in acidic medium (pH being 2.5-5), while the antimicrobial effect of GSE was not dependent on the pH value.

Antimicrobial Efficacy of Gatifloxacin and Moxifloxacin with and without Benzalkonium Chloride Compared with Ciprofloxacin and Levofloxacin Against Methicillin- ResistantStaphylococcus aureus

We compared the antimicrobial activity of gatifloxacin and moxifloxacin with and without benzalkonium chloride (BAK) against clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA). Minimum inhibitory concentrations (MICs) against clinical isolates of MRSA were evaluated. Approximately 10(5 )CFU/ml of methicillinresistant S. aureus was added to Mueller-Hinton broth containing two-fold concentration increments of drug. For the evaluation of gatifloxacin with BAK, 50 microg/ml of BAK were added to the first well of the plate with gatifloxacin or moxifloxacin and then serially diluted. The combination of gatifloxacin or moxifloxacin with BAK was more active than either fluoroquinolone without BAK. The MICs ranged from <or=0.008 microg/ml to 0.125 microg/ml for gatifloxacin plus BAK, from 0.063 microg/ml to (3)8 microg/ml with unpreserved gatifloxacin from <0.004 to 0.25 for moxifloxacin plus BAK, and from <or=0.016 microg/ml to 16.0 microg/ml with unpreserved moxifloxacin. The combinations of gatifloxacin or moxifloxacin and BAK were highly active against MRSA in vitro, providing MICs that were approximately 2- to 500-fold lower than the MICs provided by either gatifloxacin or moxifloxacin without BAK.

Comparative cross-sectional analysis of the effects of topical antiglaucoma drugs on the ocular surface

INTRODUCTION

The aim of this study was to comparatively analyze the effects of topical intraocular pressure (IOP)-lowering drugs on the ocular surface and to elucidate whether the main causative factor of toxicity is associated with benzalkonium chloride (BAK) or an active compound.

METHODS

The medical records of 300 eyes in 187 glaucoma patients that had instilled IOP-lowering drugs were cross-sectionally reviewed. Corneal epithelial punctuate erosion and tear break-up time (BUT) were quantitatively assessed. Durations of glaucoma, sums of concentrations of BAK in current medication (BAK(%sum)), and the presence of beta-blockers were investigated as risk factors (Institutional Review Board of Seoul National University Hospital, Seoul - IRB number: H-1007-103-324).

RESULTS

Age-adjusted BAK(%sum) was found to be significantly and positively correlated with corneal epithelial punctate erosion (P = 0.001, r = 0.208) and negatively correlated with BUT (P = 0.042, r = 0.131). BAK(%sum) adjusted corneal epithelial erosion was found to be significantly greater in beta-blocker containing eyedrop-instilled eyes (P = 0.016). No difference in ocular toxicity was found between carbonic anhydrase inhibitor and prostaglandin analog or between latanoprost- and travoprost-treated eyes.

CONCLUSION

Long-term treatment with BAK-containing antiglaucoma medication appears to be the main contributor to corneal toxicity and to do so in a dose-dependent manner. Formulations containing beta-blockers also appear to contribute to corneal toxicity.

Effect of antimicrobial preservatives on partial protein unfolding and aggregation

One-third of protein formulations are multi-dose. These require antimicrobial preservatives (APs); however, some APs have been shown to cause protein aggregation. Our previous work on a model protein cytochrome c indicated that partial protein unfolding, rather than complete unfolding, triggers aggregation. Here, we examined the relative strength of five commonly used APs on such unfolding and aggregation, and explored whether stabilizing the aggregation 'hot-spot' reduces such aggregation. All APs induced protein aggregation in the order m-cresol > phenol > benzyl alcohol > phenoxyethanol > chlorobutanol. All these enhanced the partial protein unfolding that includes a local region which was predicted to be the aggregation 'hot-spot'. The extent of destabilization correlated with the extent of aggregation. Further, we show that stabilizing the 'hot-spot' reduces aggregation induced by all five APs. These results indicate that m-cresol causes the most protein aggregation, whereas chlorobutanol causes the least protein aggregation. The same protein region acts as the 'hot-spot' for aggregation induced by different APs, implying that developing strategies to prevent protein aggregation induced by one AP will also work for others.

Chemical composition and antimicrobial activity of essential oils of Thymus algeriensis, Eucalyptus globulus and Rosmarinus officinalis from Morocco

BACKGROUND

The present study reports on the antimicrobial activity and chemical composition of the essential oils (EOs) of Thymus algeriensis, Eucalyptus globulus and Rosmarinus officinalis from Morocco.

RESULTS

The composition of these species was analysed by GC-MS, and 65 components were identified. Eucalyptus globulus EO showed a great similarity with EOs from other regions, with 1,8-cineole (79.85%) the major component. Also rich in this constituent was Rosmarinus officinalis (43.99%). However, the chemical profile of Thymus algeriensis was rather different, and for the first time such a high content of borneol (23.48%) has been described in this EO. The antimicrobial activity of these species has also been studied against seven pathogenic and spoiling bacteria of significant importance. According to the results, Thymus algeriensis showed the best bacteriostatic and bactericidal effect, followed by Eucalyptus globulus and Rosmarinus officinalis.

CONCLUSIONS

As far as we know this is the first time that minimum inhibitory and bactericidal concentration values have been reported for Eucalyptus globulus EO. Our data support the possible use of this EO as well as Thymus algeriensis EO, as potential natural agents in preservatives for food and pharmaceutical products.

Compatibility of insulin Lispro, Aspart, and Glulisine with the Solo MicroPump, a novel miniature insulin pump

BACKGROUND

This study compared the stability of commercially available, rapid-acting insulin in the novel tubeless, skin-adhering Solo insulin pump over 6 days at extreme environmental conditions.

METHODS

Forty-eight pumps for each tested analog were loaded with three different insulin lots and operated at 30 U/day (three sets of 12 pumps) and 15 U/day (one set of 12 pumps) with basal/bolus delivery patterns for 6 days under extreme climatic (37 degrees C, 40% relative humidity) and mechanical (35 strokes/min) stresses. The insulin solutions dispensed were sampled periodically and analyzed for potency, related substances, high molecular weight proteins (HMWP), and preservative content by high-performance liquid chromatography techniques. Biological activity (bioidentity) was demonstrated by an abrupt decrease in blood glucose in rabbits. Solutions were inspected for visual appearance and measured for pH levels.

RESULTS

During the 6-day sampling period, the potency of all insulin samples was maintained at 95.0-105.0% of the bulk solution concentration of the insulin vials. The levels of HMWP and related substances remained well below labeling limits. The preservative concentration decreased with time but remained bacteriostatic effective. Solutions maintained pH and clarity and were particulate free. The biological activity was verified.

CONCLUSIONS

Insulin analogs lispro, aspart, and glulisine maintained physical, chemical, and biological properties for 6 days when used in the Solo MicroPump device.

Inhibitory mechanism of novel inhibitors of UDP-N-acetylglucosamine enolpyruvyl transferase from Haemophilus influenzae

Bacterial UDP-N-acetylglucosamine enolpyruvyl transferase (MurA) catalyzes the transfer of enolpyruvate from phosphoenolphyruvate (PEP) to uridine diphospho-N-acetylglucosamine (UNAG), which is the first step of bacterial cell wall synthesis. We identified thimerosal, thiram, and ebselen as effective inhibitors of Heamophilus influenzae MurA by screening a chemical library that consisted of a wide range of bioactive compounds. When MurA was preincubated with these inhibitors, their 50% inhibitory concentrations (IC50s) were found to range from 0.1 to 0.7 microM. In particular, thimerosal suppressed the growth of several different Gram-negative bacteria such as Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium at a concentration range of 1-2 microg/ml. These inhibitors covalently modified the cysteine residue near the active site of MurA. This modification changed the open conformation of MurA to a more closed configuration, which may have prevented the necessary conformational change from occurring during the enzyme reaction.

Quantitative and conformational characterization of lysozyme deposited on balafilcon and etafilcon contact lens materials

PURPOSE

To determine whether differences in lysozyme deposition and/or activity exist on worn etafilcon and balafilcon contact lenses following care with a polyquaternium-based system (PQ) or a polyhexanide-based system (PHMB).

METHODS

Following acid-based deposit extraction, lysozyme concentration was determined via Western blotting and lysozyme activity was determined by a micrococcyl assay.

RESULTS

Lysozyme deposition on etafilcon lenses was greater following disinfection with the PHMB-based system (1551 +/- 371 micro g/lens vs 935 +/- 271 micro g/lens; p < 0.001). Deposition on balafilcon lenses was not influenced by the care regimen (10 +/- 3.5 micro g/lens vs 10 +/- 5 micro g/lens; p = 0.89). For both materials, the percentage of denatured lysozyme was greater when they were exposed to the PHMB-based system (28 vs 21%; p = 0.05 (etafilcon) and 57 vs 40%; p = 0.04 (balafilcon)).

CONCLUSIONS

The quantity and conformation of lysozyme deposited on hydrogel contact lens materials is significantly influenced by both lens material and care regimen.

In vitro effects of preserved or preservative-free antiglaucoma medications on human complement system

PURPOSE

Antiglaucoma drugs have been associated with conjunctival and trabecular inflammatory cell infiltrates. However, the underlying mechanisms are still poorly understood. The aim of this study was to assess the effects of antiglaucoma medications on the complement system, an early mediator of the inflammatory response.

METHODS

Human serum was first treated with a classical or alternative pathway activator (aggregated human IgG or zymosan, respectively) in the presence or the absence of preservative-free or benzalkonium (BAK)-preserved antiglaucoma drugs. CH50 assay was then performed to assess the functional activity of residual complement in treated serum.

RESULTS

In the absence of complement activator, the antiglaucoma drugs tested in this study were all devoid of intrinsic complement-activating potency. Preserved and preservative-free carteolol as well as preserved latanoprost did not worsen or prevent complement activation induced by zymosan or aggregated IgG. Unexpectedly, both preserved and unpreserved timolol and betaxolol significantly counteracted the effects of complement activators. Timolol prevented activation triggered by both IgG and zymosan to the same extent (24% to 29%), despite the presence of BAK in the preserved formulation. Betaxolol was twice as effective at preventing the effect of IgG (34% to 37%) than that of zymosan (14%), regardless of the presence of BAK. However, BAK itself strongly aggravated complement activation by both activators.

CONCLUSIONS

Carteolol, timolol, betaxolol and latanoprost did not activate complement system. On the contrary, the beta-blockers timolol and betaxolol exerted an anti-inflammatory effect by preventing complement activation. The deleterious effect of benzalkonium seems to have been neutralized within the preserved eyedrops through a mechanism that remains to be elucidated. Our study suggests that inflammatory signs in glaucoma patients should not be attributed to complement activation by antiglaucoma drugs.

Methylparaben in Anopheles gambiae s.l. sugar meals increases longevity and malaria oocyst abundance but is not a preferred diet

The antimicrobial and antifungal chemical methylparaben (methyl-4-hydroxybenzoate) was added to the adult sucrose diet of Anopheles gambiae and Anopheles arabiensis, and its effect on longevity was determined. In all cases, significant increases in longevity were observed when 0.2% (w/v) methylparaben was added to meals that were refreshed weekly. When fresh sugar diet was refreshed daily, no increase in longevity was observed due to methylparaben suggesting that the effect of methylparaben is to preserve the quality of the sugar diet. No longevity effect of providing pure water in addition to sugar- or methylparaben-supplemented meals was observed. Feeding preference tests were performed to determine whether meals containing methylparaben were preferred, and whether, when given no choice but the less-preferred diet, mosquitoes would consume less sugar. Using the stable carbon isotope (13)C in paired tests, we show that the sugar diet containing methylparaben was clearly avoided by A. gambiae but not A. arabiensis. Little effect of methylparaben on the total amount of sugar consumed was observed when mosquitoes were given no diet choice. Methylparaben effects on Plasmodium cynomolgi B oocyst formation and encapsulation were observed in a normal A. gambiae stock and one which encapsulates at a high frequency. Nearly two-fold increases in the number of both normal and encapsulated oocysts were observed as a result of methylparaben in the diet. Because of its longevity effects, we have implemented methylparaben use for all mosquitoes in our holdings and recommend it as a routine sugar meal supplement.

The Importance of the Cosolvent Propylene Glycol on the Antimicrobial Preservative Efficacy of a Pharmaceutical Formulation by DOE-Ruggedness Testing

The aim of this study was to statistically evaluate the influence of the concentration of the co-solvent propylene glycol on the preservative efficacy of a complex pharmaceutical suspension-emulsion formulation containing methyl- and propylparaben. Preservative Efficacy Tests (PETs) were performed using the validated pharmacopoeial methodology with five test organisms over 1 month on lab-scale test formulations. These were independently prepared according to a Box-Behnken experimental design with a triplicate central point at 0.22% m/m methylparaben, 0.22% m/m propylparaben, and 2.75% m/m propylene glycol, and with an additional corner point of the Box-Behnken cube. We evaluated the preservative efficacies against the criteria of the United States Pharmacopeia (USP) and European Pharmacopoeias (PhEur) for formulations for oral use, as well as by the statistical comparison of the slopes obtained by linear regression of log (CFU/g) vs. time. With an initial bacterial challenge of 10(6) CFU/g for each of the three bacterial strains, no survivals were detected after 7 days. For the two fungal strains, box plots and analysis of variance showed significant, concentration-dependent, main effects: the three variables significantly influenced the kill-rate of C. albicans, while A. niger was predominantly influenced by the cosolvent propylene glycol, and only to a minor extent by methylparaben and not at all by propylparaben. These findings were confirmed by taking the pharmacopoeial criteria as the evaluation basis, where the dominant influence of propylene glycol concentration is apparent. It was concluded that the cosolvent propylene glycol is at least of equal preservative importance than both parabens.

Efficacy and safety levels of preserved and preservative-free tafluprost are equivalent in patients with glaucoma or ocular hypertension: results from a pharmacodynamics analysis

PURPOSE

Tafluprost is a new prostaglandin F(2alpha) (PGF(2alpha)) derivative in development for the treatment of glaucoma. Tafluprost is the first PGF(2alpha) analogue with a preservative-free formulation.

METHODS

This randomized, investigator-masked, multicentre, crossover phase III study evaluated the pharmacodynamics and safety of preserved and preservative-free tafluprost 0.0015% eyedrops administered for 4 weeks in 43 patients with open-angle glaucoma or ocular hypertension. The primary variable was change from baseline in overall diurnal intraocular pressure (IOP) at 4 weeks. Adverse events and other safety parameters were also analysed.

RESULTS

Decreased IOP was clearly observed with both formulations at week 1 and was sustained until week 4. The overall treatment difference (preservative-free versus preserved formulations) at week 4 was 0.01 mmHg (95% confidence interval - 0.46 to 0.49; p = 0.96). There were no unexpected safety-related findings. Both formulations were well tolerated and most adverse events were ocular and mild in severity.

CONCLUSIONS

THE reduction in IOP achieved by preservative-free tafluprost is equivalent to that obtained with the preserved formulation. The preservative-free formulation was generally well tolerated.

Quantitative analysis of conjunctival goblet cells after chronic application of topical drops

INTRODUCTION

Chronic topical glaucoma therapy has been reported to cause deleterious changes to the ocular surface epithelial layers. We compare changes in the number of goblet cells after chronic exposure to latanoprost preserved with 0.02% benzalkonium chloride (BAK) eye drops (Xalatan; Pfizer, NY, USA), travoprost preserved with sofZia eye drops (Travatan Z; Alcon, Fort Worth, TX, USA), or preservative-free artificial tears (Refresh Plus; Allergan, Irvine, CA, USA).

METHODS

Fifteen New Zealand white rabbits were randomised into groups of five (one eye was randomised for treatment) and received once-daily topical application of one of the three treatments for 30 days. Enucleation was performed at the end of the study followed by histologic analysis using mucin stains to identify goblet cells. Goblet cells were quantified and analysed using Student t tests to compare means between groups.

RESULTS

Goblet cells per high-power field were 2.21 (+/-0.40) in the latanoprost with BAK group, 6.02 (+/-1.20) in the travoprost with sofZia group, and 7.03 (+/-1.33) in the preservative-free artificial tear group. The number of goblet cells in the latanoprost with BAK group was significantly lower than the other two groups (P=0.0001). There was no statistically significant difference in goblet cell numbers between the travoprost with sofZia and preservative-free artificial tear group (P=0.24).

CONCLUSION

Our study illustrates that, in this animal model, once-daily dosing of latanoprost with 0.02% BAK resulted in goblet cell loss compared with dosing with either travoprost with sofZia or preservative-free artificial tears.

Controlled release of preservatives using dealuminated zeolite Y

This study demonstrates that dealuminated zeolite Y can act as a depot after adsorption of phenol derived preservatives. Upon suspension of zeolite loaded with the preservative m-cresol, equilibrium was quickly reached between free and adsorbed m-cresol. The equilibrium concentration of m-cresol was below 1 mM; however, it was enough to kill bacteria such as Escherichia coli and Staphylococcus aureus under metabolically active conditions. Killing of bacteria was not obtained under non-proliferating conditions and m-cresol was only released from the zeolite upon bacterial activity. Together, these results demonstrate an interesting potential use of dealuminated zeolite Y containing adsorbed preservatives for preventing microbial growth in numerous applications in industry and clinical setting.

Corneal critical barrier against the penetration of dexamethasone and lomefloxacin hydrochloride: evaluation by the activation energy for drug partition and diffusion in cornea

The cornea is a solid barrier against drug permeation. We searched the critical barrier of corneal drug permeation using a hydrophobic drug, dexamethasone (DM), and a hydrophilic drug, lomefloxacin hydrochloride (LFLX). The activation energies for permeability of DM and LFLX across the intact cornea were 88.0 and 42.1 kJ/mol, respectively. Their activation energies for permeability across the cornea without epithelium decreased to 33.1 and 16.6 kJ/mol, respectively. The results show that epithelium is the critical barrier on the cornea against the permeation of a hydrophobic drug of DM as well as a hydrophilic drug of LFLX. The activation energy of partition for DM (66.8 kJ/mol) was approximately 3-fold larger than that of diffusion (21.2 kJ/mol). The results indicate that the partition for the hydrophobic drug of DM to the corneal epithelium is the primary barrier. Thermodynamic evaluation of activation energy for the drug permeation parameters is a good approach to investigate the mechanism of drug permeability.