Naked Plasmid DNA Formulation: Effect of Different Disaccharides on Stability after Lyophilisation

Since plasmid DNA (pDNA) is unstable in solution, lyophilisation can be used to increase product shelf life. To prevent stress on pDNA molecules during lyophilisation, cryo- and lyoprotectants have to be added to the formulation. This study assessed the effect of disaccharides on naked pDNA stability after lyophilisation using accelerated stability studies. Naked pDNA was lyophilised with sucrose, trehalose, maltose or lactose in an excipient/DNA w/w ratio of 20. To one part of the vials extra residual moisture was introduced by placing the vials half opened in a 25°C/60% RH climate chamber, before placing all vials in climate chambers (25°C/60% RH and 40°C/75% RH) for stability studies. An ex vivo human skin model was used to assess the effect of disaccharides on transfection efficiency. Lyophilisation resulted in amorphous cakes for all disaccharides with a residual water content of 0.8% w/w. Storage at 40°C/75% RH resulted in decreasing supercoiled (SC) purity levels (sucrose and trehalose maintained approximately 80% SC purity), but not in physical collapse. The addition of residual moisture (values between 7.5% and 10% w/w) resulted in rapid collapse except for trehalose and decreasing SC purity for all formulations. In a separate experiment disaccharide formulation solutions show a slight but significant reduction (<3% with sucrose and maltose) in transfection efficiency when compared to pDNA dissolved in water. We demonstrate that disaccharides, like sucrose and trehalose, are effective lyoprotectants for naked pDNA.     

西番莲采后品质劣变及贮藏保鲜技术研究进展

西番莲(Passiflora caerulea)是一种营养丰富的热带亚热带特色水果,采后易发生果实品质劣变现象,是制约采后西番莲果实保鲜期的重要因素。本文就西番莲采后果实褶皱及失重、果皮色泽变化、营养物质含量减少和采后病害发生等品质劣变机理,及其低温、热处理、包装、1-MCP、多糖和化学保鲜剂等西番莲果实采后保鲜技术的国内外相关研究进行综述,以期为维持西番莲果实贮藏品质、延长果实保鲜期提供指导。     

Stability Enhancement of Drug Layered Pellets in a Fixed Dose Combination Tablet

The purpose of this research was to develop a stable fixed dose combination tablet for a model DPP-IV inhibitor and metformin hydrochloride. The dipeptidyl peptidase IV (DPP-IV) inhibitor was particularly challenging to formulate due to its significant chemical instability and moisture sensitivity. Various formulation strategies were investigated and placed on accelerated stability to determine the lead approach and critical quality attributes. The lead formulation investigated was a drug layered pellet containing the DPP-IV inhibitor, which was further coated with various seal coats and moisture barriers, then compressed into a tablet with compression aids and granulated metformin hydrochloride. The investigations revealed that the drug layered pellets compressed into a fixed dose combination tablet yielded a unique stability enhancement. The stability was highly dependent on the final tablet water content and could be further improved by the addition of moisture barrier coatings. A fundamental understanding of the key critical quality attributes for the fixed dose combination product containing a DPP-IV inhibitor and metformin hydrochloride as an oral solid dosage form were established. This research identified a formulation approach to enable a successful commercial product to be developed.     

Food packaging’s materials: A food safety perspective

Food packaging serves purposes of food product safety and easy handling and transport by preventing chemical contamination and enhancing shelf life, which provides convenience for consumers. Various types of materials, including plastics, glass, metals, and papers and their composites, have been used for food packaging. However, owing to consumers’ increased health awareness, the significance of transferring harmful materials from packaging materials into foods is of greater concern. This review highlights the interactions of food with packaging materials and elaborates the mechanism, types, and contributing factors of migration of chemical substances from the packaging to foods. Also, various types of chemical migrants from different packaging materials with their possible impacts on food safety and human health are discussed. We conclude with a future outlook based on legislative considerations and ongoing technical contributions to optimization of food–package interactions.     

Shelf life and safety aspects of chilled cooked and peeled shrimps (Pandalus borealis) in modified atmosphere packaging

AIMS: To evaluate the growth of Listeria monocytogenes and shelf life of cooked and peeled shrimps in modified atmosphere packaging (MAP). METHODS AND RESULTS: Storage trials with naturally contaminated cooked and peeled MAP shrimps (Pandalus borealis) were carried out at 2, 5 and 8 degrees C. Challenge tests at the same conditions were performed after inoculation with Listeria monocytogenes. Both storage trials and challenge tests were repeated after 4 months of frozen storage (-22 degrees C). Brochothrix thermosphacta and Carnobacterium maltaromaticum were responsible for sensory spoilage of cooked and peeled MAP shrimps. In challenge tests, growth of L. monocytogenes was observed at all of the storage temperatures studied. At 5 and 8 degrees C the concentration of L. monocytogenes increased more than a 1000-fold before the product became sensory spoiled whereas this was not observed at 2 degrees C. Frozen storage had only a minor inhibiting effect on growth of L. monocytogenes in the thawed product. CONCLUSIONS: To prevent L. monocytogenes becoming a safety problem, cooked and peeled MAP shrimps should be distributed at 2 degrees C and with a maximum shelf life of 20-21 d. At higher temperatures shelf life is significantly reduced. SIGNIFICANCE AND IMPACT OF THE STUDY: Information is provided to establish shelf life of cooked and peeled MAP shrimps.     

Influence of Formulation and Processing Factors on Stability of Levothyroxine Sodium Pentahydrate

Stability of formulations over shelf-life is critical for having a quality product. Choice of excipients, manufacturing process, storage conditions, and packaging can either mitigate or enhance the degradation of the active pharmaceutical ingredient (API), affecting potency and/or stability. The purpose was to investigate the influence of processing and formulation factors on stability of levothyroxine (API). The API was stored at long-term (25°C/60%RH), accelerated (40°C/75%RH), and low-humidity (25°C/0%RH and 40°C/0%RH) conditions for 28 days. Effect of moisture loss was evaluated by drying it (room temperature, N₂) and placed at 25°C/0%RH and 40°C/0%RH. The API was incubated with various excipients (based on package insert of marketed tablets) in either 1:1, 1:10, or 1:100 ratios with 5% moisture at 60°C. Commonly used ratios for excipients were used. The equilibrium sorption data was collected on the API and excipients. The API was stable in solid state for the study duration under all conditions for both forms (potency between 90% and 110%). Excipients effect on stability varied and crospovidone, povidone, and sodium laurel sulfate (SLS) caused significant API degradation where deiodination and deamination occurred. Moisture sorption values were different across excipients. Crospovidone and povidone were hygroscopic whereas SLS showed deliquescence at high RH. The transient formulation procedures where temperature might go up or humidity might go down would not have major impact on the API stability. Excipients influence stability and if possible, those three should either be avoided or used in minimum quantity which could provide more stable tablet formulations with minimum potency loss throughout its shelf-life.     

Postharvest biology and technology of sapota: a concise review

Sapota is cultivated in many countries of tropical and subtropical climate. It is delicious, nutritive, and commercially grown mainly for fresh consumption. Postharvest life of sapota is very short due to its highly perishable nature and other many reasons such as quick ripening, faster senescence, rapid loss of moisture, microbial spoilage, and fruit sensitivity to cold storage. To maintain and/or increase the shelf life of sapota, proper postharvest management is required. Unfortunately, very little work has been done so far, with limited success, leaving scarce literature published on postharvest management technologies of sapota. Different pre and postharvest treatments to reduce metabolic activity and quality loss have been suggested. Moreover, proper storage temperature and packaging may be used to increase the shelf life of fruits. This review explores the postharvest technologies adopted to enhance the shelf life of sapota during storage and distribution channel.     

Vaccine stability study design and analysis to support product licensure

Stability evaluation supporting vaccine licensure includes studies of bulk intermediates as well as final container product. Long-term and accelerated studies are performed to support shelf life and to determine release limits for the vaccine. Vaccine shelf life is best determined utilizing a formal statistical evaluation outlined in the ICH guidelines, while minimum release is calculated to help assure adequate potency through handling and storage of the vaccine. In addition to supporting release potency determination, accelerated stability studies may be used to support a strategy to recalculate product expiry after an unintended temperature excursion such as a cold storage unit failure or mishandling during transport. Appropriate statistical evaluation of vaccine stability data promotes strategic stability study design, in order to reduce the uncertainty associated with the determination of the degradation rate, and the associated risk to the customer.     

Immobilization of urease on gelatin — poly (HEMA) copolymer preparation and characterization

Urease was immobilized onto gelatin-poly (HEMA) copolymer by covalent linkage. Maximum amount of urease was immobilized onto the support at a pH of 8.5. The optimal pH of the immobilized urease was similar to that of free urease; the optimal temperature showed an increase of 10 °C over the free enzyme. The stability of the immobilized urease for a range of pH, temperature and shelf life was greater than the corresponding values for the free enzyme. The same result was obtained for k _m also.Grateful acknowledgement is made to CSIR, Govt. of India for the research associateship conferred on Dr. M. Chellapandian which helped the progress of this piece of research investigation.     

Using Manufacturing Design Space Concepts for Stability Risk Assessment—Gabapentin NIPTE/FDA Case Study

A quantitative, model-based risk assessment process was evaluated using Bayesian parameter estimation to determine the posterior distribution of the probability of a model tablet formulation’s (gabapentin) ability to meet end-of-expiry stability criteria-based manufacturing controls. Experimental data was obtained from an FDA-supported, multi-year project that involved researchers at nine universities working collaboratively with industrial and governmental scientists under the leadership of the National Institute for Pharmaceutical Technology and Education (NITPE). The risk assessment process involved the development of a design space manufacturing model and shelf life stability model that shared stability-related critical quality attributes (CQAs). Monte Carlo simulations of the design space and shelf life models that uses model parameter uncertainty to estimate the probability of shelf life failure as a function of manufacturing control. The resultant linked design space and shelf life stability models were tested by comparing model predicted and observed long-term stability data generated under a variety of pilot scale production conditions.     

Microbiological and biochemical changes in pearl spot (Etroplus suratensis Bloch) stored under modified atmospheres

AIMS: This study aimed to determine the effect of packaging [air, modified atmosphere (MA)] on microbial growth, sensory and chemical parameters and also on shelf life of fresh pearl spot (Etroplus suratensis Bloch) and on the selection of microbial association. METHODS AND RESULTS: Fresh pearl spot (whole, gutted) were packaged under both 100% air and MAs (40%CO(2)/60% O(2), 50%CO(2)/50%O(2), 60% CO(2)/40%O(2), 70% CO(2)/30% O(2) and 40% CO(2)/30% O(2)/30% N(2)) and stored at 0 degrees C. Microbial growth (counts of total aerobic bacteria, H(2)S-producing bacteria, Lactic acid bacteria, Brochothrix thermosphacta, yeast and mould), chemical spoilage indicators (pH, total volatile basic nitrogen) and sensory characteristics were monitored. Microbial changes in Pearl spot packed under 100% air and 40% CO(2)/30%O(2)/30% N(2) were similar. The total volatile basic nitrogen values increased, but the values never exceeded the acceptability limit of 25 mg 100 g(-1). CONCLUSIONS: MA 60% CO(2) : 40%O(2) was found to be better with a shelf life of 21 days whereas air stored samples had a shelf-life of 12-14 days only. SIGNIFICANCE AND IMPACT OF THE STUDY: Storage of pearl spot under MAs 60% CO(2) : 40%O(2) is a promising method to extend shelf-life. Longer shelf life expands the market potential of pearl spot and reduces waste during distribution and retail display.     

Kinetic Model Development for Accelerated Stability Studies

Accelerated stability coupled with modeling to predict the stability of compounds, blends, and products at long-term storage conditions provides significant benefits in science-based decision-making throughout drug substance and drug product development. The study can often be completed, including data analysis in the space of three working weeks, and the information gathered and learning made in this time period can rival years of traditional analysis. The speed of the studies allows an earlier assessment of risk to quality enabling appropriate risk mitigation strategies to be implemented in a timely manner. The scientific foundation is based upon Arrhenius kinetic equations that can be linear or nonlinear in time, and can be based upon water vapor pressure or liquid water activity (relative humidity). A variety of kinetic models are evaluated, and the best model is chosen based upon both Bayesian information criteria and an automated assessment of kinetic model parameters fitting within acceptable ranges. Confidence intervals are estimated based upon a bootstrapping approach. Moisture vapor transmission rate models are applied on top of the resulting kinetic models in order to simulate different packaging types and the use of desiccant. The kinetic models are integrated with the prediction of packaging humidity over time to create a long-term prediction of impurities and other phenomena. The resulting models have been shown to be useful for not only the prediction of drug product impurities in long-term storage but other physical phenomena as well such as hydrate development and solvate loss.     

Stability of vaccines – Bridging from stability data to continuous safety and efficacy throughout shelf life – An always reliable approach?

Stability studies are important tools to reliably ensure that efficacy and safety of medicinal products will remain unchanged from release of drug product until the end of shelf life. For complex medicinal products such as biological medicinal products, including vaccines, design and conduct of such studies requires particularly careful considerations in order to ensure that technical data resulting from stability studies are indeed indicative for unchanged clinical performance. Ideally, relevance of specifications controlled by stability studies as well as definition of shelf life should be justified by acceptable clinical data obtained with product at the end of the shelf life claimed.     

Effects of fluctuating thermal regimes on cold survival and life history traits of the spotted wing Drosophila(Drosophila suzukii)

Drosophila suzukii is an invasive pest causing severe damages to a large panel of cultivated crops.To facili tate its biocontrol with stratcgies such as sterile or incompatible insect techniques,D.suzukid must be mass-produced and then stored and transported under low temperature.Prolonged cold exposure induces chill injuries that can be mitigated if the cold period is interrupted with short warming intervals,referred to as fluctuating thermal regimes(FTR).In this study,we tested how to optimally use FTR to extend the shelf life of D.suzukii under cold storage.Several FTR parameters were asessed:temperature(15,20,25℃),duration(0.5,1,2,3 h),and frequency(every 12,24,36,48 h)of warming intervals,in two wild-type lines and in two developmental stages(pupac and adults).Generally,FTR improved cold storage tolerance with respect to constant low temperatures(CLT).Cold mortality was lower when recovery temperature was 20℃ or higher,when duration was 2 h per day or longer,and when warming interruptions occurred frequently(every 12 or 24 h).Applying an optimized FTR protocol to adults greatly reduced cold mortality over long-term storage(up to 130 d).Consequences of FTR on fitness-related traits were also investigated.For adults,poststorage survival was unaffected by FTR,as was the case for female fecundity and male mating capacity.On the other hand,when cold storage occurred at pupal stage,postorage survival and male mating capacity were altered under CLT,but not under FTR.After storage of pupae,female fecundity was lower under FTR compared to CLT,suggesting an energy trade-off between repair of chill damages and C22 production.This study provides detailed information on the application and optimization of an FTR-based protocol for cold storage of D.suzuki that could be useful for the biocontrol of this pest.     

Optimization of the spray drying of a Paenibacillus polymyxa-based biopesticide on pilot plant and production scales

Spore survival and moisture content are two important properties of biopesticides, and both are related to field biocontrol efficacy and storage shelf life. In this study, Paenibacillus polymyxa (HY96-2) was spray-dried on both pilot plant and production scales, and the effects of inlet and outlet temperatures on spore survival and moisture content were investigated. The results showed that inlet temperatures ranging from 170 to 230 °C (at an outlet temperature of 80 °C) had no obvious effect on the two properties during pilot scale processing, although an inlet temperature of 230 °C resulted in higher feed speed. When the outlet temperature on the pilot scale was reduced from 100 to 80 °C, no obvious variations in spore survival and moisture content were found, while a further reduction from 80 to 65 °C resulted in a decline in spore survival from 81.0 to 67.0% and an increase in moisture content from 2.3 to 31.7%. These results indicate that both outlet temperature and moisture content have an effect on spore survival. Optimum inlet and outlet temperatures for P. polymyxa processing were 230 °C and 85–90 °C on a production scale. Under these conditions, spore survival and moisture content were 83.5–86.6% and 2.73––4.12%, respectively.     

Microbial spoilage and formation of biogenic amines in fresh and thawed modified atmosphere-packed salmon (Salmo salar) at 2 degrees C

AIMS: To evaluate the microbial spoilage, formation of biogenic amines and shelf life of chilled fresh and frozen/thawed salmon packed in a modified atmosphere and stored at 2 degrees C. METHODS AND RESULTS: The dominating microflora, formation of biogenic amines and shelf life were studied in two series of storage trials with naturally contaminated fresh and thawed modified atmosphere-packed (MAP) salmon at 2 degrees C. Photobacterium phosphoreum dominated the spoilage microflora of fresh MAP salmon at more than 10(6) cfu g(-1) and the activity of this specific spoilage organism (SSO) limited the shelf life of the product to ca 14 and 21 d in the two experiments. Despite the high levels of P. phosphoreum, less than 20 mg kg(-1) histamine was observed in fresh MAP salmon prior to sensory spoilage. Freezing eliminated P. phosphoreum and extended the shelf life of MAP salmon at 2 degrees C by 1-2 weeks. Carnobacterium piscicola dominated the spoilage microflora of thawed MAP salmon and probably produced the ca 40 mg kg(-1) tyramine detected in this product at the end of its shelf life. CONCLUSIONS: Photobacterium phosphoreum dominated the spoilage microflora of fresh MAP salmon but produced only small amounts of biogenic amines in this product. The elimination of P. phosphoreum by freezing allowed this bacteria to be identified as the SSO in fresh MAP salmon. SIGNIFICANCE AND IMPACT OF THE STUDY: The identification of P. phosphoreum as the SSO in fresh MAP salmon facilitates the development of methods to determine and predict the shelf life of this product, as previously shown with fresh MAP cod.     

Assessing distributions of estimated drug shelf lives in stability analysis

A stability study is usually conducted to ensure that a drug product can meet the approved specifications prior to its expiration dating period (shelf life). Several approaches for determination of drug shelf life assuming random batches have been proposed. In this paper, we examine sampling distributions of the estimated shelf lives proposed by Shao and Chow (1994, Biometrics 50, 753-763). An application to some stability data from the pharmaceutical industry is presented.     

Stability of some microginins synthesized by the cyanobacterium Woronichinia naegeliana (Unger) Elenkin

Microginins are linear oligopeptides synthesized by cyanobacteria. The literature data on their characteristics are scant. This study examined the influence of abiotic factors including pH, temperature, visible and ultraviolet radiation on the stability of the microginins FR3 (MG‐FR3), FR4 (MG‐FR4) and 757 (MG‐757) synthesized by Woronichinia naegeliana. In alkaline conditions (pH 9) only the concentration of MG‐757 was reduced significantly, by 14.3%. The tested microginins were stable at room temperature (half‐life 7–17 weeks). Boiling for one hour caused 26.1% decomposition of MG‐FR4 and 26.8% decomposition of MG‐757; MG‐FR3 was not significantly affected. Under visible radiation the initial content of MG‐FR4 declined 23.0%, but MG‐FR3 and MG‐757 proved insensitive to it. Treatment with a high dose of UV radiation (36 μmol m^?2 s^?1) caused the tested microginins to degrade by 13.8% to 21.4%. The study showed these microginins to be oligopeptides of high stability, the most stable of them being MG‐FR3.     

SENSORY SHELF-LIFE ESTIMATION OF ALFAJOR BY SURVIVAL ANALYSIS

Survival analysis methodology was used to estimate the shelf life of alfajor (a chocolate‐coated individually wrapped cake) at 20 and 35C by using results obtained from consumers when asked if they would accept or reject samples with different storage times. Sensory acceptability (measured by consumers), off‐flavor (measured by a trained panel) and moisture content were linearly related to time. These correlations were used to estimate values at the shelf‐life times calculated for 25 and 50% rejection probability. Survival analysis provided the following shelf‐life estimation: 74 days at 20C and 33 days at 35C for a 25% of rejection, 87 days at 20C and 39 days at 35C for a 50% of rejection. An alfajor stored at 20C having an acceptability value below 4.9 (1–9 hedonic scale) and off‐flavor intensity above 5.3 (0–10 scale) would be rejected by 25% of the consumers. Chemical data were not good shelf‐life predictors.     

Effects of ionizing radiation and modified atmosphere packaging on the shelf life of aqua-cultured sea bass (Dicentrarchus labrax)

The major problems concerning marketing and distribution of seafoods are their high perishability due mainly to contamination by spoilage and pathogenic microorganisms. The reduction, destruction or inhibition of microbial contaminants using single or combined treatments might lead to efficient preservation methods. In this research we examined the feasibility of modified atmosphere packaging and irradiation treatments on the extension of the shelf-life of fresh aqua-cultured sea bass Dicentrarchus labrax species. The quality and the freshness of sea bass packaged in modified atmosphere or γ-irradiated were evaluated by assessing their microbiological, sensory and chemical properties. The gas mixture composed by 60:35:5 CO₂/N₂/O₂ resulted as the best inhibitory treatment to extend the shelf life of sea bass. A major MDA containment and microbial decontamination in irradiated samples at 3 kGy were also found in respect to the control samples.