Stability Study Through Water Activity Measurements for Dispensed Powdered Raw Materials.

BACKGROUND: Holding times for raw materials are relevant since they enable us to understand the allowable time that a raw material can be kept under ideal storage conditions before the start of the manufacturing process without its quality attributes being affected. The quantification of water activity can be used as an indicator of the microbiological, physicochemical, and organoleptic stability of a specimen, since low water activity retards autohydrolysis and microbiological growth. OBJECTIVE: The main purpose of this investigation was to test the stability of powdered raw materials for a maximum holding time of 8 days through water activity measurements. Thus microbiological, physicochemical, and organoleptic measurements were carried out in parallel and simultaneously to experimentally establish a relationship between the status of the water activity of processed raw materials and the microbiological, physicochemical, and organoleptic results. METHODS: The raw materials were stored for a maximum holding time of 8 days, in accordance with United States Pharmacopeia monographs. For all the raw materials tested, water activity measurements were performed using the dew point chilled-mirror method on days 0, 3, and 8. On days 0 and 8, microbiological, physicochemical, and organoleptic assessments were performed. RESULTS: It was established that under these storage conditions, the processed raw materials exhibited water activity below 0.60 during the entire holding time. However, there were statistically significant differences in water activity levels between days 0, 3, and 8 (ANOVA P < 0.05). Despite observing statistically significant differences between days, the microbiological, physicochemical, and organoleptic features were within specification at those water activity levels below 0.60. CONCLUSIONS: Water activity below 0.60 does not allow the growth of microorganisms, and the organoleptic and physicochemical features remain unperturbed. The results indicate that water activity can be used as an indicator of the microbiological load and chemical stability of the raw materials tested. HIGHLIGHTS: This research provides evidence that corroborates that water activity status may be used as a reliable indicator for the microbiological burden and physicochemical features of pharmaceutical material during stability studies.

Validation of a Rapid Microbiological Method for the Detection and Quantification of the Burkholderia cepacia Complex in an Antacid Oral Suspension.

BACKGROUND: Despite the broad adoption of Soleris® technology in the food industry as semiquantitative method, it is almost completely unexplored in the pharmaceutical industry as a quantitative method for quantification of Burkholderia cepacia complex (Bcc). OBJECTIVE: The efficacy of an automated growth-based system for a quantitative determination of the Bcc in an antacid oral suspension was studied. The main purpose of this validation study was to prove that the alternative method's entire performance is not inferior to the conventional method for a quantitative determination of Bcc. METHOD: The antacid oral suspension's preservatives were neutralized, leading to the Burkholderia complex's recovery by means of the alternative method and the reference method. A calibration curve was generated for each strain by plotting DTs relative to the corresponding log CFU values. An equivalence of results was done through the construction of calibration curves that allowed the establishment of numerically equivalent results between the enumeration data from the reference method and the alternative method. RESULTS: Thus following the guidelines of USP, essential validation parameters were shown, such as equivalence of results (CC >0.95), linearity (R2 >0.9025), accuracy (% recovery >70%), operating range, precision and ruggedness (DS <5 and CV <35%), specificity (inclusivity and exclusivity), limit of detection (LOD), and limit of quantification (LOQ). CONCLUSIONS: It was shown that all the test results obtained from the alternative method were in statistical agreement with the standard method. Thus this new technology was found to meet all the validation criteria needed to be considered as an alternative method for the quantification of the Burkholderia complex in the antacid oral suspension tested. HIGHLIGHTS: As outlined in USP chapter <1223> and demonstrated in this research the implementation of alternative methods can offer benefits in execution and automation while improving accuracy, sensitivity, and precision and can reduce the microbiological process time compared to the traditional ones.

Performance Equivalence and Validation of a Rapid Microbiological Method for Detection and Quantification of Yeast and Mold in an Antacid Oral Suspension.

Alternative and rapid microbiological methods can be effective replacements for more traditional plating approaches for ensuring quality and safety in the pharmaceutical industry. This article compares the efficacy of the Soleris automated method and the traditional plate-count method for the quantitative detection of yeasts and molds at three different microbial bioburden levels. Validation testing was carried out using an antacid oral suspension (aluminum hydroxide 4% + magnesium hydroxide 4% + simethicone 0.4%). Equivalence of data between detection time and colony-forming units was established for both the alternative and the conventional methodologies. Using probability of detection, linear Poisson regression, Fisher's test, and multifactorial analysis of variance (ANOVA), all results from the rapid method were shown to be in statistical agreement with the those of the reference plating procedures. The limits of detection and quantification were statistically similar for both methods (Fisher's exact test, P > 0.05), showing that the alternative method is not inferior in performance to the reference method. Essential validation parameters such as precision (standard deviation <5, coefficient of variance <35%), accuracy (>70%), linearity (R2 >0.9025), ruggedness (ANOVA, P < 0.05), operative range, and specificity were determined. It was shown that all the test results obtained using the alternative method were in statistical agreement with the those of the standard plate-count method. Thus, this new technology was found to meet all the validation criteria needed to be considered as an alternative method for yeast and mold quantification in the antacid oral suspension tested. However, taking into account that the present validation was carried out utilizing A. brasiliensis and C. albicans as suitable models for yeasts and molds and with an antacid oral suspension as a pharmaceutical matrix, further investigation will be required to qualify Soleris technology for other environmental isolates and recovery of these isolates from production batches.

AmrZ regulates cellulose production in Pseudomonas syringae pv. tomato DC3000.

In Pseudomonas syringae pv. tomato DC3000, the second messenger c-di-GMP has been previously shown to stimulate pellicle formation and cellulose biosynthesis. A screen for genes involved in cellulose production under high c-di-GMP intracellular levels led to the identification of insertions in two genes, wssB and wssE, belonging to the Pto DC3000 cellulose biosynthesis operon wssABCDEFGHI. Interestingly, beside cellulose-deficient mutants, colonies with a rougher appearance than the wild type also arouse among the transposants. Those mutants carry insertions in amrZ, a gene encoding a transcriptional regulator in different Pseudomonas. Here, we provide evidence that AmrZ is involved in the regulation of bacterial cellulose production at transcriptional level by binding to the promoter region of the wssABCDEFGHI operon and repressing cellulose biosynthesis genes. Mutation of amrZ promotes wrinkly colony morphology, increased cellulose production and loss of motility in Pto DC3000. AmrZ regulon includes putative c-di-GMP metabolising proteins, like AdcA and MorA, which may also impact those phenotypes. Furthermore, an amrZ but not a cellulose-deficient mutant turned out to be impaired in pathogenesis, indicating that AmrZ is a key regulator of Pto DC3000 virulence probably by controlling bacterial processes other than cellulose production.

Responses to elevated c-di-GMP levels in mutualistic and pathogenic plant-interacting bacteria.

Despite a recent burst of research, knowledge on c-di-GMP signaling pathways remains largely fragmentary and molecular mechanisms of regulation and even c-di-GMP targets are yet unknown for most bacteria. Besides genomics or bioinformatics, accompanying alternative approaches are necessary to reveal c-di-GMP regulation in bacteria with complex lifestyles. We have approached this study by artificially altering the c-di-GMP economy of diverse pathogenic and mutualistic plant-interacting bacteria and examining the effects on the interaction with their respective host plants. Phytopathogenic Pseudomonas and symbiotic Rhizobium strains with enhanced levels of intracellular c-di-GMP displayed common free-living responses: reduction of motility, increased production of extracellular polysaccharides and enhanced biofilm formation. Regarding the interaction with the host plants, P. savastanoi pv. savastanoi cells containing high c-di-GMP levels formed larger knots on olive plants which, however, displayed reduced necrosis. In contrast, development of disease symptoms in P. syringae-tomato or P. syringae-bean interactions did not seem significantly affected by high c-di-GMP. On the other hand, increasing c-di-GMP levels in symbiotic R. etli and R. leguminosarum strains favoured the early stages of the interaction since enhanced adhesion to plant roots, but decreased symbiotic efficiency as plant growth and nitrogen contents were reduced. Our results remark the importance of c-di-GMP economy for plant-interacting bacteria and show the usefulness of our approach to reveal particular stages during plant-bacteria associations which are sensitive to changes in c-di-GMP levels.