Regression control chart with unknown parameters for detection of out-of-trend results in pharmaceutical on-going stability studies.

The main purpose of on-going stability studies in pharmaceutical industry is to test whether the regulatory requirement regarding the shelf life is fulfilled when the drug is already produced for patients. That is, the estimated shelf life of the products agrees with the shelf life claimed during the registration of the drug. The monitored process is the change in certain attributes (e.g. pH) of the drug products over time and the estimated shelf life for a given batch is determined based on the results of the monitoring. Out-of-trend (OOT) data points in stability studies distort the estimated trend, which results in distorted estimation of shelf life. Undetected OOT points could lead to overestimated shelf life, which may results in drug products with non-acceptable quality, continuously distributed to patients. In this paper, the regression control chart method is adapted for pharmaceutical stability studies to detect OOT points within the studies. The challenge is that the sample size is small. Usually, in a study the collected data is limited to 8-10 points. The parameters (true regression line and residual variance) of the process cannot be taken as known and the uncertainty of the estimated parameters is rather large. Therefore, the generally used regression control chart that utilizes the Shewhart method in which the parameters are known, may not be used. The proposed method in this paper takes the uncertainty of the parameters into account. Also adaptations of the proposed method for different ANCOVA models - such as a) every batch has the same true intercept and slope, b) every batch has the same slope but the intercepts differ, c) batches have different intercepts and slopes as well - are presented. When the proposed method employs the information obtained from the ANCOVA test, the statistical power of OOT detection is increased, i.e. the OOT detection is more effective.

Best conditions for biodegradation of diesel oil by chemometric tools.

Diesel oil biodegradation by different bacteria-yeast-rhamnolipids consortia was tested. Chromatographic analysis of post-biodegradation residue was completed with chemometric tools (ANOVA, and a novel ranking procedure based on the sum of ranking differences). These tools were used in the selection of the most effective systems. The best results of aliphatic fractions of diesel oil biodegradation were observed for a yeast consortia with Aeromonas hydrophila KR4. For these systems the positive effect of rhamnolipids on hydrocarbon biodegradation was observed. However, rhamnolipids addition did not always have a positive influence on the biodegradation process (e.g. in case of yeast consortia with Stenotrophomonas maltophila KR7). Moreover, particular differences in the degradation pattern were observed for lower and higher alkanes than in the case with C22. Normally, the best conditions for "lower" alkanes are Aeromonas hydrophila KR4 + emulsifier independently from yeasts and e.g. Pseudomonas stutzeri KR7 for C24 alkane.

Best conditions for biodegradation of diesel oil by chemometric tools

Diesel oil biodegradation by different bacteria-yeast-rhamnolipids consortia was tested. Chromatographic analysis of post-biodegradation residue was completed with chemometric tools (ANOVA, and a novel ranking procedure based on the sum of ranking differences). These tools were used in the selection of the most effective systems. The best results of aliphatic fractions of diesel oil biodegradation were observed for a yeast consortia with Aeromonas hydrophila KR4. For these systems the positive effect of rhamnolipids on hydrocarbon biodegradation was observed. However, rhamnolipids addition did not always have a positive influence on the biodegradation process (e.g. in case of yeast consortia with Stenotrophomonas maltophila KR7). Moreover, particular differences in the degradation pattern were observed for lower and higher alkanes than in the case with C22. Normally, the best conditions for "lower" alkanes are Aeromonas hydrophila KR4 + emulsifier independently from yeasts and e.g. Pseudomonas stutzeri KR7 for C24 alkane.

Long-term psychological and sexual outcomes of severe penile hypospadias repair.

INTRODUCTION: Hypospadias is the most common penis malformation, and there exist a variety of surgical approaches used to correct the abnormal position of the meatus. Although the long-term outcomes of surgery are considered important for psychosexual development, only a few attempts have been made to evaluate patient satisfaction. AIM: The aim of our study was to evaluate surgical results and psychosocial adaptations in a homogeneous group of subjects with severe penile hypospadias who underwent the same types of surgical repairs during childhood and compare the results to data obtained from age-matched healthy controls. METHODS: In this cross-sectional study, 104 men (between 24 and 42 years old) who underwent an uncomplicated two-stage hypospadias repair in their childhood and 63 age-matched healthy men without genital malformations completed the questionnaire. MAIN OUTCOME MEASURES: Difference in self-perception assessed by a 15-item questionnaire regarding psychosexual well-being and penile appearance between subjects with corrected hypospadias and healthy participants. RESULTS: On average, subjects with a hypospadias repair were less satisfied with their genital appearance; however, they were more satisfied with their sex lives compared to healthy controls. The meatus distance was approximately 1.5 cm from the tip of the penis after surgical correction. None of the postoperative surgical results correlated with patient satisfaction. Furthermore, the small percentage of patients (11%) who were very unsatisfied with their surgical outcomes had no significant differences in surgical outcomes compared to satisfied patients. However, there was a significant difference between the two groups in almost all psychological outcome measures. CONCLUSIONS: In adults who underwent an uncomplicated ventral repair of a severe penile hypospadias 20-30 years earlier, healthy psychosexual development was achieved despite the lack of a glanular meatus. Early identification of unsatisfied patients is important for appropriate long-term follow-up and counseling.

Content uniformity and assay requirements in current regulations.

The acceptance of a tablet batch is based both on the content uniformity test and on the assay. It is shown that these two characteristics are not independent, and the acceptance criteria for them are not even consistent. For content uniformity range three methods of calculation are compared: the present European Pharmacopoeia method, a tolerance range method with improved k tolerance factor and a one-way random effects analysis of variance model. To resolve the inconsistency several options are discussed: applying the holistic content uniformity range alone; using content uniformity standard deviation and assay mean simultaneously or applying a criterion based on Taguchi's quadratic loss function.

Enantioseparation of chiral alcohols by complex formation and subsequent supercritical fluid extraction.

The very first application of supercritical fluid extraction (SFE) on enantioseparation of alcohols is discussed. Resolution of three chiral alcohols (trans-2-chloro-cyclohexanol, trans-2-bromo-cyclohexanol, and trans-2-iodo-cyclohexanol) were performed by partial complexation with (-)-O,O'-dibenzoyl-(2R,3R)-tartaric acid monohydrate (DBTA). DBTA formed diastereomeric complexes with all S,S-enantiomers stable enough to extract the unreacted alcohols with supercritical carbon dioxide. Resolution efficiency increased with the size of halogen substituents, and by the proper selection of molar ratio, pure (-)-R,R-trans-2-iodo-cyclohexanol (ee > 99%, yield: 39%) or (+)-S,S-trans-2-iodo-cyclohexanol (ee = 98%, yield: 8%) were prepared in one process step. Achieved resolution efficiency values were much higher in all resolution procedures than in any other known enantioseparation of these racemic compounds. The developed method offers an environmentally friendly, efficient alternative of currently applied resolution processes, also on a preparative scale.