Summary report of PQRI Workshop on Nanomaterial in Drug Products: current experience and management of potential risks.

At the Product Quality Research Institute (PQRI) Workshop held last January 14-15, 2014, participants from academia, industry, and governmental agencies involved in the development and regulation of nanomedicines discussed the current state of characterization, formulation development, manufacturing, and nonclinical safety evaluation of nanomaterial-containing drug products for human use. The workshop discussions identified areas where additional understanding of material attributes, absorption, biodistribution, cellular and tissue uptake, and disposition of nanosized particles would continue to inform their safe use in drug products. Analytical techniques and methods used for in vitro characterization and stability testing of formulations containing nanomaterials were discussed, along with their advantages and limitations. Areas where additional regulatory guidance and material characterization standards would help in the development and approval of nanomedicines were explored. Representatives from the US Food and Drug Administration (USFDA), Health Canada, and European Medicines Agency (EMA) presented information about the diversity of nanomaterials in approved and newly developed drug products. USFDA, Health Canada, and EMA regulators discussed the applicability of current regulatory policies in presentations and open discussion. Information contained in several of the recent EMA reflection papers was discussed in detail, along with their scope and intent to enhance scientific understanding about disposition, efficacy, and safety of nanomaterials introduced in vivo and regulatory requirements for testing and market authorization. Opportunities for interaction with regulatory agencies during the lifecycle of nanomedicines were also addressed at the meeting. This is a summary of the workshop presentations and discussions, including considerations for future regulatory guidance on drug products containing nanomaterials.

Best practices for the development, scale-up, and post-approval change control of IR and MR dosage forms in the current quality-by-design paradigm.

In this whitepaper, the Manufacturing Technical Committee of the Product Quality Research Institute provides information on the common, best practices in use today in the development of high-quality chemistry, manufacturing and controls documentation. Important topics reviewed include International Conference on Harmonization, in vitro-in vivo correlation considerations, quality-by-design approaches, process analytical technologies and current scale-up, and process control and validation practices. It is the hope and intent that this whitepaper will engender expanded dialog on this important subject by the pharmaceutical industry and its regulatory bodies.

Alterations in electromyograms due to inactivity-induced atrophy of the human muscle.

Regarding disuse atrophy, numerous investigations attempting to determine typical alterations of EMG measured with concentric needle electrodes have led to mutually inconsistent results concerning amplitude, duration, polyphasy, and number of spikes of motor unit action potentials. Our study comprises 21 patients with one-sided atrophy of m. quadriceps caused by immobilization and a control group of 19 healthy persons. Sufferers of myogenic, neurogenic or haemostasiological diseases as well as all persons on medication were excluded. Quantification of atrophy was performed by myosonography and measuring of circumferences. Both methods proved to be equivalent and more precise than computed tomography. Nearly all values of measurements in patients and in the control group remained within the normal range. But comparing EMG of atrophic m. vastus lateralis with the non-immobilized muscle of the other side revealed statistically significant differences in amplitude (14.1% higher in the atrophic muscle), duration (6.5% longer), number of phases (+13.2%) and spikes (+13.9%). In the healthy muscles of the control group we found no significant differences between dominant and non-dominant legs. Partly consistent and partly contradictory results in other studies may be explained by: a) too few cases examined, b) absence of control groups and/or c) omission of comparisons between right and left legs, but also d) by differences in applied normal values and e) by decreased innervation due to pain, swelling, contractures or arthrodeses. A very important factor was f) the duration of immobilization and g) the time elapsed between the end of immobilization and the examination.

[A new aspect on the development of chronic middle ear diseases in patients with cleft palate]. / Ein neuer Aspekt zur Entstehung chronischer Mittelohrerkrankungen bei Patienten mit Gaumenspalte.

BACKGROUND: The prevalence of chronic middle ear disease in patients after surgery for cleft palate is about 50%. Aim of the present study was to analyse its morphological and physiological causes to prevent chronic atelectatic otitis media or cholesteatoma. METHODS: 15 adult patients with cleft palate were examined using middle ear microscopy, pure tone audiometry, EMG of the tensor veli palatini muscle and MRI of the Eustachian tube. RESULTS: 8 of 15 patients had chronic middle ear disease. With 13 of 15 patients single motor unit action potentials could be recorded from the tensor veli palatini muscle. MRI of the Eustachian tube revealed two decisive observations in patients with chronic middle ear disease: in 4 patients the pterygoid hamulus could not be detected, in all otitis patients the continuity of tensor veli palatini muscle was interrupted or disturbed by medial or lateral fixation. CONCLUSION: Chronic middle ear disease with cleft palate patients is basically caused by impaired muscular compliance of the Eustachian tube. Thus integrity of hamulus as well as tensor veli palatini muscle must become of crucial interest in cleft palate surgery.

Slow progression of juvenile metachromatic leukodystrophy 6 years after bone marrow transplantation.

Metachromatic leukodystrophy refers to a group of genetic neurologic diseases caused by deficiencies of the enzyme arylsulfatase A and the resulting accumulation of sulfatides in white matter. Bone marrow transplantation has been advocated as a treatment in an attempt to correct the enzyme deficiency. Such a transplant was performed in 1991 in a 16-year-old girl with a form of late juvenile metachromatic leukodystrophy caused by a homozygous P426L mutation in the arylsulfatase A gene. Engraftment was prompt and resulted in constant enzymatic normalization of circulating lymphocytes. The elevated urinary excretion of sulfatides remained unaffected. Clinical findings up until transplantation consisted of gait disturbances, impairment of cognitive functioning, and deterioration in school performance over several years. During a 6-year follow-up period, the patient's condition was subject to major fluctuations but, on the whole, findings showed slow neurologic and neurophysiologic deterioration. The clinical course observed after bone marrow transplantation probably more or less reflects the natural course expected in this form of late-onset metachromatic leukodystrophy.

[Electromyography studies of surgically managed knee ligament ruptures. A retrospective analysis of defined injury patterns]. / Elektromyographische Untersuchungen operativ versorgter Kniebandrupturen. Eine retrospektive Analyse definierter Verletzungsmuster.

In 52 patients (5 groups, average age 32.8 years) with operative treatment of knee ligament injuries cutaneous electromyograms (EMG) under dynamic and isometric conditions (100 N, 200 N, 300 N) were performed in an average of 61.2 weeks postoperatively. The subgroups consisted of 13 patients with operative reconstruction of the anterior cruciate ligament (ACL), 12 after reconstruction of the medial collateral ligament (MCL), 21 after combined ACL and MCL reconstruction and 6 patients with autologous or alloplastic ligament replacement, respectively. The control group consisted of seventeen young adults without a history of knee joint injuries. The intensified and filtered analogous signals of 8 investigated thigh muscles were digitalized and analysed with help of a specially developed computer program. In summary, group specific EMG-criteria reveal distinct ligamentomuscular inhibitory reflexes and, vice versa, EMG activities of thigh muscles may indicate tendencies for group specific criterion after operatively treated knee ligament injuries.

Orally bioavailable benzisothiazolone inhibitors of human leukocyte elastase.

Human leukocyte elastase (HLE) has been proposed as a primary mediator of pulmonary emphysema and other inflammatory airway diseases. HLE is capable of cleaving many proteins, including elastin, other components of connective tissue, certain complement proteins, and receptors. Under normal conditions an appropriate balance exists in the lung between HLE and endogenous inhibitors, which scavenge the released enzyme before it exerts deleterious effects in the lung. Emphysema is thought to result from an imbalance in the lung between HLE and endogenous inhibitor (elevated elastase or insufficient inhibitor) that leads to the destruction of alveoli. We have identified WIN 64733 (2) and WIN 63759 (3) as potent (Ki* = 14 and 13 pM, respectively), selective, mechanism-based inhibitors of HLE which are orally bioavailable in the dog (absolute bioavailability 46% and 21%, respectively). In this series the in vitro stabilities of the inhibitors in blood, jejunal homogenates, and liver S9 homogenates are useful predictors of oral bioavailability. After being administered orally (30 mg/kg) to dogs, compounds 2 and 3 are found in the lung, being detected in the epithelial lining fluid obtained by bronchoalveolar lavage (Cmax of 2.5 and 0.47 microgram/mL, respectively).

Determination of etoposide in blood by liquid chromatography with electrochemical detection.

A liquid chromatographic (LC) method for determination of etoposide in dog blood is described. The technique includes solvent extraction of etoposide using a dichloroethane-hexane mixture and reconstitution of the drug in an aqueous reconstitution solution. The samples are analyzed by reversed-phase LC with electrochemical detection. Validation of the method demonstrated good sensitivity, precision and reproducibility. The method is useful for the study of etoposide pharmacokinetics in the dog.

A method for estimation of extracellular concentration of compounds by microdialysis using urea as an endogenous recovery marker in vitro validation.

A new, practical method called microdialysis has been developed for the estimation of free, unbound drug concentrations in the interstitial fluid. This method is based on the use of urea as an endogenous recovery marker. Urea freely distributes throughout the body water compartment, and its plasma concentration can be used as an accurate measure of its interstitial levels. Microdialysis exploits the relationship between the relative recoveries of urea and the recoveries of an analyte that are established during calibration. The calibration is carried out using different probes, varying perfusion rates, membrane surface areas, temperatures, and tissue models. After obtaining a broad range of recoveries, an empirical mathematical model of the relationship between the recovery of the respective analyte and that of urea is formed. During in vivo experiments, a microdialysis probe is placed into a tissue or fluid of interest, and the urea recovery is monitored by comparing the corresponding dialysate and plasma urea levels. From the calculated urea recoveries, correlation equation, and analyte dialysate concentrations, the extracellular concentration of the unbound analyte in the tissue or fluid can be estimated at any given time point. The purpose of this study is to describe the method of microdialysis and demonstrate its applicability in vitro using two model compounds, theophylline and 3'-azido-3'-deoxythymidine (AZT), in the rat plasma.

Pharmacokinetic measurement of drugs in lung epithelial lining fluid by microdialysis: aminoglycoside antibiotics in rat bronchi.

A novel technique for in vivo intrabronchial pharmacokinetic measurements using microdialysis is described. The technique was applied to the measurement of tobramycin and gentamicin in the anesthetized rat. The concentration versus time profiles of the drugs in the lung epithelial lining fluid (ELF) following intravenous bolus administration were determined. The mean penetration ratios into the ELF were determined and found to be 0.36 +/- 0.06 (mean +/- SEM, n = 5) for gentamicin and 0.56 +/- 0.09 (mean +/- SEM, n = 5) for tobramycin. The findings suggest that the technique can be used for intrabronchial pharmacokinetic measurement of drugs in the lung, either as an extension of the bronchoalveolar lavage technique or as a practical alternative to it.

Liquid chromatographic analysis of a potential polymeric-pendant drug delivery system for peptides. Application of high-performance size-exclusion chromatography, reversed-phase high-performance liquid chromatography and ion chromatography to the evaluation of biodegradable poly[(chloromethoxytrialanine methyl ester)phosphazenes].

A novel water-soluble polymer, poly[(chloromethoxytrialanine methyl ester)phosphazene] (poly-Tame), was characterized and evaluated using high-performance size-exclusion chromatography, gradient reversed-phase high-performance liquid chromatography and ion chromatography. These novel liquid chromatographic methods were validated for application to in vitro biodegradation experiments of poly-Tame in aqueous solutions. Results from method validation experiments are presented.

Influence of indomethacin amphoteric gel on gastric ulcerogenicity and absorption of indomethacin in rats.

Indomethacin is a potent and efficacious antiinflammatory agent. However, a limiting side effect is its ability to cause gastric ulceration. This study was designed to investigate the effects of an amphoteric gel on the gastric ulcerogenicity and pharmacokinetics of indomethacin. Oral administration (5 mg/kg) in a suspension and a gel formulation were compared to an intravenous (iv) formulation of indomethacin in rats. The iv formulation administered to rats produced large severe ulcers in some rats but not in others. In contrast, the oral suspension produced small ulcers in all rats. The difference in toxicities is attributed to a centrally mediated action as a result of high plasma levels of indomethacin following iv administration, compared to locally mediated action with the suspension, resulting from local high concentrations of indomethacin on the apical epithelial surface because of the presence of indomethacin crystals. Oral administration of the gel formulation did not result in any gastric ulceration and improved the bioavailability of indomethacin to 115.5%, compared with 68.2% for the suspension. The reduced gastrointestinal toxicity of indomethacin in the gel was attributed to the gel's ability to dissolve indomethacin, preventing the localized high concentration observed with the suspension and possibly providing a gastric protectant phospholipid. The gel formulation doubled the oral bioavailability and the tmax of indomethacin compared to the suspension but did not affect the half-life. The results indicate that the local irritant effect of indomethacin, in rats, can be reduced by appropriate formulation design and suggest that the ulcerogenicity index for indomethacin can be improved by the use of an amphoteric gel formulation.

Automated stability-indicating high-performance liquid chromatographic assay for ethinyl estradiol and (levo)norgestrel tablets.

An automated high-performance liquid chromatography (HPLC) assay for ethinyl estradiol and norgestrel or levonorgestrel in oral contraceptive tablets was developed. Tablets were prepared for on-line injection using a solid sampler and segmented continuous flow techniques. The active components were separated from tablet excipients, impurities, and degradation products on reversed-phase C8 and C18 columns by elution with water-acetonitrile-methanol (45:35:15). A UV detector connected in series with a fluorometric detector measured the UV absorbance of levonorgestrel and norgestrel at 240 nm and the fluorescence of ethinyl estradiol at 310 nm (excitation at 210 nm). The method employed computer control of the injection system and solid sampler for synchronization of the chromatographic and segmented flow streams. The method is applicable for content uniformity and stability testing at a rate of eight samples per hour.

[Mediolateral quadriceps imbalance and peripatellar pain syndrome]. / Mediolaterale Quadrizepsdysbalance und peripatellares Schmerzsyndrom.

In cases of spontaneously occurring patellar pain, there is generally some slight damage to the nerve roots and anterior horn cells of segments L3 and L4. Divergent patellar movement can be measured roentgenologically. When the quadriceps is contracted the patella normally medialward in varus joints, and lateralward in valgus joints and when the leg position is axially correct. In peripatellar pain syndrome, however, lateral movement can be demonstrated in varus joints. Additionally, there is a tendency for the rotation of the patella to depend on the innervation disorder. The discrepancy between the muscular guidance of the patella and the performed guide bed may be one of the factors causing patellar pain. Etiologically, axial malpositions of the leg appear to be important predisposing factors and innervation disorders of the quadriceps muscle realization factors.

[Electromyographic and neurologic findings in radiologically demonstrated numerical variations in the lumbosacral transition]. / Elektromyographische und neurologische Befunde bei radiologisch objektivierten numerischen Variationen im lumbosakralen Ubergang.

Discussions have been going on since the publications of Bertolotti (1917) and Blumensaat and Clasing (1932) as to whether variations in the lumbosacral region and vertebral anomalies, which may alter the statics of the vertebral column, result in typical neurological disorders. Lange and Hipp (1962) found prolapses of lumbar disks localised in the segment above a unilateral or complete assimilation. As they lacked the possibility of an electromyographical examination, they had difficulties in correlating clinical and radiological findings. Neurological, electromyographical and radiological analysis of 20 patients (2 sacralisations, 6 unilateral assimilations, and 12 cases of lumbalisation) revealed: good correlation between clinical and electromyographical findings. In six cases only clinical and electromyographical findings were on the same side and at the same height as the myelographically identified prolapses. Clinical and electromyographical findings did not show significant differences as to the kind of variation, or to the side of the assimilation In sacralisations the prolapses were localised in the 4th lumbar segment, that is, immediately above the variation. In unilateral assimilated vertebrae, disk prolapses were found in two cases in the 4th segment and in 4 cases in the 5th lumbar segment. In three cases prolapse and assimilation were on the same side, in three cases the localisation was median. Patients with lumbalisations had prolapses in seven cases in the 4th, and in four cases in the 5th lumbar segment.(ABSTRACT TRUNCATED AT 250 WORDS)

[Innervation disturbances of the quadriceps muscle in chondropathia patellae. A critical appraisal of the current concept of chondropathia]. / Innervationsstörungen des Musculus quadriceps bei Chondropathia patellae. Eine kritische Revision des gültigen Chondropathia-Konzeptes.

In a group of patients with typical histories of chondropathy, but in whom no other criteria of selection were applied, evidence of neurogenic damage in the quadriceps muscle was found. Innervational damage was also found regularly in the corresponding segments of the paravertebral musculature. Only in three cases, in which horn cell damage was suspected, were there no changes in the paravertebral musculature. There were abnormal structural or functional findings in the lumbar spine in all the patients. A disequilibrium between the median and lateral vastus groups, attributable to innervation, was postulated and subsequently confirmed by electromyography. The nature of chondropathia patellae as an insertion tendopathy is discussed, taking the lack of concomitance of chondropathy and chondromalacia into consideration as well as the findings in the group of patients examined. Phenomena associated with chondropathy which have hitherto incongruous may be explained on the basis of an asymmetrical innervation disturbance.

[Neurologic component and resulting therapeutic concept of patellar chondropathy and chondromalacia]. / Neurologische Komponente und resultierendes therapeutisches Konzept der Chondropathia und Chondromalacia patellae.

Observations of nerve root lesions in spontaneous peripatellar pain led to new aspects concerning the etiology of periarticular pain and chondromalacia patellae. We regard the spontaneous peripatellar pain as an enthesiopathia resulting from an innervation disorder. We believe that also chondromalacia can be caused by nerve root lesions. As a consequence, a change in conservative and operative management is necessary. The aim is a balanced gliding and rotational stability of the patella. This means a muscular compensation of the weakened muscle part and stabilisation of the lumbar and hip region. Surgical techniques should only be applied to normalize the gliding of the patella. There is no indication for ventralisation of tuberositas tibiae.

Multiple-scattering noise in single-mode fibers.

An optical signal transmitted through a single-mode fiber becomes noisy because of varying interferences, which are caused by multiple scattering or reflections, if the fiber temperature or the light frequency is changed. The power and the frequency spectra of this noise are derived.

Stress-induced single-polarization single-mode fiber.

The stress-induced birefringence in a single-mode optical fiber with an elliptical inner cladding or an elliptical core is calculated. Then the design of a fiber is proposed in which only one linearly polarized mode can propagate.