Aluminum and ABC transporter activity

Aluminum is the third most common element on Earth´s crust and despite its wide use in our workaday life it has been associated with several health risks after overexposure. In the present study the impact of aluminum salts upon ABC transporter activity was studied in the P-GP-expressing human blood-brain barrier cell line hCMEC/D3, in MDCKII cells overexpressing BCRP and MRP2, respectively, and in freshly isolated, functionally intact kidney tubules from Atlantic killifish (Fundulus heteroclitus), which express the analog ABC transporters, P-gp, Bcrp and Mrp2. In contrast to previous findings with heavy metals salts (cadmium(II) chloride or mercury(II) chloride), which have a strong inhibitory effect on ABC transporter activity, or zinc(II) chloride and sodium arsenite, which have a stimulatory effect upon ABC transport function, the results indicate no modulatory effect of aluminum salts on the efflux activity of the human ABC transporters P-GP, BCRP and MRP2 nor on the analog transporters P-gp, Bcrp and Mrp2.

Sodium arsenite but not aluminum chloride stimulates ABC transporter activity in renal proximal tubules of killifish (Fundulus heteroclitus)

ABC export proteins including Multidrug resistance-related protein 2 (Mrp2) serve as detoxification mechanism in renal proximal tubules due to active transport of xenobiotics and metabolic waste products into primary urine. The environmental pollutants aluminum and arsenic interfere with a multitude of regulatory mechanisms in the body and here their impact on ABC transporter function was studied. NaAsO₂ but not AlCl₃ rapidly stimulated Mrp2-mediated Texas Red (TR) transport in isolated renal proximal tubules from killifish, a well-established laboratory model for the determination of efflux transporter activity by utilizing fluorescent substrates for the ABC transporters of interest and confocal microscopy followed by image analysis. This observed stimulation remained unaffected by the translation inhibitor cycloheximide (CHX), but it was abrogated by antagonists and inhibitors of the endothelin receptor type B (ET_B)/nitric oxide synthase (NOS)/protein kinase C (PKC) signaling pathway. NaAsO₂-triggered effects were abolished as a consequence of PKCα inhibition through Gö6976 and PKCα inhibitor peptide C2-4. Phosphatidylinositol 3-kinase (PI3K) inhibitor LY 294,002 as well as the mammalian target of rapamycin (mTOR) inhibitor rapamycin suppressed NaAsO₂-triggered stimulation of luminal TR transport. In addition, the stimulatory effect of NaAsO₂ was abolished by GSK650394, an inhibitor of serum- and glucocorticoid-inducible kinase 1 (SGK1), which is an important downstream target. Environmentally relevant concentrations of NaAsO₂ further stimulated transport function of P-glycoprotein (P-gp), Multidrug resistance-related protein 4 (Mrp4) and Breast cancer resistance protein (Bcrp) while AlCl₃ was ineffective. To our knowledge, this is the first report engaging in the impact of NaAsO₂ on efflux transporter signaling and it may contribute to the understanding of defense mechanisms versus this worrying pollutant.

Analytical Challenges Assessing Protein Aggregation and Fragmentation Under Physiologic Conditions

Therapeutic proteins are administered by injection or infusion. After administration, the physiologic environment in the desired body compartment - fluid or tissue - can impact protein stability and lead to changes in the safety and/or efficacy profile. For example, protein aggregation and fragmentation are critical quality attributes of the drug product and can occur after administration to patients. In this context, the in vivo stability of therapeutic proteins has gained increasing attention. However, in vivo protein aggregation and fragmentation are difficult to assess and have been rarely investigated. This mini-review summarizes analytical approaches to assess the stability of therapeutic proteins using simulated physiologic conditions. Furthermore, we discuss factors potentially causing in vivo protein aggregation, precipitation, and fragmentation in complex biological fluids. Different analytical approaches are evaluated with respect to their applicability and possible shortcomings when it comes to these degradation events in biological fluids. Tracking protein stability in biological fluids typically requires purifying or labeling the protein of interest to circumvent matrix interference of biological fluids. Improved analytical methods are strongly needed to gain knowledge on in vivo protein aggregation and fragmentation. In vitro models can support the selection of lead candidates and accelerate the pre-clinical development of therapeutic proteins.

Stability of monoclonal antibodies after simulated subcutaneous administration

Changes in the environment from the drug product to the human physiology might lead to physical and/or chemical modifications of the protein drug, such as in vivo aggregation and fragmentation. Although subcutaneous (SC) injection is a common route of administration for therapeutic proteins, knowledge on in vivo stability in the SC tissue is limited. In this study, we developed a physiologic in vitro model simulating the SC environment in patients. We assessed the stability of two monoclonal antibodies (mAbs) in four different protein-free fluids under physiologic conditions. We monitored protein stability over two weeks using a range of analytical methods, in analogy to testing purposes of a drug product. Both mAbs showed an increase of protein aggregates, fragments, and acidic species. mAb1 was consistently more stable in this in vitro model than mAb2, highlighting the importance of comparing the stability of different mAbs under physiologic conditions. Throughout the study, both mAbs were substantially less stable in bicarbonate buffers as compared to phosphate-buffered saline. In summary, our developed model was able to differentiate stability between molecules. Bicarbonate buffers were more suitable compared to phosphate-buffered saline in regards to simulating the in vivo conditions and evaluating protein liabilities.

Assessing Particle Formation of Biotherapeutics in Biological Fluids

The stability of therapeutic proteins can be impacted in vivo after administration, which may affect patient safety or treatment efficacy, or both. Stability testing of therapeutic proteins using models representing physiologic conditions may guide preclinical development strategy; however, to date only a few studies assessing the physical stability are available in the public domain. In this manuscript, the stability of seven fluorescently labeled monoclonal antibodies (mAbs) was evaluated in human serum and phosphate-buffered saline, two models often discussed to be representative of the situation in humans after intravenous administration. Subvisible particles were analyzed using light obscuration, flow imaging, and imaging flow cytometry. All methods showed that serum itself formed particles under in vitro conditions. Imaging flow cytometry demonstrated that mean particle size and counts of mAbs increased substantially in serum over five days; however, particle formation in phosphate-buffered saline was comparably low. Stability differences were observed across the mAbs evaluated, and imaging flow cytometry data indicated that fluorescently labeled mAbs primarily interacted with serum components. The results indicate that serum may be more suitable as in vitro model to simulate physiologic intravenous conditions in patients closely and evaluate the in vivo stability of therapeutic proteins. Fluorescence labeling and detection methods may be applied to differentiate particles containing therapeutic protein from high amounts of serum particles that form over time.

Assessment of Sensor Concepts for 100% In-Process Control of Low-Volume Aseptic Fill-Finish Processes

The pharmaceutical industry is currently being confronted with new and complex challenges regarding the aseptic filling of parenterals, especially monoclonal antibodies, particularly for fill volumes <200 µL, which have become increasingly important with the increasing and continued development of intravitreal drugs and highly concentrated formulations. Not only does low-volume filling pose challenges to aseptic manufacturing, but the development of suitable in-process control to ensure reliable and robust filling processes for low-volume conditions has also been difficult. In particular, fill volumes <200 µL exceed limits of accuracy and robustness for the well-established method of gravimetric fill-volume control. Therefore, the present study aimed to evaluate and test novel sensors, which may allow the accurate and precise 100% contact-free measurement of drug-product formulations, with respect to filling volumes. These sensors were designed to be less influenced by inevitable noise factors, such as unidirectional airflow and vibrations. We designed the study using five different sensor concepts, to screen and identify suitable alternatives to gravimetric fill-volume control. The examined sensor concepts were based on airflow, capacitive pressure, light obscuration. and capacitive measurements. Our results demonstrated that all of the tested sensor types worked in the desired low-volume range of 10-150 µL and showed remarkable results, in terms of accuracy and precision, when compared with a high-precision gravimetric balance. A sensor based on capacitance measurement was identified as the most promising candidate for future sensor implementation into an aseptic filling line. This sensor design proved to be superior in terms of both sensitivity and precision compared with the other tested sensors. We concluded that this technology may allow the pharmaceutical industry to overcome existing challenges with respect to the reliable measurement of aseptic fill volumes <200 µL. This technology has the potential to fundamentally change how the pharmaceutical industry verifies fill volumes by facilitating 100% in-process control, even at high machine speeds.

Low-Volume Aseptic Filling Using a Linear Peristaltic Pump

The pharmaceutical industry has been confronted with new and complex challenges, particularly with regard to the aseptic filling of parenterals, including monoclonal antibodies and ophthalmologic drugs designed for intravitreal injections, which often require fill volumes <200 µL. In addition to intravitreal administration, microliter doses may be required for applications using highly concentrated formulations and cell and gene therapies. Many of these therapies have either a narrow or unknown therapeutic window, requiring a high degree of accuracy and precision for the filling system. This study aimed to investigate the applicability of a linear peristaltic pump as a novel and innovative filling system for the low-volume filling of parenterals, compared with the state-of-the-art filling systems that are currently used during pharmaceutical production. We characterized the working principle of the pump and evaluated its accuracy for a target fill volume of 50 µL. Our results demonstrated that the linear peristaltic pump can be used for fill volumes ranging from 12 to 420 µL. A deeper investigation was performed with the fill volume of 50 µL, because it represents a typical clinical dose of an intravitreal application. The filling accuracy was stable over an 8 h operation time, with a standard deviation of +/-4.4%. We conclude that this technology may allow the pharmaceutical industry to overcome challenges associated with the reliable filling of volumes <1 mL during aseptic filling. This technology has the potential to change aseptic filling methods by broadening the range of potential fill volumes while maintaining accuracy and precision, even when performing microliter fills.

The use of 4-Hexylresorcinol as antibiotic adjuvant

Ever decreasing efficiency of antibiotic treatment due to growing antibiotic resistance of pathogenic bacteria is a critical issue in clinical practice. The two generally accepted major approaches to this problem are the search for new antibiotics and the development of antibiotic adjuvants to enhance the antimicrobial activity of known compounds. It was therefore the aim of the present study to test whether alkylresorcinols, a class of phenolic lipids, can be used as adjuvants to potentiate the effect of various classes of antibiotics. Alkylresorcinols were combined with 12 clinically used antibiotics. Growth-inhibiting activity against a broad range of pro- and eukaryotic microorganisms was determined. Test organisms did comprise 10 bacterial and 2 fungal collection strains, including E. coli and S. aureus, and clinical isolates of K. pneumoniae. The highest adjuvant activity was observed in the case of 4-hexylresorcinol (4-HR), a natural compound found in plants with antimicrobial activity. 50% of the minimal inhibitory concentration (MIC) of 4-HR caused an up to 50-fold decrease in the MIC of antibiotics of various classes. Application of 4-HR as an adjuvant revealed its efficiency against germination of bacterial dormant forms (spores) and prevented formation of antibiotic-tolerant persister cells. Using an in vivo mouse model of K. pneumoniae-induced sepsis, we could demonstrate that the combination of 4-HR and polymyxin was highly effective. 75% of animals were free of infection after treatment as compared to none of the animals receiving the antibiotic alone. We conclude that alkylresorcinols such as 4-HR can be used as an adjuvant to increase the efficiency of several known antibiotics. We suggest that by this approach the risk for development of genetically determined antibiotic resistance can be minimized due to the multimodal mode of action of 4-HR.

Mechanistic insights into effect of surfactants on oral bioavailability of amorphous solid dispersions

Drug delivery of poorly soluble drugs in form amorphous solid dispersions (ASDs) is an appealing method to increase in vivo bioavailability. For rational formulation design, a mechanistic understanding of the impact of surfactants on the performance of ASD-based formulations is therefore of importance. In this study, we used hot-melt extrusion to prepare ASDs composed of the model drug substance efavirenz with hydroxypropyl methylcellulose phthalate (HPMCP) as the base polymer, and surfactants. Molecular dynamics simulations and in vitro dissolution studies were used to investigate formation and drug release from polymer vesicles, and their ability to maintain a supersaturation state as a function of surfactant composition. It was possible to identify main factors regulating particle formation and to modify dissolution profiles with different excipient compositions. Animal studies in the rat, in combination with physiologically based pharmacokinetic modeling, demonstrated enhanced drug absorption from formed vesicles. The surfactant composition in the ASD had a direct influence on the morphology of these vesicles, as well as kinetics of drug release, and, therefore, the oral bioavailability. ASDs, prepared by hot-melt extrusion method, were optimized for dissolution and adsorption rates increase. Our findings contribute to a better understanding of dissolution behavior of ASDs with respect to the function of surfactants, aiming to facilitate a rational formulation development and an accelerated transition from in vitro systems to in vivo applications.

Excipients for Room Temperature Stable Freeze-Dried Monoclonal Antibody Formulations

Sucrose is a common cryoprotectant and lyoprotectant to stabilize labile biopharmaceuticals during freeze-drying and storage. Sucrose-based formulations require low primary drying temperatures to avoid collapse and monoclonal antibody (mAb) containing products need to be stored refrigerated. The objective of this study is to investigate different excipients enabling storage at room temperature and aggressive, shorter lyophilization cycles. We studied combinations of 2-hydroxypropyl-beta-cyclodextrin (CD), recombinant human albumin, polyvinylpyrroldione (PVP), dextran 40 kDa (Dex), and sucrose (Suc) using 2 mAbs. Samples were characterized for collapse temperature (Tc), glass transition temperature of the liquid (Tg') and freeze-dried formulation (Tg), cake appearance, residual moisture, and reconstitution time. Freeze-dried formulations were stored at 5°C, 25°C, and 40°C for up to 9 months and mAb stability was analyzed for color, turbidity, visible and sub-visible particles, and monomer content. Formulations with CD/Suc or CD/PVP/Suc were superior to pure Suc formulations for long-term storage at 40°C. When using aggressive freeze-drying cycles, these formulations were characterized by pharmaceutically elegant cakes, short reconstitution times, higher Tg', Tc, and Tg. We conclude that the addition of CD allows for shorter freeze-drying cycles with improved cake appearance and enables storage at room temperature, which might reduce costs of goods substantially.

Be Aggressive! Amorphous Excipients Enabling Single-Step Freeze-Drying of Monoclonal Antibody Formulations

Short freeze-drying cycles for biopharmaceuticals are desirable. Formulations containing an amorphous disaccharide, such as sucrose, are prone to collapse upon aggressive primary drying at higher shelf temperature. We used 2-hydroxypropyl-betacyclodextrin (HPBCD) in combination with sucrose and polyvinylpyrrolidone (PVP) to develop an aggressive lyophilization cycle for low concentration monoclonal antibody (mAb) formulations. Glass transition temperature and collapse temperature of the formulations were determined, and increasingly aggressive cycle parameters were applied. Using a shelf temperature of +30 °C during primary drying, the concept of combining sublimation and desorption of water in a single drying step was investigated. Cake appearance was evaluated visually and by micro-computed tomography. Lyophilisates were further analyzed for reconstitution time, specific surface area, residual moisture, and glass transition temperature. We demonstrated the applicability of single-step freeze-drying, shortening the total cycle time by 50% and providing elegant lyophilisates for pure HPBCD and HPBCD/sucrose formulations. HPBCD/PVP/sucrose showed minor dents, while good mAb stability at 10 mg/mL was obtained for HPBCD/sucrose and HPBCD/PVP/sucrose when stored at 40 °C for 3 months. We conclude that HPBCD-based formulations in combination with sucrose are highly attractive, enabling aggressive, single-step freeze-drying of low concentration mAb formulations, while maintaining elegant lyophilisates and ensuring protein stability at the same time.

The Effect of Formulation, Process, and Method Variables on the Reconstitution Time in Dual Chamber Syringes

Reconstitution time of dried products is influenced by various factors including formulation, process, and reconstitution method itself. This manuscript describes factors affecting reconstitution in a dual chamber syringe using highly concentrated human monoclonal antibody and bovine serum albumin model formulations. Freezing and drying conditions had only minor impact on the reconstitution time, whereas the primary container and thus the geometry of the lyophilization cake played a major role. Prewarmed diluent and agitation decreased reconstitution time. For effective agitation, short displacements and high agitation frequencies were found to be desirable conditions to minimize reconstitution time for a given lyophilization cake while foam formation was minimized. The article also provides general strategies (e.g., reduction of lyophilized cake density, use of an optimized fill finish process, and suitable method parameters) to reduce reconstitution time, especially for drug product presented in a dual chamber syringe configuration.

LAY ABSTRACT

Dried drug products need to be reconstituted to a liquid form before being applied parenteral. Reconstitution time is an important attribute and needs to be as fast as possible in order to serve patients' compliance. Reconstitution time is influenced by various factors including formulation, process, and the reconstitution method itself. The article provides general strategies (e.g., reduction of dried drug product cake density, use of an optimized fill finish process, and suitable method parameters) to reduce reconstitution time, especially for drug product presented in a dual chamber syringe. Fast reconstitution of lyophilisates in dual chamber syringe can be achieved by a combination of optimized manufacturing procedures and clear instructions for the end-user (e.g., roll syringe between palms to warm and agitate it to accelerate reconstitution).

Functionalized calcium carbonate microparticles for the delivery of proteins

The recently introduced functionalized calcium carbonate (FCC), a porous microparticle with a nano-structured, lamellar surface, shows promising properties in the field of oral drug delivery. In this work, FCC was loaded with biomolecules e.g. lysozyme (Lys) and bovine serum albumin (BSA) in order to investigate its suitability to deliver protein based drugs. Loading efficiency for our model proteins was >90% and enzyme activity was preserved as demonstrated by Michaelis-Menten enzyme kinetic experiments. Circular dichroism analysis confirmed, that neither the structure of both model substances, nor the activity of Lys was affected by the loading process or the interaction with the surface of FCC. Electron microscopy (SEM) and mercury porosimetry were indicative of protein deposition on the particle surface as well as within the particle pores. Release properties were investigated in a customized flow cell, which simulates the conditions in the oral cavity. Depending on the isoelectric point of the investigated proteins, complete release was obtained within 1.5h. This work shows, that FCC is a suitable pharmaceutical excipient for delivery of proteins.

A Method To Determine the Kinetics of Solute Mixing in Liquid/Liquid Formulation Dual-Chamber Syringes

Dual-chamber syringes were originally designed to separate a solid substance and its diluent. However, they can also be used to separate liquid formulations of two individual drug products, which cannot be co-formulated due to technical or regulatory issues. A liquid/liquid dual-chamber syringe can be designed to achieve homogenization and mixing of both solutions prior to administration, or it can be used to sequentially inject both solutions. While sequential injection can be easily achieved by a dual-chamber syringe with a bypass located at the needle end of the syringe barrel, mixing of the two fluids may provide more challenges. Within this study, the mixing behavior of surrogate solutions in different dual-chamber syringes is assessed. Furthermore, the influence of parameters such as injection angle, injection speed, agitation, and sample viscosity were studied. It was noted that mixing was poor for the commercial dual-chamber syringes (with a bypass designed as a longitudinal ridge) when the two liquids significantly differ in their physical properties (viscosity, density). However, an optimized dual-chamber syringe design with multiple bypass channels resulted in improved mixing of liquids.

LAY ABSTRACT

Dual-chamber syringes were originally designed to separate a solid substance and its diluent. However, they can also be used to separate liquid formulations of two individual drug products. A liquid/liquid dual-chamber syringe can be designed to achieve homogenization and mixing of both solutions prior to administration, or it can be used to sequentially inject both solutions. While sequential injection can be easily achieved by a dual-chamber syringe with a bypass located at the needle end of the syringe barrel, mixing of the two fluids may provide more challenges. Within this study, the mixing behavior of surrogate solutions in different dual-chamber syringes is assessed. Furthermore, the influence of parameters such as injection angle, injection speed, agitation, and sample viscosity were studied. It was noted that mixing was poor for the commercially available dual-chamber syringes when the two liquids significantly differ in viscosity and density. However, an optimized dual-chamber syringe design resulted in improved mixing of liquids.

The Pharmaceutical Capping Process-Correlation between Residual Seal Force, Torque Moment, and Flip-off Removal Force

The majority of parenteral drug products are manufactured in glass vials with an elastomeric rubber stopper and a crimp cap. The vial sealing process is a critical process step during fill-and-finish operations, as it defines the seal quality of the final product. Different critical capping process parameters can affect rubber stopper defects, rubber stopper compression, container closure integrity, and also crimp cap quality. A sufficiently high force to remove the flip-off button prior to usage is required to ensure quality of the drug product unit by the flip-off button during storage, transportation, and until opening and use. Therefore, the final product is 100% visually inspected for lose or defective crimp caps, which is subjective as well as time- and labor-intensive. In this study, we sealed several container closure system configurations with different capping equipment settings (with corresponding residual seal force values) to investigate the torque moment required to turn the crimp cap. A correlation between torque moment and residual seal force has been established. The torque moment was found to be influenced by several parameters, including diameter of the vial head, type of rubber stopper (serum or lyophilized) and type of crimp cap (West(®) or Datwyler(®)). In addition, we measured the force required to remove the flip-off button of a sealed container closure system. The capping process had no influence on measured forces; however, it was possible to detect partially crimped vials. In conclusion, a controlled capping process with a defined target residual seal force range leads to a tight crimp cap on a sealed container closure system and can ensure product quality.

LAY ABSTRACT

The majority of parenteral drug products are manufactured in a glass vials with an elastomeric rubber stopper and a crimp cap. The vial sealing process is a critical process step during fill-and-finish operations, as it defines the seal quality of the final product. An adequate force to remove the flip-off button prior to usage is required to ensure product quality during storage and transportation until use. In addition, the complete crimp cap needs to be fixed in a tight position on the vial. In this study, we investigated the torque moment required to turn the crimp cap and the force required to remove the flip-off button of container closure system sealed with different capping equipment process parameters (having different residual seal force values).

Impact of Vial Capping on Residual Seal Force and Container Closure Integrity

The vial capping process is a critical unit operation during drug product manufacturing, as it could possibly generate cosmetic defects or even affect container closure integrity. Yet there is significant variability in capping equipment and processes, and their relation to potential defects or container closure integrity has not been thoroughly studied. In this study we applied several methods-residual seal force tester, a self-developed system of a piezo force sensor measurement, and computed tomography-to characterize different container closure system combinations that had been sealed using different capping process parameter settings. Additionally, container closure integrity of these samples was measured using helium leakage (physical container closure integrity) and compared to characterization data. The different capping equipment settings lead to residual seal force values from 7 to 115 N. High residual seal force values were achieved with high capping pre-compression force and a short distance between the capping plate and plunge. The choice of container closure system influenced the obtained residual seal force values. The residual seal force tester and piezoelectric measurements showed similar trends. All vials passed physical container closure integrity testing, and no stopper rupture was seen with any of the settings applied, suggesting that container closure integrity was warranted for the studied container closure system with the chosen capping setting ranges.

LAY ABSTRACT

The vial capping process is a critical unit operation during drug product manufacturing, as it could possibly generate cosmetic defects or even affect container closure integrity. Yet there is significant variability in capping equipment and processes, and their relation to potential defects or container closure integrity has not been thoroughly studied. In this study we applied several methods-residual seal force tester, a self-developed system of a piezo force sensor measurement, and computed tomography-to characterize different container closure system combinations that had been sealed using different capping process parameter settings. The residual seal force tester can analyze a variety of different container closure systems independent of the capping equipment. An adequate and safe residual seal force range for each container closure system configuration can be established with the residual seal force tester and additional methods like computed tomography scans and leak testing. In the residual seal force range studied, the physical container closure integrity of the container closure system was warranted.

New Processes for Freeze-Drying in Dual-Chamber Systems

Dual-chamber systems can offer self-administration and home care use for lyophilized biologics. Only a few products have been launched in dual-chamber systems so far-presumably due to dual-chamber systems' complex and costly drug product manufacturing process. Within this paper, two improved processes (both based on tray filling technology) for freeze-drying pharmaceuticals in dual-chamber systems are described. Challenges with regards to heat transfer were tackled by (1) performing the freeze-drying step in a needle-down orientation in combination with an aluminum block, or (2) freeze-drying the drug product "externally" in a metal cartridge with subsequent filling of the lyophilized cake into the dual-chamber system. Metal-mediated heat transfer was shown to be efficient in both cases and batch (unit-to-unit) homogeneity with regards to sublimation rate was increased. It was difficult to influence ice crystal size using different methods when in use with an aluminum block due to its heat capacity. Using such a metal carrier implies a large heat capacity leading to relatively small ice crystals. Compared to the established process, drying times were reduced by half using the new processes. The drying time was, however, longer for syringes compared to vials due to the syringe design (long and slim). The differences in drying times were less pronounced for aggressive drying cycles. The proposed processes may help to considerably decrease investment costs into dual-chamber system fill-finish equipment.

LAY ABSTRACT

Dual-chamber syringes offer self-administration and home care use for freeze-dried pharmaceuticals. Only a few products have been launched in dual-chamber syringes so far-presumably due to their complex and costly drug product manufacturing process. In this paper two improved processes for freeze-drying pharmaceuticals in dual-chamber syringes are described. The major challenge of freeze-drying is to transfer heat through a vacuum. The proposed processes cope with this challenge by (1) freeze-drying the drug product in the syringe in an orientation in which the product is closest to the heat source, or (2) freeze-drying the drug product outside the syringe in a metal tube. The latter requires filling the freeze-dried product subsequently into the dual-chamber syringe. Both processes were very efficient and promised to achieve similar freeze-drying conditions for all dual-chamber syringes within one production run. The proposed processes may help to considerably decrease investment costs into dual-chamber syringe fill-finish equipment.

Influence of Different Container Closure Systems and Capping Process Parameters on Product Quality and Container Closure Integrity (CCI) in GMP Drug Product Manufacturing

Capping equipment used in good manufacturing practice manufacturing features different designs and a variety of adjustable process parameters. The overall capping result is a complex interplay of the different capping process parameters and is insufficiently described in literature. It remains poorly studied how the different capping equipment designs and capping equipment process parameters (e.g., pre-compression force, capping plate height, turntable rotating speed) contribute to the final residual seal force of a sealed container closure system and its relation to container closure integrity and other drug product quality parameters. Stopper compression measured by computer tomography correlated to residual seal force measurements.In our studies, we used different container closure system configurations from different good manufacturing practice drug product fill & finish facilities to investigate the influence of differences in primary packaging, that is, vial size and rubber stopper design on the capping process and the capped drug product. In addition, we compared two large-scale good manufacturing practice manufacturing capping equipment and different capping equipment settings and their impact on product quality and integrity, as determined by residual seal force.The capping plate to plunger distance had a major influence on the obtained residual seal force values of a sealed vial, whereas the capping pre-compression force and the turntable rotation speed showed only a minor influence on the residual seal force of a sealed vial. Capping process parameters could not easily be transferred from capping equipment of different manufacturers. However, the residual seal force tester did provide a valuable tool to compare capping performance of different capping equipment. No vial showed any leakage greater than 10(-8)mbar L/s as measured by a helium mass spectrometry system, suggesting that container closure integrity was warranted in the residual seal force range tested for the tested container closure systems.

LAY ABSTRACT

Capping equipment used in good manufacturing practice manufacturing features different designs and a variety of adjustable process parameters. The overall capping result is a complex interplay of the different capping process parameters and is insufficiently described in the literature. It remains poorly studied how the different capping equipment designs and capping equipment process parameters contribute to the final capping result.In this study, we used different container closure system configurations from different good manufacturing process drug product fill & finish facilities to investigate the influence of the vial size and the rubber stopper design on the capping process. In addition, we compared two examples of large-scale good manufacturing process capping equipment and different capping equipment settings and their impact on product quality and integrity, as determined by residual seal force.

Technology, Applications, and Process Challenges of Dual Chamber Systems

Dual-chamber systems provide an option as a drug and device combination product, when home care and emergency lyophilized products are intended. Nevertheless, until today, there are only a few products on the market, due to the challenges and limitations in manufacturability, product formulation, and product stability in a dual-chamber configuration, as well as economic considerations. This review serves to describe currently available dual-chamber systems and to discuss factors to be considered for appropriate selection and establishing fill-finish processes.

The pharmaceutical vial capping process: Container closure systems, capping equipment, regulatory framework, and seal quality tests

Parenteral drug products are protected by appropriate primary packaging to protect against environmental factors, including potential microbial contamination during shelf life duration. The most commonly used CCS configuration for parenteral drug products is the glass vial, sealed with a rubber stopper and an aluminum crimp cap. In combination with an adequately designed and controlled aseptic fill/finish processes, a well-designed and characterized capping process is indispensable to ensure product quality and integrity and to minimize rejections during the manufacturing process. In this review, the health authority requirements and expectations related to container closure system quality and container closure integrity are summarized. The pharmaceutical vial, the rubber stopper, and the crimp cap are described. Different capping techniques are critically compared: The most common capping equipment with a rotating capping plate produces the lowest amount of particle. The strength and challenges of methods to control the capping process are discussed. The residual seal force method can characterize the capping process independent of the used capping equipment or CCS. We analyze the root causes of several cosmetic defects associated with the vial capping process.

Pharmacological characterization of designer cathinones in vitro

BACKGROUND AND PURPOSE

Designer β-keto amphetamines (e.g. cathinones, 'bath salts' and 'research chemicals') have become popular recreational drugs, but their pharmacology is poorly characterized.

EXPERIMENTAL APPROACH

We determined the potencies of cathinones to inhibit DA, NA and 5-HT transport into transporter-transfected HEK 293 cells, DA and 5-HT efflux from monoamine-preloaded cells, and monoamine receptor binding affinity.

KEY RESULTS

Mephedrone, methylone, ethylone, butylone and naphyrone acted as non-selective monoamine uptake inhibitors, similar to cocaine. Mephedrone, methylone, ethylone and butylone also induced the release of 5-HT, similar to 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) and other entactogens. Cathinone, methcathinone and flephedrone, similar to amphetamine and methamphetamine, acted as preferential DA and NA uptake inhibitors and induced the release of DA. Pyrovalerone and 3,4-methylenedioxypyrovalerone (MDPV) were highly potent and selective DA and NA transporter inhibitors but unlike amphetamines did not evoke the release of monoamines. The non-β-keto amphetamines are trace amine-associated receptor 1 ligands, whereas the cathinones are not. All the cathinones showed high blood-brain barrier permeability in an in vitro model; mephedrone and MDPV exhibited particularly high permeability.

CONCLUSIONS AND IMPLICATIONS

Cathinones have considerable pharmacological differences that form the basis of their suggested classification into three groups. The predominant action of all cathinones on the DA transporter is probably associated with a considerable risk of addiction.

The norepinephrine transporter inhibitor reboxetine reduces stimulant effects of MDMA ("ecstasy") in humans

This study assessed the pharmacodynamic and pharmacokinetic effects of the interaction between the selective norepinephrine (NE) transporter inhibitor reboxetine and 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") in 16 healthy subjects. The study used a double-blind, placebo-controlled crossover design. Reboxetine reduced the effects of MDMA including elevations in plasma levels of NE, increases in blood pressure and heart rate, subjective drug high, stimulation, and emotional excitation. These effects were evident despite an increase in the concentrations of MDMA and its active metabolite 3,4-methylenedioxyamphetamine (MDA) in plasma. The results demonstrate that transporter-mediated NE release has a critical role in the cardiovascular and stimulant-like effects of MDMA in humans.

Discovery of carmegliptin: a potent and long-acting dipeptidyl peptidase IV inhibitor for the treatment of type 2 diabetes

Design, synthesis, and SAR are described for a class of DPP-IV inhibitors based on aminobenzo[a]quinolizines with non-aromatic substituents in the S1 specificity pocket. One representative thereof, carmegliptin (8p), was chosen for clinical development. Its X-ray structure in complex with the enzyme and early efficacy data in animal models of type 2 diabetes are also presented.

Characterization of (R,S)-5,7-di-tert-butyl-3-hydroxy-3-trifluoromethyl-3H-benzofuran-2-one as a positive allosteric modulator of GABAB receptors

BACKGROUND AND PURPOSE

As baclofen is active in patients with anxiety disorders, GABAB receptors have been implicated in the modulation of anxiety. To avoid the side effects of baclofen, allosteric enhancers of GABAB receptors have been studied to provide an alternative therapeutic avenue for modulation of GABAB receptors. The aim of this study was to characterize derivatives of (R,S)-5,7-di-tert-butyl-3-hydroxy-3-trifluoromethyl-3H-benzofuran-2-one (rac-BHFF) as enhancers of GABAB receptors.

EXPERIMENTAL APPROACH

Enhancing properties of rac-BHFF were assessed in the Chinese hamster ovary (CHO)-Galpha16-hGABA(B1a,2a) cells by Fluorometric Imaging Plate Reader and GTPgamma[35S]-binding assays, and in rat hippocampal slices by population spike (PS) recordings. In vivo activities of rac-BHFF were assessed using the loss of righting reflex (LRR) and stress-induced hyperthermia (SIH) models.

KEY RESULTS

In GTPgamma[35S]-binding assays, 0.3 microM rac-BHFF or its pure enantiomer (+)-BHFF shifted the GABA concentration-response curve to the left, an effect that resulted in a large increase in both GABA potency (by 15.3- and 87.3-fold) and efficacy (149% and 181%), respectively. In hippocampal slices, rac-BHFF enhanced baclofen-induced inhibition of PS of CA1 pyramidal cells. In an in vivo mechanism-based model in mice, rac-BHFF increased dose-dependently the LRR induced by baclofen with a minimum effective dose of 3 mg kg(-1) p.o. rac-BHFF (100 mg kg(-1) p.o.) tested alone had no effect on LRR nor on spontaneous locomotor activity, but exhibited anxiolytic-like activity in the SIH model in mice.

CONCLUSIONS AND IMPLICATIONS

rac-BHFF derivatives may serve as valuable pharmacological tools to elucidate the pathophysiological roles played by GABAB receptors in the central and peripheral nervous systems.

Evaluation of the NR2B-selective NMDA receptor antagonist Ro 63-1908 on rodent behaviour: evidence for an involvement of NR2B NMDA receptors in response inhibition

We have characterised the effects of the recently described NMDA NR2B subtype selective antagonist, Ro 63-1908, on spontaneous behaviour and in tasks sensitive to non-selective NMDA antagonists. In both rats and wild type mice, Ro 63-1908 (1-30mg/kg sc) produced a mild increase in motor activity of lesser magnitude than that elicited by dizocilpine. No signs of overt PCP-like stereotypy were seen in either species at equivalent doses. PPI was also unaffected. However, in mice lacking the NR2A subunit, Ro 63-1908 (3-30mg/kg) produced a profound hyperactivity of similar magnitude to dizocilpine but few other 'PCP-like' behaviours. In rats, Ro 63-1908 (1-10mg/kg) did not affect Morris water maze or delayed matching performance. In a 5-choice serial reaction time task, requiring rats to respond to a visual stimulus presented after a fixed time interval, Ro 63-1908 (0.3-3mg/kg) produced a dramatic increase in premature responses - accuracy was relatively unaffected. Finally in a DRL24 task, Ro 63-1908 (0.3-3mg/kg) reduced inter-response time, increased response rate, and consequently reduced efficiency. We conclude that the improved profile of Ro 63-1908 compared to NMDA channel blockers is due to both its selectivity for the NR2B vs. NR2A subunit containing receptors and its activity-dependent mechanism of action. However, in the 5-CSRT and DRL24 tasks, Ro 63-1908 produced behaviours suggestive of impaired response inhibition, implicating a critical role of NMDA NR2B transmission in this process.

Uptake of cationzied albumin coupled liposomes by cultured porcine brain microvessel endothelial cells and intact brain capillaries

The suitability of protein-coupled liposomes as drug carriers for brain specific targeting was investigated using albumin (BSA) and cationized albumin (CBSA), respectively, as model proteins. Liposomes coated with polyethylene glycol (sterically stabilized, PEG-liposomes) were prepared from phosphatidylcholine, cholesterol, and a PEG-derivatized phospholipid and covalently coupled to thiolated BSA or CBSA. Liposomes were loaded with carboxy-fluorescein and rhodamine-labeled dipalmitoyl-phosphatidylethanolamine as hydrophilic and lipophilic marker compounds, respectively. The interaction of these constructs with monolayers of porcine brain capillary endothelial cells (BCEC) and freshly isolated porcine brain capillaries was studied by means of fluorescence assays and confocal laser scanning fluorescence microscopy (CLSFM). In contrast to BSA, CBSA was rapidly taken up by cultured BCECs. BSA-coupled liposomes did not interact with endothelial cells, whereas CBSA-coupled liposomes bound to cellular surfaces and exhibited time dependently a high intracellular accumulation. CBSA-conjugated liposomes were also taken up by intact brain capillaries. Cellular uptake could be inhibited by free cationized albumin, phenylarsineoxide, nocodazole, and filipin, but not by dansylcadaverine, suggesting a caveolae-mediated incorporation process. Immunostaining demonstrated a high expression of caveolin in the capillary endothelium. In conclusion, liposomes coupled to CBSA are taken up into brain endothelium via an endocytotic pathway and may therefore be a suitable carrier for drug delivery to the brain.

Endocytosis and transcytosis of an immunoliposome-based brain drug delivery system

Immunoliposomes conjugated with the OX26 monoclonal antibody to the rat transferrin receptor can be used for brain delivery of small molecules. In the present study the uptake of OX26-immunoliposomes by target cells as well as their transcytosis across the blood-brain barrier was investigated. Microscopy of RG2 rat glioma cells incubated with fluorescence labeled OX26-immunoliposomes revealed intracellular co-localization of liposomal cargo, the liposomal membrane bilayer and the OX26 monoclonal antibody. The distinct particulate staining pattern was indicative for accumulation of OX26-immunoliposomes within endosomal or lysosomal compartments. Prolonged incubations demonstrated endosomal release of the liposomal cargo propidium iodide to the cytoplasm. A maximum of 50% of propidium iodide was released from the endosomal compartment after 24 hours of incubation. Transcytosis was studied using an in vitro model of the blood-brain barrier consisting of immortalized RBE4 rat brain endothelial cells. OX26-immunoliposomes did permeate across the RBE4 cell monolayer and showed a permeability coefficient of P(app) = 1.6 x 10(-5) ml/s. Transport was inhibited at low temperature, by competition with free OX26 or by exchanging the OX26 monoclonal antibody for an unspecific isotype antibody. Transcytosis of OX26-immunolipsomes was confirmed in vivo by the brain perfusion and capillary depletion technique. OX26-immunoliposomes were detected within the post-vascular compartment of brain parenchyma (PS product = 2.4 microl/g/min.) and were not associated with the brain microvasculature.

Evidence that nicotinic alpha(7) receptors are not involved in the hyperlocomotor and rewarding effects of nicotine

Neuronal nicotinic receptors are comprised of combinations of alpha(2-9) and beta(2-4) subunits arranged to form a pentameric receptor. Currently, the principal central nervous system (CNS) subtypes are believed to be alpha(4)beta(2) and a homomeric alpha(7) receptor, although other combinations almost certainly exist. The identity of the nicotinic receptor subtype(s) involved in the rewarding effects of nicotine are unknown. In the present study, using some recently described subtype selective nicotinic agonists and antagonists, we investigated the role of the alpha(7) nicotinic receptor in the mediation of nicotine-induced hyperactivity and self-administration in rats. The alpha(7) receptor agonists AR-R 17779 and DMAC failed to stimulate locomotor activity in both nicotine-nontolerant and -sensitized rats. In contrast, nicotine and the putative alpha(4)beta(2) subtype selective agonist SIB1765F increased activity in both experimental conditions. In nicotine-sensitized rats, the high affinity (including the alpha(4)beta(2) subtype) nicotinic antagonist dihydro-beta-erythroidine (DHbetaE), but not the selective alpha(7) antagonist methyllycaconitine (MLA), antagonized a nicotine-induced hyperactivity. Similarly, DHbetaE, but not MLA, pretreatment reduced nicotine self-administration. Electrophysiology experiments using Xenopus oocytes expressing the human alpha(7) receptor confirmed AR-R 17779 and DMAC to be potent agonists at this site, and further studies demonstrated the ability of systemically administered AR-R 17779 to penetrate into the CNS. Taken together, these results indicate a negligible role of alpha(7) receptors in nicotine-induced hyperlocomotion and reward in the rat, and support the view for an involvement of a member from the high-affinity nicotinic receptor subclass, possibly alpha(4)beta(2). Issues such as drug potency, CNS penetration, and desensitization of the alpha(7) receptor are discussed.

Modulation of multidrug resistance protein expression in porcine brain capillary endothelial cells in vitro

Multidrug resistance-associated protein (MRP) is a transport system that is involved in the elimination of xenobiotics and biologically active endogenous substrates. Recently, the presence of MRP has been demonstrated in cultured brain capillary endothelial cells (BCECs). The time-dependent, functional expression of MRP in porcine BCECs was investigated to assess the value of this cell culture model for drug transport at the blood-brain barrier. Western blot analysis was used to investigate MRP expression in freshly isolated porcine BCECs and compared to MRP expression at days 8 and 10 in culture. Subcellular localization of MRP was investigated by immunocytochemistry with an MRP-specific monoclonal antibody, MRPr1. Functional activity of MRP was assessed by efflux studies with the fluorescent MRP substrate glutathione-methylfluorescein (GS-MF). No significant MRP expression was detected in freshly isolated endothelial cells. However, MRP expression is up-regulated in cell culture in a time-dependent manner. Immunostaining revealed predominantly perinuclear and, to a lesser degree, plasma membrane localization of MRP. At 10 degrees C GS-MF efflux was significantly decreased, indicating the involvement of an energy-dependent transport system. Efflux of GS-MF was apparently inhibited by MK571, a specific inhibitor for MRP. Porcine BCECs demonstrate up-regulation of functional MRP expression during culture, as observed in human tissue, and therefore might serve as a useful in vitro system for studying MRP-mediated blood-brain barrier transport.

HIV protease inhibitor ritonavir: a more potent inhibitor of P-glycoprotein than the cyclosporine analog SDZ PSC 833

The effect of P-glycoprotein inhibition on the uptake of the HIV type 1 protease inhibitor saquinavir into brain capillary endothelial cells was studied using porcine primary brain capillary endothelial cell monolayers as an in vitro test system. As confirmed by polymerase chain reaction and Western blot analysis, this system functionally expressed class I P-glycoprotein (pgp1A). P-Glycoprotein isoforms pgp1B or pgp1D could not be detected. The uptake of saquinavir into endothelial cells could be described as the result of a diffusional term of uptake and an oppositely directed saturable extrusion process. Net uptake of saquinavir into cultured brain endothelial cells could be increased significantly up to 2-fold by SDZ PSC 833 in a dose-dependent manner, with an IC(50) of 1.13 microM. In addition, the HIV protease inhibitor ritonavir inhibited p-glycoprotein-mediated extrusion of saquinavir with an IC(50) of 0.2 microM, indicating a high affinity of ritonavir for p-glycoprotein. In conclusion, we showed that the HIV protease inhibitor ritonavir is a more potent inhibitor of P-glycoprotein than the multidrug resistance (MDR)-reversing agent SDZ PSC 833. The inclusion of this drug in combination regimens may greatly facilitate brain uptake of HIV protease inhibitors, which is especially important in patients suffering from AIDS dementia complex.