Candidate For Formulation Research Articles

Application of a High-Throughput Relative Chemical Stability Assay to Screen Therapeutic Protein Formulations by Assessment of Conformational Stability and Correlation to Aggregation Propensity

In this study, an automated high-throughput relative chemical stability (RCS) assay was developed in which various therapeutic proteins were assessed to determine stability based on the resistance to denaturation post introduction to a chaotrope titration. Detection mechanisms of both intrinsic fluorescence and near UV circular dichroism (near-UV CD) are demonstrated. Assay robustness was investigated by comparing multiple independent assays and achieving r(2) values >0.95 for curve overlays. The complete reversibility of the assay was demonstrated by intrinsic fluorescence, near-UV CD, and biologic potency. To highlight the method utility, we compared the RCS assay with differential scanning calorimetry and dynamic scanning fluorimetry methodologies. Utilizing C1/2 values obtained from the RCS assay, formulation rank-ordering of 12 different mAb formulations was performed. The prediction of long-term stability on protein aggregation is obtained by demonstrating a good correlation with an r(2) of 0.83 between RCS and empirical aggregation propensity data. RCS promises to be an extremely useful tool to aid in candidate formulation development efforts based on the complete reversibility of the method to allow for multiple assessments without protein loss and the strong correlation between the C1/2 data obtained and accelerated stability under stressed conditions.

Technical Decision-Making with Higher Order Structure Data: Specific Binding of a Nonionic Detergent Perturbs Higher Order Structure of a Therapeutic Monoclonal Antibody

Robust higher order structure (HOS) characterization capability and strategy are critical throughout biopharmaceutical development from initial candidate selection and formulation screening to process optimization and manufacturing. This case study describes the utility of several orthogonal HOS methods as investigational tools during purification process development. An atypically high level of residual detergent in a development drug substance batch of a therapeutic monoclonal antibody triggered a root cause investigation. Several orthogonal biophysical techniques were used to uncover and characterize a specific interaction between the detergent and the antibody. Isothermal titration calorimetry (ITC) was used to quantify the molar ratio and affinity of the binding event, and circular dichroism (CD) spectroscopy and differential scanning calorimetry (DSC) were used to evaluate corresponding impacts on secondary/tertiary structure and thermal stability, respectively. As detergents are used routinely in biopharmaceutical processing, this case study highlights the value and power of HOS data in informing technical investigations and underlines the importance of HOS characterization as a component of overall biopharmaceutical analytical control strategy.

Concentrated protein body product derived from rice endosperm as an oral tolerogen for allergen-specific immunotherapy--a new mucosal vaccine formulation against Japanese cedar pollen allergy.

The endoplasmic reticulum-derived type-I protein body (PB-I) from rice endosperm cells is an ideal candidate formulation for the oral delivery of bioencapsulated peptides as tolerogens for allergen-specific immunotherapy. In the present study, PBs containing the deconstructed Japanese cedar pollen allergens Cryptomeria japonica 1 (Cry j 1) and Cry j 2 were concentrated by treatment with thermostable α-amylase at 90°C to remove the starch from milled rice powder, which resulted in a 12.5-fold reduction of dry weight compared to the starting material. The modified Cry j 1 and Cry j 2 antigens in this concentrated PB product were more resistant to enzymatic digestion than those in the milled seed powder despite the absence of intact cell wall and starch, and remained stable for at least 10 months at room temperature without detectable loss or degradation. The high resistance of these allergens could be attributed to changes in protein physicochemical properties induced by the high temperature concentration process, as suggested by the decreased solubility of the antigens and seed proteins in PBs in step-wise-extraction experiments. Confocal microscopy showed that the morphology of antigen-containing PB-Is was preserved in the concentrated PB product. The concentrated PB product induced specific immune tolerance against Cry j 1 and Cry j 2 in mice when orally administered, supporting its potential use as a novel oral tolerogen formulation.

Combinatorial optimization of La, Ce-co-doped pyrosilicate phosphors as potential scintillator materials.

A combinatorial method was employed to rapidly screen the effects of La, Ce-co-doping on the luminescent properties of Gd2Si2O7 pyrosilicate using an 8 × 8 library. The candidate formulations (Gd1-x-yLax)2Si2O7:Ce2y were evaluated by luminescence pictures under ultraviolet excitation. The optimal composition was found to be (Gd0.89La0.1)2Si2O7:Ce0.02 after scaled-up preparation and detailed characterization of powder samples, which shows an excellent light output under both ultraviolet and X-ray excitation (about 5.43 times of commercial YAG:Ce powders). The XRD results indicate that the phase structure sequence is tetragonal-orthorhombic-triclinic for different calcination temperatures and doping ions. The (Gd0.89La0.1)2Si2O7:Ce0.02 powder sample also demonstrated excellent temperature stability of luminescence up to 200 °C and a short decay time of several tens of nanoseconds, suggesting that this may represent a new kind of scintillation material, such as single crystals, ceramics, glass, or phosphors.

A Microfluidic Diffusion Cell for Fast and Easy Percutaneous Absorption Assays.

Percutaneous absorption assays of molecules for pharmaceutical and cosmetology purposes are important to determine the bioavailability of new compounds, once topically applied. The current method of choice is to measure the rate of diffusion through excised human skin using a diffusion cell. This method however entails significant drawbacks such as scarce availability and poor reproducibility of the sample, low sampling rate, and tedious assay setup. The objective of the present work is to propose an alternative method that overcomes these issues by integrating an experimental model of the skin (artificial stratum corneum) and online optical sensors into a microfluidic device. The measurement of the diffusion profile followed by the calculation of the permeability coefficients and time lag were performed on seven different molecules and obtained data positively fit with those available from literature on human skin penetration. The coating of the lipid mixture to generate the artificial stratum corneum also proved robust and reproducible. The results show that the proposed device is able to give fast, real-time, accurate, and reproducible data in a user-friendly manner, and can be produced at a large scale. These assets should help both the cosmetics and pharmaceutics fields where the skin is the target or a pathway of a formulated compound, by allowing more candidate molecules or formulations to be assessed during the various stages of their development.

A high-order conservative collocation scheme and its application to global shallow-water equations

Abstract. In this paper, an efficient and conservative collocation method is proposed and used to develop a global shallow-water model. Being a nodal type high-order scheme, the present method solves the pointwise values of dependent variables as the unknowns within each control volume. The solution points are arranged as Gauss–Legendre points to achieve high-order accuracy. The time evolution equations to update the unknowns are derived under the flux reconstruction (FR) framework (Huynh, 2007). Constraint conditions used to build the spatial reconstruction for the flux function include the pointwise values of flux function at the solution points, which are computed directly from the dependent variables, as well as the numerical fluxes at the boundaries of the computational element, which are obtained as Riemann solutions between the adjacent elements. Given the reconstructed flux function, the time tendencies of the unknowns can be obtained directly from the governing equations of differential form. The resulting schemes have super convergence and rigorous numerical conservativeness. A three-point scheme of fifth-order accuracy is presented and analyzed in this paper. The proposed scheme is adopted to develop the global shallow-water model on the cubed-sphere grid, where the local high-order reconstruction is very beneficial for the data communications between adjacent patches. We have used the standard benchmark tests to verify the numerical model, which reveals its great potential as a candidate formulation for developing high-performance general circulation models.

Screening methodologies for the development of spray-dried amorphous solid dispersions.

To present a new screening methodology intended to be used in the early development of spray-dried amorphous solid dispersions. A model that combines thermodynamic, kinetic and manufacturing considerations was implemented to obtain estimates of the miscibility and phase behavior of different itraconazole-based solid dispersions. Additionally, a small-scale solvent casting protocol was developed to enable a fast assessment on the amorphous stability of the different drug-polymer systems. Then, solid dispersions at predefined drug loads were produced in a lab-scale spray dryer for powder characterization and comparison of the results generated by the model and solvent cast samples. The results obtained with the model enabled the ranking of the polymers from a miscibility standpoint. Such ranking was consistent with the experimental data obtained by solvent casting and spray drying. Moreover, the range of optimal drug load determined by the model was as well consistent with the experimental results. The screening methodology presented in this work showed that a set of amorphous formulation candidates can be assessed in a computer model, enabling not only the determination of the most suitable polymers, but also of the optimal drug load range to be tested in laboratory experiments. The set of formulation candidates can then be further fine-tuned with solvent casting experiments using a small amount of API, which will then provide the decision for the final candidate formulations to be assessed in spray drying experiments.

Synthesis of a semi-interpenetrating polymer network as a bioactive curcumin film.

This study focused on the synthesis and characterization of a natural polymeric system employing the interpenetrating polymer network (IPN) comprising curcumin as a bioactive. Biopolymers and actives such as chitosan, hypromellose, citric acid, genipin, and curcumin were used to develop an effective, biodegradable, and biocompatible film employed therapeutically as a wound healing platform. The semi-IPN films were investigated for their physicochemical, physicomechanical, and biological properties by quantification by FTIR, DSC, and Young's modulus. Following characterization, an optimum candidate formulation was produced whereby further in vitro and ex vivo studies were performed. Results revealed a burst release occurring at the first hour with 1.1 mg bioactive released when in contact with the dissolution medium and 2.23 mg due to bioactive permeation through the skin, thus suggesting that the lipophilic nature of skin greatly impacted the bioactive release rate. Furthermore, chemical and mechanical characterization and tensile strength analysis revealed that the degree of crosslinking and concentration of polymeric material used significantly influenced the properties of the film.

In Situ-Formed Microparticles of PLGA from O/W Emulsions Stabilized with PVA: Encapsulation and Controlled Release of Progesterone

In situ-formed microspheres are an alternative to expensive and complex manufactured preformed systems for the controlled release of drugs. The aim of this study was to evaluate the potential of stable O/W emulsions to entrap progesterone after in vitro precipitation of poly(d,l-lactide-co-glycolide) (PLGA) microparticles. This was achieved by a solvent selection based on their miscibility and capability to solubilize the drug and PLGA. Stability assays, size distribution studies, and progesterone encapsulation efficiency evaluation were carried out for the candidate formulations. After selection of the most suitable formulations, in vitro-controlled release test of progesterone were done. Results demonstrate that emulsions based on triacetin and polyvinyl alcohol (PVA) aqueous solutions were useful solvent systems to obtain microspheres capable to deliver the hormone in a controlled release manner. In addition, for the first time, for these authors, PVA was successfully implemented into a continuous phase to increase the stability of in situ-formed O/W formulations.

Testing a new formulation for Peste des Petits Ruminants vaccine in Ethiopia

In this paper extended tests on a new candidate formulation for Peste des Petits Ruminants (PPR) vaccine carried out at National Veterinary Institute (NVI) in Ethiopia are presented. This work was performed in the frame of the VACNADA project from GALVmed which aimed at procuring vaccines against neglected veterinary diseases to African vaccine producing laboratories, in particular PPR.After the eradication of Rinderpest, Peste des Petits Ruminants became the next veterinary disease on target for elimination, requiring an effective and thermostable vaccine. In this work a Tris/Trehalose formulation was evaluated in thermal stability studies in comparison to the current used formulation of the live attenuated PPR vaccine, the Weybridge medium. The extended results presented herein show an increased thermal stability of the vaccine, especially at 37 and 45°C, as expected from previously published results (Silva A.C. et al., 2011). Furthermore, during the course of this project, the NVI teams have clearly demonstrated ability to produce higher quality PPR vaccines after a successful transfer of the technology. These results should significantly enhance the utility of the vaccine in the eradication of PPR.

Investigation of in situ gelling alginate formulations as a sustained release vehicle for co-precipitates of dextromethrophan and Eudragit S 100

Alginate vehicles are capable of forming a gel matrix in situ when they come into contact with gastric medium in the presence of calcium ions. However, the gel structure is pH dependent and can break after gastric emptying, leading to dose dumping. The aim of this work was to develop modified in situ gelling alginate formulations capable of sustaining dextromethorphan release throughout the gastrointestinal tract. Alginate solution (2 %, m/m) was used as a vehicle for the tested formulations. Solid matrix of the drug and Eudragit S 100 was prepared by dissolving the drug and polymer in acetone. The organic solvent was then evaporated and the deposited solid matrix was micronized, sieved and dispersed in alginate solution to obtain candidate formulations. The release behavior of dextromethorphan was monitored and evaluated in a medium simulating the gastric and intestinal pH. Drug-polymer compatibility and possible solid-state interactions suggested physical interaction through hydrogen bonding between the drug and the polymer. A significant decrease in the rate and extent of dextromethorphan release was observed with increasing Eudragit S 100 concentration in the prepared particles. Most formulations showed sustained release profiles similar to that of a commercial sustained-release liquid based on ion exchange resin. The release pattern indicated strict control of drug release both under gastric and intestinal conditions, suggesting the potential advantage of using a solid dispersion of drug-Eudragit S 100 to overcome the problem of dose dumping after the rupture of the pH dependent alginate gels.

Where are you? Location talk in mobile phone conversations

Conversational studies have shown that location cannot be considered as an external framework that shapes interaction; rather it is to be analyzed as a resource and an achievement in interaction (Schegloff, 1972). Building on a corpus of 93 recorded mobile phone conversations from the United States and Denmark, this article adds to current interaction research by investigating how location is produced, understood and socially accomplished via mobile phones. More specifically, we investigate how location talk operates in the opening sequences of the call. We find that location is an opening-relevant topic: speakers introduce it as the reason for the call and topicalize it following initial engagement. When referring to location, speakers predominately use two variations: inquiries (where are you), and reports of their whereabouts (I just got home). Further, speakers formulate their locations in two ways: location specific (I’m sitting on a train) or status of transit (we are on our way). In addition to open format where-are-you elicitations, location talk can take the form of a candidate (are you at Union street); candidate formulations show how speakers orient to the collaborative work of meeting up with one another and display knowledge about each other’s activities. Finally, we treat the case of reciprocal location inquiries and reports, where both caller and callee state their whereabouts, showing how location talk is sequence organized.

MedinGel™: a controlled-release platform for intraarticular delivery of osteoarthritis drugs

Purpose: Current osteoarthritis treatments have clear delivery limitations and are principally designed to treat symptoms. Drawbacks include inefficient penetration of drugs into the joint space, systemic side effects and short duration of action. Drugs administered for systemic release have poor synovial penetration that is required to provide relief from OA-related pain and inflammation. High plasma concentrations of many NSAID compounds lead to severe side effects such as stomach pain and ulcers. And in the case of orally administered celecoxib, warnings of increased risk for heart attack and stroke have been issued. MedinCell will present our company's experience in designing polymer-based delivery technology to circumvent these problems with the goal of improving osteoarthritis treatments. We will discuss the use of our MedinGel™ platform for multi-month local delivery of small molecules and biologics to help control pain, reduce inflammation and promote cartilage repair. Without controlled release capability, drugs injected directly into the joint spaces are often cleared within hours. Yet daily intraarticular injections are untenable, as they would have to be administered by trained clinicians and would severely impact the patients’ quality of life. Additionally, a high frequency of injections into the joint could have increased risk of bacterial infection. By tailoring formulations to specific drugs for a range of delivery durations, MedinCell is confident that intraarticular formulations can deliver a sustained therapeutic drug concentration over multiple months to obviate current concerns and improve both treatment efficacy and patient compliance. Methods: After evaluation of drug solubility and set up of in vitro-release assays, a series of sets of formulations evaluating combinations of polymers at different concentrations were prepared. The MedinGel matrix is composed of mixtures of drug molecules with solubilized, bioresorbable polymers. Within minutes after injection through a fine needle, the aqueous environment of the joint leads to a phase-separation of the formulated polymers and formation of a three-dimensional matrix. This resulting semi-solid hydrogel depot entraps and protects drug molecules within the joint space, and minimizes clearance to the plasma. Results: Candidate formulations that provided a range of drug release rates in vivo were evaluated. The best candidates were then tested by intraarticular injection. MedinCell has designed intraarticular formulations of OA drug therapies that maintained therapeutic synovial concentrations for a 3-month duration in animals. Conclusions: The MedinGel platform enables control over the initial drug burst characteristics, allowing the remainder of the drug to be released over a predetermined duration via polymer hydrolysis and drug diffusion until the depot is completely resorbed. No covalent modification of the active substance is required, which can simplify regulatory and development pathways. We will present data showing differential compartmentalization of drug between joint and plasma when comparing normal injection to MedinGel delivery. Additionally, MedinCell expects that this technology will provide effective delivery of disease-modifying caspase inhibitors and proteins (such as BMP7) for trauma-induced arthritis.

Screening paediatric rectal forms of azithromycin as an alternative to oral or injectable treatment.

The aim of this study was to identify a candidate formulation for further development of a home or near-home administrable paediatric rectal form of a broad-spectrum antibiotic - specially intended for (emergency) use in tropical rural settings, in particular for children who cannot take medications orally and far from health facilities where injectable treatments can be given. Azithromycin, a broad-spectrum macrolide used orally or intravenously for the treatment of respiratory tract, skin and soft tissue infections, was selected because of its pharmacokinetic and therapeutic properties. Azithromycin in vitro solubility and stability in physiologically relevant conditions were studied. Various pharmaceutical forms, i.e. rectal suspension, two different rectal gels, polyethylene glycol (PEG) suppository and hard gelatin capsule (HGC) were assessed for in vitro dissolution and in vivo bioavailability in the rabbit. Azithromycin PEG suppository appears to be a promising candidate.

Dissolution Testing of Acetaminophen Suspension Using Dialysis Adapter in Flow-Through Apparatus: A Technical Note

Dissolution testing is an important tool during drug development, characterization, and quality control of both immediate- and controlled-release formulations. It has been used for evaluating candidate formulations and for understanding possible risks related to specific gastrointestinal factors, potential for dose dumping, food effects on bioavailability, and interaction with excipients (1,2). Recently, dissolution testing has been increasingly used to test dosage forms such as suspensions, soft gelatin capsules, creams and transdermal systems. To test these special dosage forms, special accessories are sometimes required. SOTAX Inc. recently introduced a dialysis adapter for release testing of solution and semisolid formulations. This device, as shown in Fig. 1, facilitates the use of dialysis tubing to sequester a sample in the center of the USP 4 standard 22.6 mm flow cell. The applications with this dialysis adapter are mainly for in vitro release testing of dispersed dosage forms. One publication by Burgess’ group using this method compared dexamethasone release from extruded and non-extruded liposomes (3). Results showed that the USP apparatus 4 method with this dialysis adapter could discriminate between solution, suspension, and liposome formulations of dexamethasone. Fig. 1 Dialysis adapter from Sotax Inc The objective of this study was to evaluate this new dialysis adapter. An acetaminophen suspension drug product and various concentration acetaminophen solution samples were used to compare the flow-through method with and without the dialysis adapter, as well as to compare two different sizes of dialysis membranes. Other parameters such as flow rate, dissolution media, and medium ionic strengths were also studied.

A New In-Situ Gel Formulation of Itraconazole for Vaginal Administration

In this paper, mucoadhesive in-situ gel with poloxamer and hydroxypropylmethylcellulose formulations of itraconazole were prepared for vaginal application. In addition, rheological, mechanical and mucoadhesive properties and syringeability of the formulations were characterized. The mixtures of Poloxamer 407 and 188 with two different types of hydroxypropylmethylcellulose were used as polymers for gel formulations. Flow rheometry studies and oscillatory analysis of each formulation were performed at 20℃ ± 0.1℃ and 37℃ ± 0.1℃. All formulations exhibited pseudo-plastic flow and typical gel-type mechanical spectra (G′ > G″) after the determined frequency value at 37℃. Texture profile analysis presented that F3 formulation containing 20% poloxamer 407, 10% poloxamer 188 and 0.5% hydroxypropylmethylcellulose appeared to offer more suitable mechanical and mucoadhesive performance. Using different hydroxypropylmethylcellulose type in formulations didn’t significantly change syringeability values. The evaluation of the entire candidate formulations indicated that vaginal formulation of itraconazole will be an alternative for the treatment of vaginal candidiasis with suitable textural and rheological properties. Our results showed that the developed formulations were found worthy of further studies.

Physical characterisation and component release of poly(vinyl alcohol)–tetrahydroxyborate hydrogels and their applicability as potential topical drug delivery systems

Poly(vinyl alcohol)–tetrahydroxyborate (PVA–THB) hydrogels are dilatant formulations with potential for topical wound management. To support this contention, the physical properties, rheological behaviour and component release of candidate formulations were investigated. Oscillatory rheometry and texture profile analysis were used at room temperature and 37°C. Results showed that it was possible to control the rheological and textural properties by altering component concentration and modifying the type of PVA polymer used. Hydrogels made using PVA grades with higher degrees of hydrolysis displayed favourable characteristics from a wound healing perspective. In vitro release of borate and PVA were assessed in order to evaluate potential clinical dosing of free species originating from the hydrogel structure. Component diffusion was influenced by both concentration and molecular weight, where relevant, with up to 5% free PVA cumulative release observed after 30min. The results of this study demonstrated the importance of poly(vinyl alcohol) selection for ensuring appropriate gel formation in PVA–THB hydrogels. The benefits of higher degrees of hydrolysis, in particular, included lower excipient release and reduced bioadhesion. The unique physical characteristics of these hydrogels make them an appealing delivery vehicle for chronic and acute wound management purposes.

OTO-104

To investigate whether OTO-104, a poloxamer-based hydrogel containing micronized dexamethasone for intratympanic delivery, can provide long-lasting inner ear exposure and be well tolerated. OTO-104 was administered intratympanically to guinea pigs and sheep, and its pharmacokinetic and toxicity profiles were examined. After a single intratympanic injection of OTO-104 (from 0.6% to 20%, w/w), significant and prolonged exposure to dexamethasone in the inner ear was observed. Increasing the concentration of OTO-104 resulted in higher perilymph drug levels as well as a more prolonged duration of exposure. At the highest dose, therapeutic perilymph levels of dexamethasone could be sustained over 3 months in guinea pigs and more than 1 month in sheep. A toxicologic evaluation was conducted, including assessments of middle and inner ear function and physiology, as well as appraisal of local and systemic toxicity. A small and transient shift in hearing threshold was observed, most probably conductive in nature. No significant histologic changes in middle or inner ear tissues were noted. Although macroscopically mild erythema/inflammation was documented in a subset of guinea pigs treated with 20% OTO-104, the nature and the severity of these changes were not different between the poloxamer vehicle, saline, and 20% OTO-104 groups. No evidence of acute dermal toxicity, delayed hypersensitivity, or systemic adverse effects was found. OTO-104 is a novel proprietary therapeutic delivery system that can achieve prolonged, sustained release of dexamethasone within the inner ear fluids. The administration of this clinical candidate formulation via intratympanic injection is expected to be well tolerated both locally and systemically.

Tablet Tensile Strength: An Adhesion Science Perspective

Tablets are the most common dosage form employed by the pharmaceutical industry. They are both inexpensive to produce and convenient to patients. Active pharmaceutical ingredients, particularly those incorporated into innovator company products, are new chemical substances whose chemical and physical properties are incompletely known and are sometimes present in large amounts in the manufactured products. Excipients present in the formulation can, at least partially, offset undesirable properties of active ingredient. Successful tablet formulations must, in addition to having desirable medicinal properties, must be manufacturable. In order to be manufacturable tablets must have sufficient tensile strength to survive handling, processing and packaging. In this paper the tensile strength of common pharmaceutical excipients mixed with sodium dodecyl sulfate is investigated. Sodium dodecyl sulfate, if incorporated into formulations, usually has an undesirable effect on tensile strength. A model, based on adhesion science principles is proposed that allows the tensile strength of candidate formulations to be calculated from the Ryshkewitch–Duckworth parameters of the component materials. Both the model and the Ryshkewitch–Duckworth equation suggest that tablet porosity is the principal measure of the outcome of the tableting process.

Oral self-emulsifying drug delivery systems, from biopharmaceutical to technical formulation aspects

Self-emulsifying drug delivery systems can include a broad range of oils, surfactants and co-solvents. A spontaneous fine emulsion or micro-emulsion is formed in contact with water or gastro-intestinal fluids. There is a growing interest in this pertinent drug delivery approach and a key rationale is to formulate biopharmaceutically challenging drugs. In this review, a structured method is presented for how oral self-emulsifying formulations can be developed. The screening of drug solubility in excipients and the study of phase behavior are discussed in the first step. This initial development phase should also consider the known biological effects of selected excipients. Following the identification of candidate formulations, different in vitro tests are performed to mimic the fate of the formulation in vivo. The early dilution and dispersion tests can run in parallel on a small scale to primarily characterize the systems and to screen for unfavorable phase separation or precipitation of the drug. At a later stage, compendial equipment is used and dynamic lipolysis testing can provide valuable information about the digestion of the formulation. The next step is the performance evaluation of selected formulations in animals. Finally, technical aspects of different capsule and filling technologies are addressed in order to connect the early biopharmaceutical considerations with aspects of the dosage form manufacture.