Convolution- and Deconvolution-Based Approaches for Prediction of Pharmacokinetic Parameters of Diltiazem Extended-Release Products in Flow-Through Cell Dissolution Tester.

The present study evaluated the effect of different configuration setups of the Flow-Through Cell (USP IV) dissolution tester in developing in vitro-in vivo correlation (IVIVC). A Biopharmaceutics Classification System (BCS) Class I Diltiazem (DTZ), formulated in extended-release (ER) gel-matrix system, was employed for this purpose. The study also assessed the validity and predictability of IVIVC employing both deconvolution- and convolution-based approaches. In vitro release was conducted in USP IV as open- or closed-loop setups, while the pharmacokinetic (PK) data were obtained from a previous fasted-state cross-over study conducted on 8 healthy male volunteers, after oral administration of ER matrix tablets against market product (Tildiem Retard® 90 mg). PK parameters (Cmax, AUC0-t and AUC0-∞) were predicted, and compared with actual data to establish the strength of correlation models. Results showed that DTZ release from ER products was influenced by operating the FTC in different configuration-setups, where ≥ 75% of labeled DTZ was released after 6 h and 12 h using the open- and closed-loop settings, respectively. Correlation between fraction-dissolved versus fraction-absorbed for both ER products displayed linear relation upon employing FTC open-loop setup. Convolution-based approach was more discriminative in predicting DTZ in vivo PK parameters with a minimal prediction error, compared to deconvolution-based approach. A successful trial to predict DTZ PKs from individual in vitro data performed in USP IV dissolution model was established, employing convolution technique. Basic principle of the convolution approach provides a simple and practical method for developing IVIVC, hence could be utilized for other BCS Class I extended-release drug products.

Probing in Vitro Release Kinetics of Long-Acting Injectable Nanosuspensions via Flow-NMR Spectroscopy.

Novel treatment routes are emerging for an array of diseases and afflictions. Complex dosage forms, based on active pharmaceutical ingredients (APIs) with previously undesirable physicochemical characteristics, are becoming mainstream and actively pursued in various pipeline initiatives. To fundamentally understand how constituents in these dosage forms interact on a molecular level, analytical methods need to be developed that encompass selectivity and sensitivity requirements previously reserved for a myriad of in vitro techniques. The knowledge of precise chemical interactions between drugs and excipients in a dosage form can streamline formulation development and process screening capabilities through the identification of properties that influence rates and mechanisms of drug release in a cost-effective manner, relative to long-term in vivo studies. Through this work, a noncompendial in vitro release (IVR) method was developed that distinguished the presence of individual components in a complex crystalline nanosuspension environment. Doravirine was formulated as a series of long-acting injectable nanosuspensions with assorted excipients, using low- and high-energy wet media milling methods. IVR behavior of all formulation components were monitored using a robust continuous flow-through (CFT) dissolution setup (USP-4 apparatus) with on-line 1H NMR end-analysis (flow-NMR). Results from this investigation led to a better understanding of formulation parameter influences on nanosuspension stability, surface chemistry, and dissolution behavior. Flow-NMR can be applied to a broad range of dosage forms in which specific molecular interactions from the solution microenvironment require further insight to enhance product development capabilities.

Filling of lactose-based formulations in a tamping-pin capsule filler.

We studied three lactose-based formulations in terms of bulk powder properties and capsule-filling behavior in a tamping-pin capsule filling system, to which several mechanical adaptions were made for process optimization in light of future continuous production. The model formulations were thoroughly characterized and filled into size 1 capsules according a well-defined design of experiments (DoE). Overall, the three entirely different formulations were successfully filled within the selected design space. The fill weight and fill weight variability can be adjusted by fine-tuning the process settings, like the pin immersion depth and the maximum compaction pressure (pneumatic or spring-controlled), and by using the appropriate powder bed height and mechanical adaptions. This study demonstrated that selection of process parameters and mechanical adaptions could enhance the filling performance, especially in continuous production, since they reduce the powder volume in the process. Moreover, we showed that a tamping-pin system is capable of successfully filling a broad range of powders with various material characteristics and can potentially be used in a continuous production mode.

Microwave Assisted Reactions of Azaheterocycles Formedicinal Chemistry Applications.

Microwave (MW) assisted reactions have became a powerful tool in azaheterocycles chemistry during the last decades. Five and six membered ring azaheterocycles are privileged scaffolds in modern medicinal chemistry possessing a large variety of biological activity. This review is focused on the recent relevant advances in the MW assisted reactions applied to azaheterocyclic derivatives and their medicinal chemistry applications from the last five years. The review is divided according to the main series of azaheterocycles, more precisely 5- and 6-membered ring azaheterocycles (with one, two, and more heteroatoms) and their fused analogues. In each case, the reaction pathways, the advantages of using MW, and considerations concerning biological activity of the obtained products were briefly presented.

Flow Chemistry in Contemporary Chemical Sciences: A Real Variety of Its Applications.

Flow chemistry is an area of contemporary chemistry exploiting the hydrodynamic conditions of flowing liquids to provide particular environments for chemical reactions. These particular conditions of enhanced and strictly regulated transport of reagents, improved interface contacts, intensification of heat transfer, and safe operation with hazardous chemicals can be utilized in chemical synthesis, both for mechanization and automation of analytical procedures, and for the investigation of the kinetics of ultrafast reactions. Such methods are developed for more than half a century. In the field of chemical synthesis, they are used mostly in pharmaceutical chemistry for efficient syntheses of small amounts of active substances. In analytical chemistry, flow measuring systems are designed for environmental applications and industrial monitoring, as well as medical and pharmaceutical analysis, providing essential enhancement of the yield of analyses and precision of analytical determinations. The main concept of this review is to show the overlapping of development trends in the design of instrumentation and various ways of the utilization of specificity of chemical operations under flow conditions, especially for synthetic and analytical purposes, with a simultaneous presentation of the still rather limited correspondence between these two main areas of flow chemistry.

Translational formulation of nanoparticle therapeutics from laboratory discovery to clinical scale.

BACKGROUND: "Nanomedicine" is the application of purposely designed nano-scale materials for improved therapeutic and diagnostic outcomes, which cannot be otherwise achieved using conventional delivery approaches. While "translation" in drug development commonly encompasses the steps from discovery to human clinical trials, a different set of translational steps is required in nanomedicine. Although significant development effort has been focused on nanomedicine, the translation from laboratory formulations up to large scale production has been one of the major challenges to the success of such nano-therapeutics. In particular, scale-up significantly alters momentum and mass transfer rates, which leads to different regimes for the formation of nanomedicines. Therefore, unlike the conventional definition of translational medicine, a key component of "bench-to-bedside" translational research in nanomedicine is the scale-up of the synthesis and processing of the nano-formulation to achieve precise control of the nanoscale properties. This consistency requires reproducibility of size, polydispersity and drug efficacy. METHODS: Here we demonstrate that Flash NanoPrecipitation (FNP) offers a scalable and continuous technique to scale up the production rate of nanoparticles from a laboratory scale to a pilot scale. FNP is a continuous, stabilizer-directed rapid precipitation process. Lumefantrine, an anti-malaria drug, was chosen as a representative drug that was processed into 200 nm nanoparticles with enhanced bioavailability and dissolution kinetics. Three scales of mixers, including a small-scale confined impinging jet mixer, a mid-scale multi-inlet vortex mixer (MIVM) and a large-scale multi-inlet vortex mixer, were utilized in the formulation. The production rate of nanoparticles was varied from a few milligrams in a laboratory batch mode to around 1 kg/day in a continuous large-scale mode, with the size and polydispersity similar at all scales. RESULTS: Nanoparticles of 200 nm were made at all three scales of mixers by operating at equivalent Reynolds numbers (dynamic similarity) in each mixer. Powder X-ray diffraction and differential scanning calorimetry demonstrated that the drugs were encapsulated in an amorphous form across all production rates. Next, scalable and continuous spray drying was applied to obtain dried powders for long-term storage stability. For dissolution kinetics, spray dried samples produced by the large-scale MIVM showed 100% release in less than 2 h in both fasted and fed state intestinal fluids, similar to small-batch low-temperature lyophilization. CONCLUSIONS: These results validate the successful translation of a nanoparticle formulation from the discovery scale to the clinical scale. Coupling nanoparticle production using FNP processing with spray drying offers a continuous nanofabrication platform to scale up nanoparticle synthesis and processing into solid dosage forms.

Probing Thermal Stability of Proteins with Temperature Scanning Viscometer.

Thermal stability is essential for the understanding of protein stability and is a critical quality attribute of therapeutic biologics, including enzymes, fusion proteins, monoclonal antibodies, etc. The commonly used analytical methods, such as differential scanning calorimetry (DSC), differential scanning fluorimetry (DSF), and circular dichroism (CD), have their limitations in measuring protein thermal stability. Through this work, we described a novel method to probe the thermal stability of proteins in various formulations using a temperature scanning viscometer. The viscosity of the material was plotted against the temperature, and the peak in the first derivative of the viscosity versus temperature was shown to be related to the protein melting temperature. The measured melting temperature of bovine serum albumin (BSA) at a concentration of 1 mg/mL in phosphate buffer was 63 °C, which was close to the value of 64 °C obtained by DSC. The unfolding of BSA was confirmed using orthogonal techniques of second derivative ultraviolet-visible (UV-vis) spectroscopy and dynamic light scattering (DLS). This method was also able to reveal the microenvironment changes of proteins, including formulation effects. Other multiple domains proteins including lysozyme and IgG were also tested using this method and showed comparable melting temperatures with DSC. This work showed the feasibility of using a temperature scanning viscometer to measure the thermal stability of proteins in diverse formulation matrices with wider protein concentration ranges.

Polymeric Reactor for the Synthesis of Superparamagnetic-Thermal Treatment of Breast Cancer.

Engineered superparamagnetic iron oxide nanoparticles (SPIONs) have been studied extensively for their localized homogeneous heat generation in breast cancer therapy. However, challenges such as aggregation and inability to produce sub-10 nm SPIONs limit their potential in magnetothermal ablation. We report a facile, efficient, and robust in situ method for the synthesis of SPIONs within a poly(ethylene glycol) (PEG) reactor adsorbed onto reduced graphene oxide nanosheets (rGO) via the microwave hydrothermal route. This promising modality yields crystalline, stable, biocompatible, and superparamagnetic PEGylated SPION-rGO nanocomposites (NCs) with uniform dispersibility. Our findings show that rGO acts as a breeding ground for the spatially distributed nanosites around which the ferrihydrite seeds accumulate to ultimately transform into immobilized SPIONs. PEG, in parallel, acts as a critical confining agent physically trapping the accumulated seeds to prevent their aggregation and create multiple domains on rGO for the synthesis of quantum-sized SPIONs (9 ± 1 nm in diameter). This dual functionality (rGO and PEG) exhibits a pronounced effect on reducing both the aggregation and the sizes of fabricated SPIONs as confirmed by the scanning transmission electron microscopy images, dynamic light scattering analyses, and the specific absorption rates (SARs). Reduced aggregation lowered the toxicity of NCs, where PEGylated SPION-rGO NCs are more biocompatible than PEGylated SPIONs, showing no significant induction of cell apoptosis, mitochondrial membrane injury, or oxidative stress. Significantly less lactate dehydrogenase release and hence less necrosis are observed after 48 h exposure to high doses of PEGylated SPION-rGO NCs compared with PEGylated SPIONs. NCs induce local heat generation with a SAR value of 1760 ± 97 W/g, reaching up to 43 ± 0.3 °C and causing significant MCF-7 breast tumor cell ablation of about 78 ± 10% upon applying an external magnetic field. Collectively, rGO and PEG functionalities have a synergistic effect on improving the synthesis, stability, biocompatibility, and magnetothermal properties of SPIONs.

Novel Dissolution Approach for Tacrolimus-Loaded Microspheres Using a Dialysis Membrane for in Vitro-in Vivo Correlation.

The aim of this study was to establish a novel approach to in vitro dissolution evaluation using a combination of the paddle method and a dialysis membrane, both to predict the overall in vivo performance of tacrolimus microspheres and also to identify a suitable dissolution test method to describe the in vivo initial burst phenomenon. This new dissolution method for evaluating the release of tacrolimus from microspheres consisted of rotating a customized paddle inside a dialysis membrane using a conventional paddle apparatus. Findings were compared with a method in which the paddle was rotated outside the dialysis membrane, the conventional paddle method, and the flow-through cell method. We concluded that the paddle method with a dialysis membrane and internal agitation, which was designed to mimic in vivo conditions, predicted the overall pharmacokinetic (PK) profile of tacrolimus microspheres whereas the conventional paddle method described the initial burst. These findings suggest that it may not be possible to predict both the PK profile and initial burst using a single analysis method. We therefore recommend that evaluation of the initial burst be performed separately. In conclusion, we propose that combination of the paddle method with a dialysis membrane and internal agitation to evaluate the overall PK profile, together with the paddle method to describe the in vivo initial burst, represents a novel approach to in vitro dissolution evaluation for microsphere formulations.

Elucidating spray-dried dispersion dissolution mechanisms with focused beam reflectance measurement: contribution of polymer chemistry and particle properties to performance.

Amorphous spray-dried dispersions (SDDs) are a key enabling technology for oral solid dosage formulations, used to improve dissolution behaviour and clinical exposure of poorly soluble active pharmaceutical ingredients (APIs). Appropriate assessment of amorphous dissolution mechanisms is an ongoing challenge. Here we outline the novel application using focused beam reflectance measurement (FBRM) to analyse particle populations orthogonal to USP 2 dissolution. The relative impact of polymer substitution and particle attributes on 25% BMS-708163/HPMC-AS SDD dissolution was assessed. Dissolution mechanisms for SDDs were categorized into erosion versus disintegration. Beyond an initial mixing period, FBRM particle counts diminish slowly and particles are detectable until the point where API dissolution is complete. There is correlation between FBRM particle count decay rate, representing loss of SDD particles in the dissolution media, and UV dissolution rate, measuring dissolved API. For the SDD formulation examined, the degree of succinoyl substitution for HPMC-AS, SDD particle size and surface area all had an impact on dissolution. These data indicate the SDD displayed an erosion mechanism and that FBRM is capturing a rate-limiting step. From this screening tool, the mechanistic understanding and measured impact of polymer chemistry and particle properties can inform a risk-assessment and control strategy for this compound.

An Investigation of Magnesium Stearate Mixing Performance in a V-Blender Through Passive Vibration Measurements.

Prior to compression in tablet manufacturing, a lubricant is added and mixed in a V-blender to ensure the mixture is ejected from the tablet die smoothly. Mixing is conducted batch-wise and must be analyzed offline afterwards to ensure the mixture is uniform and will produce desired tablet properties, thereby a costly and time-consuming step within the manufacturing process. To improve process efficiency, inline monitoring methods using passive acoustic emissions or vibration measurements could be implemented. Methods are non-destructive, non-invasive, and have a reduced capital cost compared to traditional methods. Using an accelerometer affixed to the lid of the V-shell, magnesium stearate was added to glass beads and monitored to determine the effect of loading configuration and fill level on mixing performance and measured vibrations. Axial loading configurations performed better than radial configurations due to the limited axial dispersion from the geometry of the V-shell. Mixing was hindered at an increased fill level due to convective and axial dispersion. The optimal fill level of a V-blender was found to be 21-23% by volume. Monitoring magnesium stearate mixing using passive vibration measurements is a non-intrusive and potentially inline method that could significantly improve pharmaceutical process efficiency.

Small-Scale Tools to Assess the Impact of Interfacial and Shear Stress on Biologic Drug Products.

Proper risk analysis needs to be in place to understand the susceptibility of protein to unfold and aggregate in the presence of interfacial and/or shear stress. Certain techniques, such as agitation/shaking studies, have been traditionally used to understand the impact of these stresses on the protein physical stability. However, the stresses applied in these systems are convoluted, making it difficult to define the control strategy (i.e., adjustment in process parameters to reduce foaming/bubble formation, change pump type). We have developed two small-scale tools that allow for the isolation of interfacial and shear stress, respectively. These systems, in combination with computational fluid dynamics and numerical approximations, help simulate the normal operating ranges as well as the proven acceptable ranges for different unit operations such as tangential flow filtration (TFF), mixing, and filling.

Ranking in Vitro Dissolution of Inhaled Micronized Drug Powders including a Candidate Drug with Two Different Particle Sizes.

Pulmonary dissolution of poorly soluble drug substances (DSs) may limit the drug absorption rate and consequently influence clinical performance. Dissolution rate is thus an important quality attribute, and its influence on in vivo drug release must be characterized, understood, and controlled early in the development process. The aim of this study is to establish an in vitro dissolution method with the capability to capture therapeutically relevant differences in the dissolution rate between drug batches and drug compounds. A method was developed by which a biorelevant aerosol fraction was captured on a filter using a sedimentation technique in a modified Andersen cascade impactor to avoid particle agglomeration. Subsequently, the filters were transferred to a commercial Transwell system where dissolution in 3 mL of phosphate buffer at pH 6.8 with 0.5% sodium dodecyl sulfate (SDS) occurred at sink conditions. Dissolved DS was quantified over time using UPLC-UV. Dissolution data was obtained on a series of micronized and aerosolized lipophilic DSs, budesonide, fluticasone furoate (FF), fluticasone propionate (FP), and AZD5423. The latter is a lipophilic AstraZeneca development compound available in two different mass median diameters (MMD), 1.3 (AZD54231.3) and 3.1 µm (AZD54233.1). Dissolution data were evaluated using a Weibull fit and expressed as t63, the time to dissolution of 63% of the initial dose. The following rank-order of t63 was obtained (mean t63 and MMD in brackets), budesonide (10 min, 2.1 µm) = AZD54231.3 (10 min, 1.3 µm) < AZD54233.1 (19 min, 3.1 µm) < FP (38 min, 2.4 µm) < FF (63 min, 2.5 µm). The method could differentiate between different drug compounds with different solubility but similar particle size distribution, as well as between the same drug compound with different particle size distributions. Furthermore, a relation between the in vitro dissolution rate ( t63) and mean pulmonary absorption time in man (literature data) was observed, indicating clinical relevance. It is thus concluded, that the method may be useful for the characterization and ranking of DSs and drug products in early development, as well as being a potential tool for the control of dissolution as a potential quality attribute.

Microarray Plate Method for Estimation of Precipitation Kinetics of Celecoxib under Biorelevant Conditions and Precipitate Characterization.

Study methodologies of supersaturated state are fast developing as pharmaceutical industry is adopting supersaturating drug delivery systems (SDDS) to overcome the solubility issue of drugs. The "parachute" of sobriquet "spring-and-parachute", which indicates delayed or slowed intraluminal precipitation of drug from SDDS, is of immense importance to formulation scientists since optimal attainment of "parachute" governs the success of SDDS in stabilizing supersaturated state that ensues in enhancement of bioavailability. The studies carried out so far for precipitation assessments have ignored the stochastic nature of nucleation and lack absolute mathematical approach. In the current study, the supersaturated state has been studied in a quantitative manner through microarray plate method with application of the classical nucleation theory (CNT) equation for determination of precipitation kinetics. This microarray plate method is an attempt to pursue the principle of miniaturization in supersaturation assays and involves comprehensive measurements that allows for accounting of the stochastic nature of nucleation. Overcoming the drawbacks of reproducibility and greater material requirement of existing methods, this study aims to quantify the rate of in vivo precipitation through understanding of precipitation profile of model drug, celecoxib, in biorelevant media. Quantification of nucleation rates was made through CNT using tailored criteria and visually represented through temporal precipitation distribution (TPD) plots. Supersaturation stability was also compared through metastable zone width (MSZW). Optical microscopy helped in visualizing the dynamics of precipitation, while solid state characterization assisted in understanding the nature of obtained precipitates. This study identified the short-lived supersaturation of celecoxib and its tendency to precipitate under fasted conditions, which can be correlated with in vivo behavior for formulation design.

Establishment and Validation of Competitive Counterflow as a Method To Detect Substrates of the Organic Anion Transporting Polypeptide 2B1.

The organic anion transporting polypeptide (OATP) 2B1 is ubiquitously expressed and known to facilitate cellular entry. It is widely accepted that transport proteins play a pivotal role in pharmacokinetics. Consequently, testing for interaction with drug transporters became an important part in the assessment of new molecular entities in order to predict and prevent drug-drug interactions. Recently, competitive counterflow (CCF), an indirect method allowing the identification of substrates, was successfully applied to the organic cation transporter 2. It was the aim of this study to test whether CCF can be used to identify substrates of OATP2B1. A protocol for CCF experiments using estrone 3-sulfate (E1S) as the driven compound in expression-verified MDCKII-OATP2B1 cells was established. The protocol was tested using a substance library, which was prior screened for inhibition of OATP2B1-mediated transport accounting for both E1S-binding sites. In CCF experiments, all previously reported OATP2B1 substrates significantly reduced the amount of E1S in equilibrium, classifying them as substrates. In addition, we identified and verified novel substrates of OATP2B1, namely, astemizole and domperidone. Results of the CCF were complemented with cytotoxicity assays or cell-based reporter gene assays to validate the finding of etoposide and teniposide or hyperforin being substrates of OATP2B1, respectively. Our study indicates that the method of CCF can be used to identify substrates of OATP2B1, irrespective, whether interacting with binding site A or A and B, but is limited by solubility issues or the amount of transporter that is expressed in the used cellular system.

Measuring The Bipolar Charge Distributions of Fine Particle Aerosol Clouds of Commercial PMDI Suspensions Using a Bipolar Next Generation Impactor (bp-NGI).

PURPOSE: To measure the charge to mass (Q/M) ratios of the impactor stage masses (ISM) from commercial Flixotide™ 250 µg Evohaler, containing fluticasone propionate (FP), Serevent™ 25 µg Evohaler, containing salmeterol xinafoate (SX), and a combination Seretide™ 250/25 µg (FP/SX) Evohaler metered dose inhalers (MDIs). Measurements were performed with a purpose built bipolar charge measurement apparatus (bp-NGI) based on an electrostatic precipitator, which was directly connected below Stage 2 of a Next Generation Impactor (NGI). METHODS: Five successive shots of the respective MDIs were actuated through the bp-NGI. The whole ISM doses were electrostatically precipitated to determine their negative, positive and net Q/m ratios. RESULTS: The ISM doses collected in the bp-NGI were shown to be equivalent to those collected in a standard NGI. FP particles, actuated from Flixotide™ and Seretide™ MDIs, exhibited greater quantities of negatively charged particles than positive. However, the Q/m ratios of the positively charged particles were greater in magnitude. SX particles from Serevent™ exhibited a greater quantity of positively charged particles whereas SX aerosol particles from Seretide™ exhibited a greater quantity of negatively charged particles. The Q/m ratio of the negatively charged SX particles in Serevent™ was greater in magnitude than the positively charged particles. CONCLUSIONS: The bp-NGI was used to quantify the bipolar Q/m ratios of aerosol particles collected from the ISMs of commercial MDI products. The positive charge recorded for each of the three MDIs may have been enhanced by the presence of charged ice crystals formed from the propellant during the aerosolisation process.

Development of a Dissolution Method for Gliclazide Modified-Release Tablets Using USP Apparatus 3 with in Vitro-in Vivo Correlation.

Gliclazide (GLZ) is a second generation hypoglycemic drug used for the treatment of Type 2 diabetes mellitus. The low solubility of GLZ has been described as the rate limiting step for drug dissolution and absorption, thus a prediction of its in vivo behavior based on a discriminative dissolution test should lead to a relevant in vitro-in vivo correlation (IVIVC). The aim of this study was to develop a dissolution method for GLZ modified-release (MR) tablets using an United States Pharmacopeia (USP) apparatus 3 through its evaluation by an IVIVC analysis. Various dissolution parameters were evaluated to establish an in vitro method for GLZ tablets. The final dissolution conditions, referred to as method 3, utilized a 400 µm mesh and 30 dips per minute over a total period of 10 h that included 1h in HCl media (pH 1.2), 2h in acetate buffer solution (pH 4.5), 1 h in phosphate buffer solution (PBS; pH 5.8), 5h in PBS (pH 6.8) and finally 1h in PBS (pH 7.2). The calculated point-to-point IVIVC (R2=0.9970) was significantly greater than other methods. The robustness of method 3 suggests it could be applied to pharmaceutical equivalence studies and for quality control analyses of GLZ.

Investigation of the tableting behavior of Ibuprofen DC 85 W.

The aim of the present study was to investigate the tableting behavior of Ibuprofen DC 85 W with special focus on the tablet disintegration time, the tablet crushing strength, and the sticking tendency to punch surfaces. To simulate production conditions, tableting was conducted on a rotary press, equipped with three compaction stations. An I-optimal design of experiments was used to analyze the influence of the pre-compaction, the intermediate compaction, and the main compaction force on the two responses: tablet disintegration time and crushing strength. It was shown that Ibuprofen DC 85 W showed a good tableting behavior with regard to both responses. The tablet disintegration was considerably affected by the maximum compaction force applied, but was also slightly affected by preceding compaction events. The tablet crushing strength was mainly affected by the maximum applied compaction force independent of the order of these forces. The sticking tendency of Ibuprofen DC 85 W was compared with that two other ibuprofen powder formulations in long-term tableting runs. Compared to the other two formulations, sticking was considerably lower with Ibuprofen DC 85 W. The sticking tendency was not influenced by the addition of an intermediate compaction force, but was remarkably reduced by the choice of the punch tip coating.

USP Apparatus 4: a Valuable In Vitro Tool to Enable Formulation Development of Long-Acting Parenteral (LAP) Nanosuspension Formulations of Poorly Water-Soluble Compounds.

Long-acting or extended release parenteral dosage forms have attracted extensive attention due to their ability to maintain therapeutic drug concentrations over long periods of time and reduce administration frequency, thus improving patient compliance. It is essential to have an in vitro release (IVR) testing method that can be used to assure product quality during routine production as well as predict and understand the in vivo performance of a formulation. The purpose of this work was to develop a discriminatory in vitro release method to guide formulation and process development of long-acting parenteral (LAP) nanosuspension formulations composed of poorly water-soluble drugs (BCS class II). Injectable nanosuspension formulations were developed to serve as test articles for method development. Several different IVR methods were evaluated for their application to the formulation screening and process development including (1) USP apparatus 2, (2) dialysis and reverse dialysis sac, and (3) continuous flow-through cell (USP apparatus 4). Preliminary data shows the promising results to support the utilization of USP 4 over more widely accepted USP 2 and dialysis methods. A combination of more representative in vivo hydrodynamics and ease of maintaining sink conditions yields the USP 4 flow-through cell method a more suitable in vitro release method for nanosuspension-based LAP formulations of poorly water-soluble compounds, such as compounds A and B.

Research Progress of Raman Spectroscopy in Drug Analysis.

Raman spectroscopy is a spectroscopic analysis technique that enables rapid qualitative and quantitative detection based on inelastic collision and Raman scattering intensity. This review detailed the generation principle, instrument composition, influencing factors, and common classifications of Raman spectrum. Furthermore, it summarized and forecast the research progress of Raman spectroscopy in the field of drug analysis simultaneously over the past decade, including the identification of active pharmaceutical ingredients (APIs), qualitative and quantitative studies of pharmaceutical preparations, detection of illicit drugs, the identification of Chinese herbal medicines, and the combination with other technologies. The development of Raman spectroscopy in other fields is additionally summarized.