Application of Multivariate Methods to Evaluate the Functionality of Bovine- and Vegetable-Derived Magnesium Stearate

Optimized L-SNEDDS and spray-dried S-SNEDDS using a linked QbD-DM3 rational design for model compound ketoprofen

A QbD-DM³ strategy was used to design ketoprofen (KTF) optimized liquid (L-SNEDDS) and solid self-nanoemulsifying drug delivery systems (S-SNEDDS). Principal component analysis was used to identify the optimized L-SNEDDS containing Capmul® MCM NF, 10 % w/w; Kolliphor® ELP, 60 % w/w; and propylene glycol, 30 % w/w. The S-SNEDDS was manufactured by spray-drying a feed dispersion prepared by dissolving the optimized KTF-loaded L-SNEDDS in an ethanol-Aerosil® 200 dispersion. A Box Behnken design was employed to evaluate the effect of drug concentration (DC), Aerosil® 200 concentration (AC) and feed rate (FR) on maximizing percent yield (PY) and loading efficiency (LE). The optimal levels of DC, AC, and FR were 19.9 % w/w, 30.0 % w/w, and 15.0 %, respectively. The optimized S-SNEDDS was amorphous, and its dissolution showed a 2.37-fold increase in drug release compared to KTF in 0.1 HCl. An optimized independent spray-dried S-SNEDDS verification batch showed that the predicted and observed PY and LE were 70.49 % and 92.49 %, and 70.02 % and 91.27 %, respectively. The optimized L-SNEDDS and S-SNEDDS also met their quality target product profile criteria for globule size <100 nm, polydispersity index < 0.400, emulsification time < 30 s, and KTF L-SNEDDS solubility 100-fold greater than its water solubility.

Leveraging the Exploratory and Predictive Capabilities of Design of Experiments in Development of Intraarticular Injection of Imatinib Mesylate Containing Lipospheres

An intraarticular, liposphere-based, formulation of Imatinib mesylate for weekly administration was developed. Lipospheres were prepared using double emulsion technique using dierucoyl phosphatidylcholine, 1,2-dipalmitoyl-sn-glycero-3-phospho-rac-(1-glycerol) sodium salt), cholesterol, and tricaprylin as lipid phase in dichloromethane in a four-step process. Primary emulsion, formed using a high-pressure homogenizer, was diluted using a secondary aqueous phase in an Inline mixer to form the liposomal dispersion. Nitrogen flushing was done to remove dichloromethane, and the dispersion was finally centrifuged and adjusted for potency. The amount of cholesterol and triglyceride was taken as formulation variables, and speed of homogenization was used as a process variable in the Box-Behnken design while particle size, % drug entrapment, and drug release at the end of 4 h and 5 days were taken as response variables. Multivariate data analysis grouped the variables in two latent variable sets, one based on the speed and the other on the composition of lipospheres. Multiple linear regression analysis was used to generate mathematical model for each response. Constraints were put on the values of responses, as per the requirements of the final product, and the "freedom to operate" design space was located using an overlay plot. The center point batch sufficed all the set criteria, and Monte Carlo simulations on the factor variables indicated a defect rate of 5%. The center point batch was characterized for viscosity, osmolality, pH, drug release, and lipocrit value. The dispersion was charged in a prefilled syringe and studied for stability. The product was found to be stable at 2-8°C over a period of 6 months.

Investigation into powder tribo-charging of pharmaceuticals. Part II: Sensitivity to relative humidity

Environmental conditions can have a profound impact on the bulk behaviour of pharmaceutical powders, including their tribo-charging tendency. Typically, high relative humidity (RH) has been associated to a reduction in the electrostatic charge of the material. However, the occurrence of charge mitigation seems to be related to the quantity of water molecules at the powder surface, which depends on intrinsic material attributes (i.e., water sorption propensity), and external factors (i.e., RH level). In the present study, pharmaceutical powders (i.e., microcrystalline cellulose, D-mannitol, paracetamol and magnesium stearate) were conditioned at three levels of RH, relevant for pharmaceutical operations, and their bulk behaviour, including charging propensity, was analyzed. Depending on the material type, powders sorbed water from the humid atmosphere to different extents, resulting in different charging behaviours. Overall, the charge density of the materials was found to decrease after a certain RH or monotonically decrease with an increase of RH, except for D-mannitol. For this material, a contrasting trend of increase in charging was observed with an increase in RH. Moreover, the powders showed a distinct tribo-charging sensitivity to RH, with paracetamol being the most affected. These findings suggest that a careful consideration on solid material-moisture interactions is needed when using RH as strategy to minimize electrostatic effects in powder processing.

Hybridized nanoamorphous micellar dispersion using a QbD-DM3 linked rational product design strategy for ritonavir: A BCS IV drug

A QbD-DM³ linked rational product design strategy was adopted to create a hybridized ritonavir (RTV, BCS Class IV) nanoamorphous micellar dispersion (RTV-NAD). A DM³ research strategy was employed in conjunction with the quality-by-design spaces, and quality target product profile to link the critical material attributes and critical process parameters to the quality target product profile's critical product attributes QbD elements. A Box-Behnken design and multivariate analysis using multiple linear regression and partial least squares provided data analysis. The hybridized strategy leveraged three different mechanisms to increase RTV's solubility and four mechanisms to increase its dissolution rate. Statistically significant models were generated for critical product attributes: particle size (p = 0.0000, R² adjusted = 0.9513), polydispersity index (p = 0.0002, R² adjusted = 0.6398), zeta potential (p = 0.0000, R² adjusted = 0.9744), and drug loading on a dry basis (p = 0.0000, R² adjusted = 0.9951). The impact of drug concentration, Soluplus® concentration, and solvent:antisolvent ratio, their interactions and square effects on the critical product attributes were assessed by multivariate analysis. The QbD optimal formulation was determined for RTV-NAD. Multiple linear regression and partial least squares computational predictability was evaluated using three verification batches. The prediction error for critical product attributes was <5%. RTV-NAD and ritonavir microsuspension were characterized by x-ray diffraction and in-vitro dissolution studies. X-ray diffraction confirmed the amorphous nature of the RTV-NAD. RTV-NAD exhibited a 'spring-hover' dissolution profile at pH 4.5. At pH 6.8, a classic 'spring-parachute' dissolution behavior was observed.

Employing Multivariate Statistics and Latent Variable Models to Identify and Quantify Complex Relationships in Typical Compression Studies

The effect of storage condition (% RH) on flufenamic acid:nicotinamide (FFA:NIC) cocrystal compressibility, compactibility, and tabletability profiles was not observed after visual evaluation or linear regression analysis. However, multivariate statistical analysis showed that storage condition had a significant effect on each compressional profile. Shapiro and Heckel equations were used to determine the compression parameters: porosity, Shapiro's compression parameter (f), densification factor (Da), plastic yield pressure (YPpl), and elastic yield pressure (YPel). Latent variable models such as exploratory factor analysis, principal component analysis, and principal component regression were employed to decode complex hidden main, interaction, and quadratic effects of % RH and the compression parameters on FFA:NIC tablet mechanical strength (TMS). Statistically significant correlations between f and Da, f and YPpl, and Da and YPel supported the idea that both rearrangement and fragmentation, and plastic deformation are important to FFA:NIC TMS. To the authors knowledge, this is the first time that simultaneously operating dual mechanisms of fragmentation and plastic deformation in low and midrange compression, and midrange plastic deformation have been identified and reported. A quantitative PCR model showed that f, Da, and YPel had statistically significant main effects along with a significant antagonist storage condition-porosity "conditional interaction effect". f exhibited a 2.35 times greater impact on TMS compared to Da. The model root-mean-square error at calibration and prediction stages were 0.04 MPa and 0.08 MPa, respectively. The R² values at the calibration stage and at the prediction stage were 0.9005 and 0.7539, respectively. This research demonstrated the need for caution when interpreting the results of bivariate compression data because complex latent inter-relationships may be hidden from visual assessment and linear regression analysis, and result in false data interpretation as illustrated in this report.

Impact of Magnesium Stearate Presence and Variability on Drug Apparent Solubility Based on Drug Physicochemical Properties

Excipients are major components of oral solid dosage forms, and changes in their critical material attributes (excipient variability) and/or amount (excipient variation) in pharmaceutical formulations may present a challenge for product performance. Understanding the biopharmaceutical factors affecting excipient performance is recommended for the successful implementation of excipient variability on Quality by Design (QbD) approaches. The current study investigated the impact of magnesium stearate (MgSt) variability on the apparent solubility of drugs with a wide range of physicochemical properties (drug ionization, drug lipophilicity, drug aqueous solubility). Compendial and biorelevant media were used to assess the role of gastrointestinal (GI) conditions on the excipient effects on drug apparent solubility. The lipophilic nature of MgSt decreased the apparent solubility of most compounds. The reduction in drug apparent solubility was more pronounced for highly soluble and/or highly ionized drugs and in presence of more highly crystalline or smaller particle size MgSt. The use of multivariate data analysis revealed the critical physicochemical and biopharmaceutical factors and the complex nature of excipient variability on the reduction in drug apparent solubility. The construction of a roadmap combining drug, excipient and medium characteristics allowed the identification of the cases where the presence of excipient or excipient variability may present risks for oral drug performance.

Tablet capping predictions of model materials using multivariate approach

The present study demonstrated the prediction of predominant root causes of capping behavior as a function of the powder rheological and the mechanical behavior of Acetaminophen (APAP) and Ibuprofen (IBU). The authors analyzed powder rheological properties for powder blend permeability, pressure drop, and cohesion. The measured deformation properties were compact porosity, internal air pressure, Brinell hardness, and tensile strength. The data were evaluated qualitatively and quantitatively using multivariate techniques, such as principal component analysis (PCA) and principal component regression (PCR) models, respectively, to identify the effect of powder air entrapment efficiency and mechanical behavior on the tablet capping score. The PCA model indicated that pressure drop, cohesion, API amount, and compression pressure correlated positively, whereas permeability, porosity, internal air pressure, Brinell hardness, and tensile strength correlated negatively to the capping potential. APAP and IBU also showed two independent mechanisms as a function of their amount on the capping score at all compression pressures. APAP and IBU followed an exponential and linear relationship, respectively. Furthermore, the dominant powder rheological and deformation behavior affecting the capping score of each material was identified and quantified using two separate PCR models. These models showed that APAP capping was predominantly dependent on its powder properties, while that of IBU was predominantly based on its deformation properties. In conclusion, APAP and IBU compacts capping had respective air induced and deformation induced capping behavior. The proposed approach can aid in understanding the underlying mechanisms of capping and developing an effective, optimized strategy to ensure tablet quality.

Enhanced Understanding of Pharmaceutical Materials Through Advanced Characterisation and Analysis

The impact of pharmaceutical materials properties on drug product quality and manufacturability is well recognised by the industry. An ongoing effort across industry and academia, the Manufacturing Classification System consortium, aims to gather the existing body of knowledge in a common framework to provide guidance on selection of appropriate manufacturing technologies for a given drug and/or guide optimization of the physical properties of the drug to facilitate manufacturing requirements for a given processing route. Simultaneously, material scientists endeavour to develop characterisation methods such as size, shape, surface area, density, flow and compactibility that enable a stronger understanding of materials powder properties. These properties are routinely tested drug product development and advances in instrumentation and computing power have enabled novel characterisation methods which generate larger, more complex data sets leading to a better understanding of the materials. These methods have specific requirements in terms of data management and analysis. An appropriate data management strategy eliminates time-consuming data collation steps and enables access to data collected for multiple methods and materials simultaneously. Methods ideally suited to extract information from large, complex data sets such as multivariate projection methods allow simpler representation of the variability contained within the data and easier interpretation of the key information it contains. In this review, an overview of the current knowledge and challenges introduced by modern pharmaceutical material characterisation methods is provided. Two case studies illustrate how the incorporation of multivariate analysis into the material sciences workflow facilitates a better understanding of materials.

Deciphering magnesium stearate thermotropic behavior

Magnesium stearate (MgSt) is the most commonly used excipient for oral solid dosage forms, yet there is significant commercial physicochemical variability that can lead to variable performance of critical product attributes. Differential scanning calorimetry (DSC) is often used as a quality control tool to characterize MgSt, but little data is available regarding the physicochemical relevance for the DSC thermograms. The main aim of this study was to decipher MgSt's complex thermotropic behavior using DSC, thermogravimetric analysis, capillary melting point, polarized hot-stage microscopy, and temperature dependent small-angle X-ray scattering (SAXS) and assign physicochemical relevance to the DSC thermograms. Several DSC thermal transitions are irreversible after the first heating cycle of a heat-cool-heat-cool-heat cycle. Interestingly, after the first heat cycle, the complex cool-heat-cool-heat DSC thermograms were highly reproducible and exhibited 6 reversible exothermic-endothermic conjugate pairs. SAXS identified 5 distinct mesophases at different temperatures with Phase C' persisting to 250 °C. MgSt maintained molecular ordering beyond 276 °C and did not undergo a simple melting phenomena reported elsewhere. This research serves as a starting point to design heat-treatment strategies to create more uniform MgSt starting material.

Identification of beagle food taking patterns and protocol for food effects evaluation on bioavailability

Food is a known primary role to the exposure of the drugs orally administered. Since each animal may have unique food taking pattern and it is difficult to manipulate the food taking to animals, there lacks rationalized protocol for the food effects in pre-clinic study. The objective of this study was to identify the beagle food taking patterns and demonstrate their effects on bioavailability in valsartan. Herein, four types of food taking patterns of beagle were identified via inter-day and intra-day analysis, and named as Persisting, Pulsing, Postponing, Pushing (“4P Modes”), respectively, which were also validated by principal component analysis (PCA). Interestingly, food intake resulted in a reduced area under the concentration-time curve (AUC_0–12h), maximum concentration (C_max) and absorption rate, whilst the reduction varied in “4P Modes” of food taking. General considerations in the design of experiment for food effect to the bioavailability in beagles have been established as: to recognize the food taking patterns in each animal, to confirm the inter-day stability of the food taking behaviors, to trace the food taking patterns in parallel with plasma sampling. In conclusion, the right animals with proper food taking patterns should be assessed and selected for pre-clinic bioavailability evaluations.

Dipalmitoylphosphatidylcholine (DPPC): Annealing Strategy to Mitigate Variability in Thermotropic and Moisture Sorption Behavior

Dipalmitoylphosphatidylcholine (DPPC) demonstrated complex differential scanning calorimetry (DSC) thermal behavior. Transitions below 100°C showed variability in their thermotropic reversibility. An experimental design employing a DSC heat-cool-heat-cool-heat cycle and modulated DSC were used to gain insight into the DPPC's complex thermal nature. An annealing strategy was developed to reduce DPPC's thermotropic variability, moisture uptake rate, and rate variability. Samples annealed at 110°C for 5 min provided a reproducible, thermally reversible material. The annealed material also exhibited an 8-fold decrease in moisture sorption rate and a statistically significant (p = 0.0233) 100-fold decrease in water sorption rate variability compared to DPPC "as is." An optimized validated stability-indicating high performance liquid chromatography with evaporative light scattering detection method was developed and showed no change in DPPC chemical stability under the annealing treatment conditions.

Investigation into the Manufacture and Properties of Inhalable High-Dose Dry Powders Produced by Comilling API and Lactose with Magnesium Stearate

The aim of the study was to understand the impact of different concentrations of the additive material, magnesium stearate (MGST), and the active pharmaceutical ingredient (API), respectively, on the physicochemical properties and aerosol performance of comilled formulations for high-dose delivery. Initially, blends of API/lactose with different concentrations of MGST (1-7.5% w/w) were prepared and comilled by the jet-mill apparatus. The optimal concentration of MGST in comilled formulations was investigated, specifically for agglomerate structure and strength, particle size, uniformity of content, surface coverage, and aerosol performance. Secondly, comilled formulations with different API (1-40% w/w) concentrations were prepared and similarly analyzed. Comilled 5% MGST (w/w) formulation resulted in a significant improvement in in vitro aerosol performance due to the reduction in agglomerate size and strength compared to the formulation comilled without MGST. Higher concentrations of MGST (7.5% w/w) led to reduction in aerosol performance likely due to excessive surface coverage of the micronized particles by MGST, which led to failure in uniformity of content and an increase in agglomerate strength and size. Generally, comilled formulations with higher concentrations of API increased the agglomerate strength and size, which subsequently caused a reduction in aerosol performance. High-dose delivery was achieved at API concentration of >20% (w/w). The study provided a platform for the investigation of aerosol performance and physicochemical properties of other API and additive materials in comilled formulations for the emerging field of high-dose delivery by dry powder inhalation.

A two-step approach for fluidized bed granulation in pharmaceutical processing: Assessing different models for design and control

Various modeling techniques were used to understand fluidized bed granulation using a two-step approach. First, Plackett-Burman design (PBD) was used to identify the high-risk factors. Then, Box-Behnken design (BBD) was used to analyze and optimize those high-risk factors. The relationship between the high-risk input variables (inlet air temperature X1, binder solution rate X3, and binder-to-powder ratio X5) and quality attributes (flowability Y1, temperature Y2, moisture content Y3, aggregation index Y4, and compactability Y5) of the process was investigated using response surface model (RSM), partial least squares method (PLS) and artificial neural network of multilayer perceptron (MLP). The morphological study of the granules was also investigated using a scanning electron microscope. The results showed that X1, X3, and X5 significantly affected the properties of granule. The RSM, PLS and MLP models were found to be useful statistical analysis tools for a better mechanistic understanding of granulation. The statistical analysis results showed that the RSM model had a better ability to fit the quality attributes of granules compared to the PLS and MLP models. Understanding the effect of process parameters on granule properties provides the basis for modulating the granulation parameters and optimizing the product performance at the early development stage of pharmaceutical products.

Statistical Optimization of Evaporative Light Scattering Detection for Molten Sucrose Octaacetate and Comparison With Ultraviolet Diode Array Detection Validation Parameters Using Tandem HPLC Ultraviolet Diode Array Detection/Evaporative Light Scattering Detection-Specific Stability-Indicating Method

A sucrose octaacetate (SOA) gradient HPLC evaporative light scattering detection (ELSD) and low-wavelength UV-diode array detection (UV-DAD)-specific stability-indicating method development and validation comparison is reported. A central composite response surface design and multicriteria optimization was used to maximize molten SOA area-under-the-curve response and signal-to-noise ratio. The ELSD data were also analyzed using multivariate principal component analysis, analysis of variance, and standard least squares effects modeling. The method suitability and validation parameters of both methods were compared. To the authors' knowledge, this is the first report that validates an ELSD method using a molten analyte. SOA exhibited a low molar absorptivity of 439 absorption units/cm/M in water at 210 nm requiring low-wavelength UV-DAD detection. The low-wavelength UV-DAD method provided substantially better intraday and interday precision, intraday and interday goodness-of-fit, detection limit, and quantitation limit than ELSD. ELSD exhibited a 60-fold greater area-under-the-curve response, better resolution, and 58% more theoretical plates. On balance, the UV-DAD method was chosen for SOA chemical kinetic studies. This study illustrates that ELSD may not always be the best alternative to gradient HPLC low-wavelength UV detection.

Impact of moisture and magnesium stearate functionality on manufacturability of wet granulated metformin tablets

During the development of a wet granulated 850 mg metformin hydrochloride tablet formulation, the tablets exhibited high friability (>3% w/w) irrespective of the source of extra-granular magnesium stearate (MgSt). High friability values indicated that an anti-bonding effect of MgSt was too high to be overcome by 3.3% w/w povidone as a binder in the formulation with 1.5% w/w residual granule moisture. Increasing the povidone concentration up to 7% w/w showed limited improvement in friability, with tablets showing variable friability depending on MgSt source. Characterization of MgSt indicated differences in crystallinity, surface area and particle morphology between different vendors. In addition, a new bulk yield strength test, which determines the MgSt fragmentation tendency, was found to be indicative of the MgSt performance in the tablet formulation. To improve bonding properties of granules, residual granule moisture was increased to 2% w/w at different povidone concentrations. At 2% w/w residual granule moisture content, regardless of MgSt source, the tablets showed significant improvement in friability (∼0.6% w/w) even at the lowest povidone concentration (3.3% w/w). The bonding power of higher residual granule moisture had a greater impact than higher povidone concentration in overcoming the anti-bonding effects of magnesium stearate.