Screening Of Excipients Research Articles

Influence of excipients on thermodynamic phase behavior of pharmaceutical/solvent systems: Molecular thermodynamic model prediction

In this work, the influence of polymeric excipients (PEG6000, PEG400, PVPK25, and HPMCE3) on thermodynamic phase behavior of active pharmaceutical ingredients (API) (mesalazine and allopurinol) and its aqueous solution was systematically investigated through experimental measurement and thermodynamic modeling. The API/excipients formulations were prepared by ball milling, and the phase behavior was measured by differential scanning calorimetry (DSC). The results showed that the solubility of API/solvent systems were all increased with higher temperature. Meanwhile, it was found that all four excipients can solubilize mesalazine and allopurinol effectively and the solubilization performance of PVPK25 and HPMCE3 were preferable to PEG. Furthermore, the thermodynamic phase behavior of API in the excipients/water ternary system was predicted by the Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT), demonstrating good accordance with the experimental results with low average relative deviations (ARDs). This work was expected to provide theoretical guidance for the screening of pharmaceutical formulation excipients.

Formulation Development and Improved Stability of a Combination Measles and Rubella Live-Viral Vaccine Dried for Use in the NanopatchTM Microneedle Delivery System

ABSTRACT Measles (Me) and rubella (Ru) viral diseases are targeted for elimination by ensuring a high level of vaccination coverage worldwide. Less costly, more convenient MeRu vaccine delivery systems should improve global vaccine coverage, especially in low – and middle – income countries (LMICs). In this work, we examine formulating a live, attenuated Me and Ru combination viral vaccine with Nanopatch™, a solid polymer micro-projection array for intradermal delivery. First, high throughput, qPCR-based viral infectivity and genome assays were established to enable formulation development to stabilize Me and Ru in a scaled-down, custom-built evaporative drying system to mimic the Nanopatch™ vaccine coating process. Second, excipient screening and optimization studies identified virus stabilizers for use during the drying process and upon storage in the dried state. Finally, a series of real-time and accelerated stability studies identified eight candidate formulations that met a target thermal stability criterion for live vaccines (<1 log10 loss after 1 week storage at 37°C). Compared to −80°C control samples, the top candidate formulations resulted in minimal viral infectivity titer losses after storage at 2–8°C for 6 months (i.e., <0.1 log10 for Me, and ~0.4 log10 for Ru). After storage at 25°C over 6 months, ~0.3–0.5 and ~1.0–1.4 log10 titer losses were observed for Me and Ru, respectively, enabling the rank-ordering of the stability of candidate formulations. These results are discussed in the context of future formulation challenges for developing microneedle-based dosage forms containing stabilized live, attenuated viral vaccines for use in LMICs.

Exploration of in vitro drug release testing methods for saquinavir microenvironmental pH modifying buccal films

Buccal films containing a pH modifying excipient may be able to increase bioavailability of drugs with pH-dependent solubility such as saquinavir. Access to suitable in vitro drug release testing methods may facilitate buccal formulation development. This study aimed to explore two release testing methods for characterising buccal films and to elucidate the relationship between microenvironmental pH (pHM, i.e. the pH around the swelling films) and saquinavir release. The Franz diffusion cell method was applicable to investigate the effect of hydroxypropyl methylcellulose (HPMC) grade on saquinavir release. Films containing HPMC K3 LV had a faster saquinavir release than films containing HPMC K100 LV. A UV/Vis imaging method was developed to visualise saquinavir release and pHM changes during the initial dissolution. Within 5 min, the pHM decreased from 6.8 to around 5.4 for HPMC K100 LV-based films containing 11.1 % or 16.6 % (w/w) malic acid. Subsequently, the pHM increased due to increasing concentrations of saquinavir. An increase in malic acid content led to a faster saquinavir release. The combination of methods may be broadly applicable for excipient screening in development of buccal formulations. The imaging approach holds promise for characterizing other pH modifying formulation principles.

Monoclonal Antibody Aggregation Associated with Free Radical Induced Oxidation.

Oxidation is an important degradation pathway of protein drugs. The susceptibility to oxidation is a common concern for therapeutic proteins as it may impact product efficacy and patient safety. In this work, we used 2,2′-azobis (2-amidinopropane) dihydrochloride (AAPH) as an oxidative stress reagent to evaluate the oxidation of therapeutic antibodies. In addition to the oxidation of methionine (Met) and tryptophan (Trp) residues, we also observed an increase of protein aggregation. Size-exclusion chromatography and multi-angle light scattering showed that the soluble aggregates induced by AAPH consist of dimer, tetramer, and higher-order aggregate species. Sodium dodecyl sulfate polyacrylamide gel electrophoresis indicated that inter-molecular disulfide bonds contributed to the protein aggregation. Furthermore, intrinsic fluorescence spectra suggested that dimerization of tyrosine (Tyr) residues could account for the non-reducible cross-links. An excipient screening study demonstrated that Trp, pyridoxine, or Tyr could effectively reduce protein aggregation due to oxidative stress. This work provides valuable insight into the mechanisms of oxidative-stress induced protein aggregation, as well as strategies to minimize such aggregate formation during the development and storage of therapeutic proteins.

Synthesis and characterization of a nanoemulsion system for solubility enhancement of poorly water soluble non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) are highly used for the management and treatment of chronic and acute inflammation and to get relief from pain. It consists of a group of organic compounds having anti-inflammatory, anti-pyretic, and analgesic properties. However, majority of these drugs are poorly-water soluble leading to compromised bioavailability and hence limited therapeutic activity. In order to overcome these issues, we have studied the formulation, characterization, and cytotoxicity of NSAIDs, entrapped inside nanoemulsion droplets. NSAIDs-loaded nanoemulsions have been prepared by spontaneous aqueous titration method after the screening of excipients. On the basis of drug solubility study, the mixture of clove oil and isopropyl myristate has been selected as oil phase, whereas Tween 80 and isopropyl alcohol have been used as surfactant and co-surfactant respectively. The hydrodynamic sizes of Diflunisal and Niflumic acid-loaded nanoemulsions obtained from Dynamic Light Scattering (DLS) have been found in the range of 8–22 nm with the polydispersity index (PDI) below 0.5, implying fairly homogenous populations. The transmission electron microscopic (TEM) data supported the DLS results. However, the low zeta potentials of these nanodroplets suggest the formation of metastable nanoemulsions which have been further evaluated by various stress-stability studies. The cytotoxicity assay of the nanoemulsions loaded with poorly water-soluble drugs such as Diflunisal and Niflumic acid holds the promise of improved efficacy when administered via different routes such as oral, transdermal, or local application.

Automated PET-RAFT Polymerization Towards Pharmaceutical Amorphous Solid Dispersion Development.

In pharmaceutical oral drug delivery development, about 90% of drugs in the pipeline have poor aqueous solubility leading to severe challenges with oral bioavailability and translation to effective and safe drug products. Amorphous solid dispersions (ASDs) have been utilized to enhance the oral bioavailability of poorly soluble active pharmaceutical ingredients (APIs). However, a limited selection of regulatory-approved polymer excipients exists for the development and further understanding of tailor-made ASDs. Thus, a significant need exists to better understand how polymers can be designed to interact with specific API moieties. Here, we demonstrate how an automated combinatorial library approach can be applied to the synthesis and screening of polymer excipients for the model drug probucol. We synthesized a library of 25 random heteropolymers containing one hydrophilic monomer (2-hydroxypropyl acrylate (HPA)) and four hydrophobic monomers at varied incorporation. The performance of ASDs made by a rapid film casting method was evaluated by dissolution using ultra-performance liquid chromatography (UPLC) sampling at various time points. This combinatorial library and rapid screening strategy enabled us to identify a relationship between polymer hydrophobicity, monomer hydrophobic side group geometry, and API dissolution performance. Remarkably, the most effective synthesized polymers displayed slower drug release kinetics compared to industry standard polymer excipients, showing the ability to modulate the drug release profile. Future coupling of high throughput polymer synthesis, high throughput screening (HTS), and quantitative modeling would enable specification of designer polymer excipients for specific API functionalities.

Screening of novel excipients for freeze-dried protein formulations

The typical excipients used as bulking agents and lyoprotectants for freeze-drying are usually limited to only a few selected substances, such as sucrose and mannitol. Considering the sheer diversity amongst proteins, it is doubtful that this limited choice should, in every case, provide the best possible option in order to achieve the most stable product. In this work, a screening of 12 proteins with 64 excipients was conducted in order to increase the knowledge space of potential excipients. Three critical quality attributes (CQAs) of the freeze-dried products, namely the solid state, the cake appearance and the protein integrity based on changes in tryptophan fluorescence were investigated by high throughput X-ray powder diffraction, image analysis and intrinsic fluorescence spectroscopy, respectively. It was found, that in some cases the excipient had a dominating influence on the CQAs, whilst in other cases the CQAs were primarily protein dependent, or that the CQAs were dependent on the combination of both. In the course of this investigation, a general view of potentially relevant excipients, and their interplay with various proteins, was obtained, thereby furthermore paving the way for the use of novel freeze-drying excipients.

Development of a fast screening method for selecting excipients in formulations using MD simulations, NMR and microscale thermophoresis

Development of peptide therapeutics generally involves screening of excipients that inhibit peptide-peptide interactions, hence aggregation, and improve peptide stability. We used the therapeutic peptide plectasin to develop a fast screening method that combines microscale thermophoresis titration assays and molecular dynamics simulations to relatively rank the excipients with respect to binding affinity and to study key peptide-excipient interaction hotspots on a molecular level, respectively. Additionally, 1H-13C-HSQC NMR titration experiments were performed to validate the fast screening approach. The NMR results are in qualitative agreement with results from the fast screening method demonstrating that this approach can be reliably applied to other peptides and proteins as a fast screening method to relatively rank excipients and predict possible excipient binding sites.

Amphiphilic Polyacrylamide Excipients Lead to a Record-Breaking Fast-Acting Insulin

Fast-acting insulins are central to the regulation of prandial glucose in diabetic patients. Current fast-acting insulins require 20-30 min for the onset and longer for the peak blood concentrations. The recent work by Mann et al. used high-throughput synthesis and screening of polyacrylamide-based excipients to yield a formulation with pharmacokinetics that is faster than the currently available fast-acting insulins.

P23 Accelerating and de-risking the production of paediatric oral formulations

Background &amp; AimAs part of the EU paediatric regulation, the paediatric use marketing authorisation (PUMA) was introduced, with an aim to stimulate research in existing compounds that are off-patent and/or to help transform known off-label use into authorised use.1 However, success has been limited, with only a few products gaining a PUMA, such as Sialanar 320 micrograms/mL glycopyrronium (equivalent to 400 micrograms/mL glycopyrronium bromide). A distinct challenge to overcome in this area is the development of more ‘age appropriate formulations’, particularly with an excipient composition and load that is suitable for paediatric patients. This project aims to establish an excipient screening platform, supplemented with analytical characterisation of materials, which will act as a decision making tool to accelerate and de-risk the production of age appropriate paediatric medicines.MethodTo develop this excipient screening platform, a list of drugs that require an age appropriate formulation was produced using the ‘needs for paediatric medicines’ documents provided by the European medicines agency (EMA),2whilst common problematic excipients in paediatrics were identified using an EMA reflection paper.3 Literature and prescribing data were also reviewed to ensure drugs selected would benefit from an age appropriate formulation. Differential scanning calorimetry (DSC) to determine compatibility of selected drugs with widely used excipients was carried out using a TA DSCQ200 instrument (TA Instruments, New Castle, DE) with TA Instruments Universal Analysis 2000 software. Data was collected under nitrogen atmosphere (50 mL min−1) using pierced flat-bottomed TZero aluminium pans (sample mass about 2 mg) and heating rate of 10 °C min−1 in the range from 50 to 400°C. For samples containing both the drug and an excipient, 1 mg of each was measured out and gently mixed with a spatula for one minute.ResultsThe most common class of drugs identified as requiring age appropriate formulations were related to cardiovascular disorders and neurology, whilst the majority of drugs identified also exhibit poor aqueous solubilities. Some identified problematic excipients include ethanol, sodium benzoate and sorbitol; however, these excipients may still be used in paediatric formulations, as long as they are below certain concentrations (for example, ethanol concentration should not exceed 0.5% w/v for under 6 years old). Two drugs identified through the initial screening, carvedilol and nifedipine, were analysed by DSC, alone and then alongside starch from corn and starch 1500; the resulting DSC curves showed no changes in peak size, position (peak onset temperatures for nifedipine and carvedilol were observed at 173.2°C and 117.3°C, respectively) and shape, as well as no additional peaks, therefore suggesting compatibility between the tested samples.ConclusionThis first phase of the development of an excipient screening platform will continue to scan several different excipients with selected active pharmaceutical ingredients (APIs) in order to create compatibility profiles. The excipient screening platform generated will accelerate and de-risk the production of age appropriate formulations, as it would allow screening for potential incompatibilities and acceptability, alongside informing formulation of appropriate oral paediatric dosage forms.ReferencesEuropean Commission. State of Paediatric Medicines in the EU. 10 years of the EU Paediatric Regulation. COM (2017) 626. Available at: https://ec.europa.eu/health/sites/health/files/files/paediatrics/docs/2017_childrensmedicines_report_en.pdfNeeds for paediatric medicines - European Medicines Agency [Internet]. 2019 [cited 28 June 2019]. Available from: https://www.ema.europa.eu/en/human-regulatory/research-development/paediatric-medicines/needs-paediatric-medicinesReflection paper: formulations of choice for the paediatric population [Internet]. European Medicines Agency. 2019 [cited 28 June 2019]. Available from: https://www.ema.europa.eu/en/documents/scientific-guideline/reflection-paper-formulations-choice-paediatric-population_en.pdf

The effect of medium chain and long chain triglycerides incorporated in self-nano emulsifying drug delivery systems on oral absorption of cannabinoids in rats.

The aim of this research was to investigate the effect of the lipid component in self-emulsifying drug delivery systems on the oral absorption of major cannabinoids Δ9-tetrahydrocannabinol (THC) and Cannabidiol (CBD). The investigated lipids were either long chain triglycerides (LCT) or medium chain triglycerides (MCT) with different composition, fatty acid chain length, degree of saturation and their absorption pathway to the systemic circulation. Formulations were developed with the purpose of creating thermodynamically stable oil-in-water nano emulsions/suspensions with particle size of 50nm or less which carry the lipophilic drug and increase water solubility. Following a methodic screening of suitable excipients in-vitro, leading formulations based on sesame oil or MIGLYOL® 812N (Type I LCT/MCT SNEDDS) and cocoa butter or tricaprin (Type II LCT/MCT SNEDDS) were investigated in the freely moving rat model. Results in rat model demonstrated that the effect of each type of lipid on bioavailability of cannabinoids is not straightforwardly anticipated. The differences in the effect of LCT and MCT on absorption was not substantial for Type I formulations, however, more prominent for Type II formulations. This unpredictable behavior in-vivo demonstrates the importance of investigating each vehicle pre-clinically, following the in-vitro development.

Characterizing and Minimizing Aggregation and Particle Formation of Three Recombinant Fusion-Protein Bulk Antigens for Use in a Candidate Trivalent Rotavirus Vaccine.

In a companion paper, the structural integrity, conformational stability, and degradation mechanisms of 3 recombinant fusion-protein antigens comprising a non-replicating rotavirus (NRRV) vaccine candidate (currently being evaluated in early-stage clinical trials) are described. In this work, we focus on the aggregation propensity of the 3 NRRV antigens coupled to formulation development studies to identify common frozen bulk candidate formulations. The P2-VP8-P[8] antigen was most susceptible to shaking and freeze-thaw–induced aggregation and particle formation. Each NRRV antigen formed aggregates with structurally altered protein (with exposed apolar regions and intermolecular β-sheet) and dimers containing a non-native disulfide bond. From excipient screening studies with P2-VP8-P[8], sugars or polyols (e.g., sucrose, trehalose, mannitol, sorbitol) and various detergents (e.g., Pluronic F-68, polysorbate 20 and 80, PEG-3350) were identified as stabilizers against aggregation. By combining promising additives, candidate bulk formulations were optimized to not only minimize agitation-induced aggregation, but also particle formation due to freeze-thaw stress of P2-VP8-P[8] antigen. Owing to limited material availability, stabilization of the P2-VP8-P[4] and P2-VP8-P[6] was confirmed with the lead candidate P2-VP8-P[8] formulations. The optimization of these bulk NRRV candidate formulations is discussed in the context of subsequent drug product formulations in the presence of aluminum adjuvants.

A spray freeze dried micropellet based formulation proof-of-concept for a yellow fever vaccine candidate

The stability of live-attenuated viruses is very challenging due to thermal sensitivity; therefore, solid form is usually required (often freeze-dried products). Micropellet technology is a lyophilization technology that has the potential to provide greater flexibility in the presentation of a given vaccine particularly in multi-dose format or in combination of different vaccines. As a novel vaccine alternative process, this spray freeze-dried (SFD) micropellet technology was evaluated using as a model a yellow fever virus produced in Vero cells (vYF).Screening of excipients was performed in order to optimize physico-chemical properties of the micropellets. Sugar/polymer-based formulations induced high glass transition temperature (Tg), adequate breaking force and attrition resistance of the SFD micropellets. These mechanical parameters and their stability are of considerable importance for the storage, the transport but also the filling process of the SFD micropellets. By adding excipients required to best preserve virus infectivity, an optimal sugar/polymer-based formulation was selected to build micropellets containing vYF. Monodisperse and dried micropellets with a diameter of about 530 µm were obtained, exhibiting similar potency to conventional freeze-dried product in terms of vYF infectious titer when both solid forms were kept under refrigerated conditions (2–8 °C). Comparable kinetics of degradation were observed for vYF formulated in micropellets or as conventional freeze-dried product during an accelerated stability study using incubations at 25 °C and 37 °C over several weeks. The results from this investigation demonstrate the ability to formulate live-attenuated viruses in micropellets. Pharmaceutical applications of this novel vaccine solid form are discussed.

Enhancement in Dissolution Rate of Atorvastatin Trihydrate Calcium by Formulating Its Porous Tablet Using Sublimation Technique

Proposed study was aimed to formulate and evaluate atorvastatin trihydrate calcium porous tablet. Since atorvastatin trihydrate calcium is highly unstable drug and is immensely susceptible to hydrolysis and oxidation process, sublimation technique is taken into account for preparing porous tablet by using direct compression technique. Excipient screening and pre-formulation study was conducted to evaluate the presence of drug-excipient compatibility. Formulation was optimised using central composite design (CCD) and optimized batch was further characterised by scanning electron microscopy (SEM) for identification of surface topography. Optimized formulation was also characterised with respect to FTIR, TGA analysis, compression analysis, in vitro drug release studies and stability studies. Hardness, friability, disintegration time and drug content of optimized porous tablets were found to be 3.46 kg/cm2, 0.92%, 7.23 s and 97.00%, respectively. Compression analysis showed optimized formulation powder is soft and plastic in nature. Tensile strength studies revealed that the tensile strength increases with increase in compression pressure. SEM studies confirmed the presence of number of pores with less than 10 μm pore size. FTIR and TGA studies confirmed that there is no change in chemical structure of drug even in porous tablet. Prepared porous tablets released 85.06 ± 15.55% of drug in 25 min whereas immediate release marketed tablets and pure drug released only 59.13 ± 4.78% and 11.36 ± 2.90% of drug in a same time. The release of proposed dosage form was substantially greater than the marketed product. Preliminary profile of stability studies did not show any significant change (p > 0.05) in the results after 90 days. Porous tablets improved release rate which confirmed that this approach may be useful to enhance the dissolution rate of atorvastatin trihydrate calcium.

Insights on role of polymers in precipitation of celecoxib from supersaturated solutions as assessed by focused beam reflectance measurement (FBRM)

Supersaturating drug delivery systems (SDDS) have dominated the commercial and academic spheres owing to their potential in overcoming the solubility issue of poorly soluble drugs. Precipitation inhibitors are used as excipients in such formulations which has necessitated the development of supersaturation assays that evaluate their precipitation-inhibition efficacy. Such assays are able to give relative estimates of polymer efficacy ceteris paribus within a given set-up. However, the estimates of different laboratories cannot be compared with each other owing to high variability in procedure. Microarray plate method allows comprehensive replicates and decent statistics that make the method an edge over the other exploratory assays. In the current study, the precipitation-inhibition performance of three polymers on the precipitation of a model BCS class II drug was evaluated using the microarray plate method. Quantitative estimations were made through application of Poisson equation for nucleation rates and area under curve. Insights of the precipitation process at particle level were obtained through focused beam reflectance measurement (FBRM) technique coupled with end-process PVM imaging. Through real-time particle size analysis, FBRM technique demonstrated the potential for discerning the role of polymer as nucleation-inhibitor or crystal growth inhibitor. The events observed in the scaled-up FBRM analysis could be correlated with the events observed visually and spectrophotometrically. Powder X-ray diffraction and scanning electron microscopy were performed to capture the influence of polymers on the precipitates formed. This study was able to demonstrate the applicability of microarray plate method for quantitative estimations of precipitation kinetics that can be utilized for excipient screening for poorly soluble drugs having intra-luminal precipitation as a problem. FBRM analysis is highly valuable to gain mechanistic insights and put to rest the prevalent conjecture-based role attribution for polymers.

A Relative Permittivity Approach for Fast Drug Solubility Screening of Solvents and Excipients in Lipid-Based Delivery

Drug solubility screening in solvents and lipids is central for the development of lipid-based formulations (LBFs), and any guidance to reduce the experimental workload would be highly desirable. Solubility parameters are interesting as they can be predicted in silico for a drug but they are hardly predictable for complex lipids. This paper uses a new approach to convert an in silico drug solubility parameter to an estimated relative permittivity, εr. Diverse solvents and lipid-based excipients were then experimentally tested for εr and solubility using fenofibrate as model. The typical excipients and solvents used in LBFs showed an εr range of about 2-24, and good solubility of fenofibrate was indeed evidenced in vicinity of its estimated relative permittivity 13.2 ± 2.7. Mixtures of promising excipients were studied subsequently, and the obtained εr was predictable based on the known values of the individual components. The novel permittivity approach has demonstrated its usefulness, it has much potential in early development for ranking of suitable excipients, and it gives an initial orientation to design formulations. Future research may clarify further opportunities and limits of the novel approach for LBFs.

Stabilised aluminium phosphate nanoparticles used as vaccine adjuvant

Aluminium phosphate is a commonly used adjuvant consisting of heterogeneously sized aggregates up to several micrometers. However, aluminium phosphate nanoparticles may exhibit an improved adjuvant effect. In this study, nanoparticles were made by sonication of commercially available aluminium phosphate adjuvant, resulting in particles with a size (Z-average diameter) between 200–300 nm and a point of zero charge of 4.5. To prevent reaggregation, which occurred within 14 days, a screening of excipients was performed to identify stabilisers effective under physiological conditions (pH 7.4, 290 mOsm). The amino acids threonine, asparagine, and L-alanyl-L-1-aminoethylphosphonic acid (LAPA) stabilised sonicated aluminium phosphate. Particle sizes remained stable between 400–600 nm at 37 °C during 106 days. Contrarily, arginine induced strong reaggregation to a particle size larger than 1000 nm. The stability of aluminium phosphate nanoparticles was strongly affected by the pH. Aggregation mainly occurred below pH 7. The adsorption capacity, a potentially relevant parameter for adjuvants, was slightly reduced in the presence of asparagine, when using a model antigen (lysozyme). LAPA, arginine, threonine and aspartic acid reduced protein adsorption significantly. The adjuvant effect of aluminium phosphate nanoparticles was studied by immunisation of mice with diphtheria toxoid adjuvanted with the aluminium phosphate nanoparticles. The presence of LAPA, threonine, aspartic acid or asparagine did not alter diphtheria toxoid-specific antibody or toxin-neutralising antibody titres. Arginine increased diphtheria toxoid-specific antibody titres but not toxin-neutralising antibody titres. In conclusion, aluminium phosphate nanoparticles were stabilised by particular amino acids and induced an adjuvant effect comparable to that of aluminium phosphate microparticles.

Screening of Sacrificial Excipients for Arresting Devitrification of Itraconazole from Solid Dispersion.

The aim of the present investigation was to develop a solid dispersion of itraconazole (ITR) using sacrificial excipients like pregelatinized starch and spray-dried lactose alongside hydroxypropyl methylcellulose and Poloxamer 188, thereby arresting the conversion of the amorphous form of ITR to crystalline form, and to assess the dissolution stability of an amorphous form of the drug during short-term storage. ITR-loaded solid dispersions were prepared by kneading. Formulation optimization was achieved by using a 24 full factorial design on the basis of cumulative percent drug released at t30, t60, and t120 min. An artificial neural network (ANN) was also applied as a statistical tool for obtaining better predictive ability and the outcomes of the ANN were compared with that of Design-Expert software. The spectral data revealed no drug-carrier interactions. The P-X-ray diffraction study of the optimized batch showed a decrease in the crystallinity of drug as compared to the untreated drug. The in vitro dissolution studies of the optimized batch showed higher dissolution (92% at 120 min) in comparison to the other formulations. The dissolution stability study was performed at 40°C and 75% relative humidity for 90 days for the optimized formulation. The results of the optimized batch showed insignificant changes in cumulative percentage drug release during storage. Dissolution stability could be attributed to the presence of sacrificial excipients as they tend to absorb moisture during storage and possibly get converted into crystalline form, thereby minimizing the recrystallization of ITR.

Systematic development of a high dosage formulation to enable direct compression of a poorly flowing API: A case study

In this work, the transfer of oral solid dosage forms, currently manufactured via wet granulation, to a continuous direct compression process was considered. Two main challenges were addressed: (1) a poorly flowing API (Canagliflozin) and (2) high drug loading (51 wt%). A scientific approach was utilised for formulation development, targeting flow and compaction behaviour suitable for manufacturing scale. This was achieved through systematic screening of excipients to identify feasible formulations. Targeted design of experiments based on factors such as formulation mixture and processing parameters were utilised to investigate key responses for tablet properties, flow and compaction behaviour. Flow behaviour was primarily evaluated from percentage compressibility and shear cell testing on a powder flow rheometer (FT4). The compaction behaviour was studied using a compaction simulator (Gamlen). The relationships between tablet porosity, tensile strength and compaction pressure were used to evaluate tabletability, compactibility and compressibility to assess scale-up. The success of this design procedure is illustrated by scaling up from the compaction simulator to a Riva Piccola rotary tablet press, while maintaining critical quality attributes (CQAs). Compactibility was identified as a suitable scale-up relationship. The developed procedure should allow accelerated development of formulations for continuous direct compression.

Investigating the effect of transcutol on the physical properties of an O/W cream

Topical cream product development typically requires screening of excipients and emulsifiers to kinetically stabilize otherwise thermodynamically metastable systems. The conventional concepts of hydrophilic-lipophilic balance for selecting emulsifiers often work with mixtures of oil and water phases. However, in the presence of polar organic solvents, other methodologies must be employed for formulation selection during the development process. This work demonstrates how tensiometry can be used along with other characterization techniques to elucidate failure mechanisms in oil in water (O/W) creams. Emulsion systems were prepared with varying amounts of the co-solvent, Transcutol® P (TP). Physical characterization by optical microscopy, LUMiSizer® and DSC identified a critical concentration of Transcutol® P (>25 wt. %) at which the microstructure, melting temperature, and relative stability of the cream changed significantly. Interfacial tension (IFT) values were also found to decrease with increasing amount of Transcutol® P in the absence of emulsifiers, indicating an increase in miscibility and the formation of a one phase system. At higher levels of Transcutol® P (40% w/w), decreasing the emulsifier content did not reduce droplet size. These experiments demonstrated that a minimum inherent immiscibility between the emulsion phases in the absence of emulsifiers is required for a stable two-phase emulsion system. We show here how the stability of a complex, polar oil – polar solvent emulsion can be determined by a combination of factors including droplet size/distribution, melting temperature, apparent viscosity, and IFT.