Critical Tools in Tableting Research: Using Compaction Simulator and Quality by Design (QbD) to Evaluate Lubricants' Effect in Direct Compressible Formulation.

As commonly known, the product development stage is quite complex, requires intensive knowledge, and is time-consuming. The selection of the excipients with the proper functionality and their corresponding levels is critical to drug product performance. The objective of this study was to apply quality by design (QbD) principles for formulation development and to define the desired product quality profile (QTPP) and critical quality attributes (CQA) of a product. QbD is a risk- and science-based holistic approach for upgraded pharmaceutical development. In this study, Ibuprofen DC 85W was used as a model drug, Cellactose® 80 along with MicroceLac® 100 as a filler, and magnesium stearate, stearic acid, and sodium stearyl fumarate as lubricants. By applying different formulation parameters to the filler and lubricants, the QbD approach furthers the understanding of the effect of critical formulation and process parameters on CQAs and the contribution to the overall quality of the drug product. An experimental design study was conducted to determine the changes of the obtained outputs of the formulations, which were evaluated using the Modde Pro 12.1 statistical computer program that enables optimization by modeling complex relationships. The results of the optimum formulation revealed that MicroceLac® 100 was the superior filler, while magnesium stearate at 1% was the optimum lubricant. A design space that indicates the safety operation limits for the process and formulation variables was also created. This study enriches the understanding of the effect of excipients in formulation and assists in enhancing formulation design using experimental design and mathematical modeling methods in the frame of the QbD approach.

Synthesis, Characterizations, and Use of O-Stearoyl Mannose Ligand-Engineered Lipid Nanoarchitectonics for Alveolar Macrophage Targeting.

The main challenging aspect in the management of tuberculosis (TB) diseases is effective alveolar macrophages targeting. Macrophage mannose receptor plays a predominant role in stimulating immune systems by TB pathogen. Our earlier in silico computational studies revealed that O-stearoyl mannose (OSM) possesses a higher affinity with macrophage mannose receptors. Therefore, keeping this in view, we developed OSM with the association of stearic acid and d-mannose as initial reactants by the esterification process. Preliminary confirmation of reaction was assessed with thin-layer chromatography experimentation, whereas further confirmation followed by in vitro characterization with several analytical experimental tools such as fourier transform near-infrared, differential scanning calorimetry, and electrospray ionization-assisted mass spectrometry confirms the formation of the OSM. This synthesized and well-characterized OSM as a ligand was further incubated with surface-engineered lipid nanoarchitectonics to achieve OSM ligand-engineered lipid nanoarchitectonics and earlier explored for its safety study through hemolysis assay and potential in vitro triggering efficiency in human alveolar macrophages (THP-1 cells) to validate its active targeting efficiency. Graphical Abstract [Figure: see text].

A novel approach to avoid capping and/or lamination by application of external lower punch vibration.

Capping as well as lamination are two common problems, which affect the resulting product quality of the tablet. Usually, capping and lamination occur during or after tablet manufacturing, and may therefore influence follow-up processes such as the coating. In this context, there is an urgent need for approaches to overcome the occurrences of capping and lamination. In the present study, a novel lower punch vibration technique was used to decrease the capping or lamination tendency of different powder formulations. Different microcrystalline cellulose types, as well as an API (acetaminophen), were selected as model powders. The powders were investigated regarding their powder flow, density, particle morphology, and surface area. Moreover, the manufactured tablets were characterized regarding their tablet weight, tensile strength, and capping or lamination indices. It was shown that the capping or lamination tendency was strongly affected by the physical powder properties, the formulation composition, and the adjusted turret speed. In addition, the application of externally applied lower punch vibration led to a pronounced decrease of the capping or lamination tendency and improved mechanical stability of the manufactured tablets.

Synthesis of 9-Hydroxystearic Acid Derivatives and Their Antiproliferative Activity on HT 29 Cancer Cells.

9-Hydroxystearic acid (9-HSA) is an endogenous cellular lipid that possesses antiproliferative and selective effects against cancer cells. A series of derivatives were synthesized in order to investigate the effect of the substituent in position 9 and on the methyl ester functionality on the biological activity. The two separate enantiomers of methyl 9-hydroxystearate and of methyl 9-aminostearate showed antiproliferative activity against the HT29 cell line. This indicates the importance of position 9 groups being able to make hydrogen bonding with the molecular target. Further, this effect must be preserved when the carboxy group of 9-HSA is esterified. The biological tests showed that the amines, contrarily to methyl esters, resulted in cytotoxicity. A deep investigation on the effect of methyl (R)-9-hydroxystearate on HT29 cells showed an antiproliferative effect acting through the CDKN1A and MYCBP gene expression.

Improving breast cancer therapy using doxorubicin loaded solid lipid nanoparticles: Synthesis of a novel arginine-glycine-aspartic tripeptide conjugated, pH sensitive lipid and evaluation of the nanomedicine in vitro and in vivo.

Breast cancer is the leading cause of cancer mortality in women worldwide. To overcome the toxic side effects and multidrug resistance (MDR) during doxorubicin (DOX) chemotherapy, an arginine-glycine-aspartic (RGD) tripeptide modified, pH-sensitive solid lipid nanoparticles (SLNs) is employed in this study. In this study, a RGD conjugated, pH sensitive lipid was synthesized using glycerin monostearate (GMS) and adipic acid dihydrazide (HZ) as lipid materials and named RGD-HZ-GMS. RGD-HZ-GMS was applied to encapsulate DOX to construct a RGD modified, DOX loaded SLNs (RGD-DOX-SLNs). To evaluate the anticancer effect of RGD-DOX-SLNs, breast cancer cell line (MCF-7 cells) and DOX resistant cell line (MCF-7/ADR cells) were used. in vivo tumor suspension and toxicity effects were evaluated on mice bearing MCF-7/ADR cells breast cancer model. RGD-DOX-SLNs had a uniformly spherical shape. The mean particle size and zeta potential of the RGD-DOX-SLNs was 96.3 nm and 35.6 mV, respectively. RGD-DOX-SLNs showed 5.58 fold higher area under the plasma concentration - time curve (AUC) compared with DOX solution. Terminal half life (T1/2) and peak concentration (Cmax) of RGD-DOX-SLNs was 10.85 h and 39.12 ± 2.71 L/kg/h. in vitro and in vivo antitumor results indicate that RGD-DOX-SLNs might be a promising novel lipid carrier which could improve breast cancer therapy.

Targeted delivery of ibrutinib to tumor-associated macrophages by sialic acid-stearic acid conjugate modified nanocomplexes for cancer immunotherapy.

Ibrutinib (IBR), an irreversible Bruton's tyrosine kinase (BTK) inhibitor, is expected to be a potent therapeutic modality, given that BTK is overexpressed in tumor-associated macrophages (TAMs) and participates in promoting tumor progression, angiogenesis, and immunosuppression. However, rapid clearance in vivo and low tumor accumulation have rendered effective uptake of IBR by TAMs challenge. Herein, we designed and synthesized a sialic acid (SA)-stearic acid conjugate modified on the surface of nanocomplexes to encapsulate IBR (SA/IBR/EPG) for targeted immunotherapy. Amphiphilic egg phosphatidylglycerol (EPG) structure and strong IBR-EPG interactions render these nanocomplexes high IBR loading capacity, prolonged blood circulation, and optimal particle sizes (∼30 nm), which can effectively deliver IBR to the tumor, followed by subsequent internalization of IBR by TAMs through SA-mediated active targeting. In vitro and in vivo tests showed that the prepared SA/IBR/EPG nanocomplexes could preferentially accumulate in TAMs and exert potent antitumor activity. Immunofluorescence staining analysis further confirmed that SA/IBR/EPG remarkably inhibited angiogenesis and tumorigenic cytokines released by TAM and eventually suppressed tumor progression, without eliciting any unwanted effect. Thus, SA-decorated IBR nanocomplexes present a promising strategy for cancer immunotherapy. STATEMENT OF SIGNIFICANCE: Ibrutinib (IBR), an irreversible Bruton's tyrosine kinase (BTK) inhibitor, is expected to be a potent therapeutic modality, given that BTK is overexpressed in tumor-associated macrophages (TAMs) and participates in promoting tumor progression, angiogenesis, and immunosuppression. However, rapid clearance in vivo and low tumor accumulation have rendered effective uptake of IBR by TAMs challenge. Herein, we designed and synthesized a sialic acid (SA)-stearic acid conjugate modified on the surface of nanocomplexes to encapsulate IBR (SA/IBR/EPG) for targeted delivery of IBR to TAMs. The developed SA/IBR/EPG nanocomplexes exhibited high efficiency in targeting TAMs and inhibiting BTK activation, consequently inhibiting Th2 tumorigenic cytokine release, reducing angiogenesis, and suppressing tumor growth. These results implied that the SA/IBR/EPG nanocomplex could be a promising strategy for TAM-targeting immunotherapy with minimal systemic side effects.

Mannose-functionalized solid lipid nanoparticles are effective in targeting alveolar macrophages.

Mannose receptor is highly expressed on alveolar macrophages, being a potential target to promote the specific local drug delivery of anti-tuberculosis agents through the use of functionalized nanocarriers. In this work, isoniazid (Isn)-loaded solid lipid nanoparticles (SLN), reinforced with stearylamine (SA) were produced by double emulsion technique and further surface-functionalized with mannose in a straightforward chemical approach. Upon pre-formulation assessment, SLN close to 500 nm average size, positively charged and with association efficiency of ISN close to 50% were obtained. Functionalization with mannose was performed after SLN production and confirmed by Fourier transform infrared spectroscopy (FTIR). Both functionalized and non-functionalized SLN demonstrated to devoid of toxicity when tested in human lung epithelial cell line (NCI-H441) and differentiated THP-1 (dTHP-1), reducing the intrinsic cytotoxicity of Isn when incorporated into SLN. Uptake studies were conducted on same macrophage-like cells and the results showed that fluorescent mannosylated SLN (M-SLN) were more efficient in be internalized comparatively to SLN. Moreover, the uptake of M-SLN was reduced when cells were pre-incubated with mannose, demonstrating the receptor-dependence internalization of functionalized SLN. These functionalized nanocarriers may represent a useful platform to target alveolar macrophages for delivering anti-infective drugs.

Preparation and characterization of adefovir dipivoxil-stearic acid cocrystal with enhanced physicochemical properties.

The objectives of this study were to prepare cocrystal composed of adefovir dipivoxil (AD) and stearic acid (SA) and to investigate the enhanced properties of the cocrystal. The cocrystal was prepared by antisolvent precipitation and characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRPD), and differential scanning calorimetry (DSC). The enhanced properties were evaluated by dissolution testing, permeability studies, and powder rheology analysis. The AD raw material has a cuboid-like crystal and the cocrystal has a needle shape. In the FT-IR study, there were bathochromic shifts caused by the hydrogen bonding. The melting point of the cocrystal was 52.9 °C, which was lower than that of AD. The XRPD pattern also had distinct differences, supporting the formation of a new crystalline form. The cocrystal showed changes in the lattice energy and the solvation strength, which caused an enhanced dissolution. The permeability was increased due to the SA, which acts as a P-gp inhibitor. The tabletability was enhanced due to the altered crystal habit. In conclusion, cocrystal containing AD and SA was successfully prepared, presenting advantages such as enhanced solubility, tabletability, and permeability. The use of the cocrystal is a desirable approach for the improved physicochemical properties.

Total synthesis and mass spectrometric analysis of a Mycobacterium tuberculosis phosphatidylglycerol featuring a two-step synthesis of (R)-tuberculostearic acid.

We report the total synthesis of (R)-tuberculostearic acid-containing Mycobacterium tuberculosis phosphatidylglycerol (PG). The approach features a two-step synthesis of (R)-tuberculostearic acid, involving an (S)-citronellyl bromide linchpin, and the phosphoramidite-assisted assembly of the full PG structure. Collision-induced dissociation mass spectrometry of two chemically-synthesized PG acyl regioisomers revealed diagnostic product ions formed by preferential loss of carboxylate at the secondary (sn-2) position.

Characterization of Synthesized and Commercial Forms of Magnesium Stearate Using Differential Scanning Calorimetry, Thermogravimetric Analysis, Powder X-Ray Diffraction, and Solid-State NMR Spectroscopy.

Magnesium stearate is the salt of a complex mixture of fatty acids, with the majority being stearate and palmitate. It has multiple crystalline forms and, potentially, an amorphous form. Magnesium stearate is used in the pharmaceutical manufacturing industry as a powder lubricant, and typically is added at low levels (∼1%) during the manufacturing process and blended for a relatively short time (∼5 min). Proper levels and mixing times are needed, as too short a mixing time or too small a quantity will result in improper lubrication, and too much can negatively impact dissolution rates. The complex mixture of multiple fatty acids and crystalline forms in magnesium stearate leads to variability between commercial sources, and switching between sources can impact both the amount of lubricant and mixing time needed for proper lubrication. In order to better understand the complex nature of magnesium stearate, a variety of analytical techniques were used to characterize both synthesized and commercial magnesium stearate samples. The results show that correlation among differential scanning calorimetry, thermogravimetric analysis, solid-state NMR spectroscopy, and other techniques provides a unique insight into the forms of magnesium stearate. Finally, the ability to monitor form changes of magnesium stearate in an intact tablet using solid-state NMR spectroscopy is shown.

Synthesis and Biological Evaluation of Chlorinated Analogs of Leukotoxin Diol.

This study documents that chlorinated analogs of leukotoxin diol 1, in which the vic-diol has been replaced with vic-chlorides (2), induce caspase 3 activity and apoptosis on HepG2 cells in a dose-dependent manner in analogy to the parent diol. This suggests that chlorides may substitute for hydroxyls in certain lipids as bioisosteres in defined biological settings.

Dry Powder Coating using Planetary Centrifugal Mixer.

PURPOSE: Extemporaneous compounding is an important part of pharmacy practice, and should be standardized and sophisticated to ensure the quality of the compounded preparations. Recently, we applied a planetary centrifugal mixer (PCM) to powder blending, which has attracted interest for its small scale and lack of contamination. In this study, we aimed to reveal the feasibility of dry powder coating through ordered mixing of fine particles using PCM. METHODS: Cohesive lactose powders (Pharmatose450M) were dry coated with magnesium stearate (MgSt) using from 0.1 to 5%(w/w) content. The operational variables tested were operation time (1-30 min), operation speed (400-1000 rpm), vessel size (24-100 mL), and charging rate in the vessel (20-40%). The processed powders were evaluated for their surface morphology, flowability, and wettability. Furthermore, fine ibuprofen particles were coated with various lubricants, and then the dissolution profiles were examined. The crystallinity of ibuprofen was assessed using FT-IR and PXRD. RESULTS: Lactose powders were successfully coated with MgSt using PCM. When the level of MgSt was over 1%, the surface of the lactose powders was thoroughly covered. Angles of repose were 51° and 41° for unprocessed and processed powders with 1% MgSt, respectively. The contact angle of the water drop on the 1% MgSt sample leached to be 132°, changing to a hydrophobic surface. Investigations under various operational conditions revealed that higher improvement was observed upon higher speed and longer time, and a smaller charging rate in the vessel. Vessel size had no impact. Moreover, improved dissolution of ibuprofen coated with both hydrophilic and hydrophobic lubricants was observed owing to good dispersing behavior. Besides, no alteration of crystallinity was detected. CONCLUSIONS: PCM is an effective tool for dry powder coating with low impact stress. The presented method will contribute a great deal to making crushed tablets a functional powder.

A scalable, nonenzymatic synthesis of highly stereopure difunctional C4 secondary methyl linchpin synthons.

In response to the continuing widespread use of heterodifunctional C4 secondary methyl building blocks in asymmetric synthesis, we have developed a mole-scale, two-step synthesis of a 1:1 mixture of the diastereomers of 3-bromo-2-methyl-1-propyl camphorsulfonate (casylate). One isomer (2S) has been crystallized to >99:1 dr in ∼25% yield. Equilibration of the mother liquor (enriched in 2R) to a 1:1 mixture and recrystallization significantly raises the overall yield of 2S. Applications of 2S include chemoselective Grignard coupling, enabling the very short synthesis of highly stereopure long-chain natural products containing remote, methyl-bearing stereogenic centers [e.g., (R)-tuberculostearic acid], with complete control of configuration. Also, Ag-mediated, completely chemoselective Br displacement from 2S leads to a range of >99:1 er difunctional synthons. Both applications incorporate concurrent recovery of CasO. The enantiomer of 2S can be made from commercial (1R)-10-CasOH.

Fluorine bonding enhances the energetics of protein-lipid binding in the gas phase.

This paper reports on the first experimental study of the energies of noncovalent fluorine bonding in a protein-ligand complex in the absence of solvent. Arrhenius parameters were measured for the dissociation of gaseous deprotonated ions of complexes of bovine ß-lactoglobulin (Lg), a model lipid-binding protein, and four fluorinated analogs of stearic acid (SA), which contained (X =) 13, 15, 17, or 21 fluorine atoms. In all cases, the activation energies (E(a)) measured for the loss of neutral XF-SA from the (Lg + XF-SA)7⁻ ions are larger than for SA. From the kinetic data, the average contribution of each > CF2 group to E(a) was found to be ~1.1 kcal mol⁻¹, which is larger than the ~0.8 kcal mol⁻¹ value reported for > CH2 groups. Based on these results, it is proposed that fluorocarbon­protein interactions are inherently stronger (enthalpically) than the corresponding hydrocarbon interactions.

Preparation and evaluation in vitro and in vivo of docetaxel loaded mixed micelles for oral administration.

A mixed micelle that comprised of monomethylol poly(ethylene glycol)-poly(D,L-lactic acid) (MPP), D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) and stearic acid grafted chitosan oligosaccharide(CSO-SA) copolymers was developed to enhance the oral absorption of docetaxel (DTX). DTX-loaded MPP/TPGS/CSO-SA mixed polymeric micelles (MPMs) were prepared with thin film hydration method and characterized in terms of morphology, size, zeta potential, encapsulation efficiency, critical micellization concentration, and in vitro stability in media modeling physiological conditions. The in vitro release of docetaxel from the mixed micelles was studied with dialysis method. The oral bioavailability studies were conducted in rats and the pharmacokinetic parameters were evaluated. The results showed that DTX-loaded MPP/TPGS/CSO-SA MPMs had a mean diameter of 34.96 nm and exhibited spherical shape under transmission electron microscopy. The drug loading of DTX in the mixed micelles was 19.15%. The critical micellization concentration of MPP/TPGS/CSO-SA copolymer was 2.11×10(-5) M, and the size of mixed micelles in gastric fluid (pH 1.6) for 2 h and simulated intestinal fluid (pH 6.5) for 6h showed no significant change. The in vitro release study showed that DTX-loaded MPP/TPGS/CSO-SA MPMs exhibited slower release characteristics compared to DTX solution. The oral bioavailability of the DTX-loaded MPP/TPGS/CSO-SA MPMs was increased by 2.52 times compared to that of DTX solution. The current results encourage further development of DTX mixed polymeric micelles as the oral drug delivery system.

Synthesis, antimicrobial evaluation and QSAR studies of stearic acid derivatives.

A series of Schiff bases (1-17) and esters (18-28) of stearic acid was synthesized and characterized by physicochemical as well as spectral means. The synthesized compounds were evaluated in vitro for their antimicrobial activity by tube dilution method. The antimicrobial screening results indicated that the compounds having electron releasing groups on benzylidene nucleus were found to be more active against bacterial strains and compounds having electron withdrawing groups on benzylidene nucleus were found to be more active against fungal strains. QSAR studies demonstrated that electronic parameters dipole moment (µ) and total energy (Te) were the most important descriptors in describing the antimicrobial activity of synthesized stearic acid derivatives.

Comparison of dipolar, H-bonding, and dispersive interactions on gelation efficiency of positional isomers of keto and hydroxy substituted octadecanoic acids.

A systematic study of the importance of functional group position and type on the gelator efficiencies of structurally simple, low molecular-mass gelators is reported. Thus, the gelation abilities of a series of positional isomers of ketooctadecanoic acid (n-KSA) are compared in a wide range of liquids. The gelation abilities of the n-KSA as a function of n, the keto group position along the chain, are characterized by several structural, thermal, and rheological techniques and are compared with those of the corresponding hydroxyoctadecanoic acid isomers (n-HSA) and the parent molecule, octadecanoic acid (SA). Analyses of the gels according to the strengths of functional group interactions along the alkyl chain in terms of group position and type are made. The conclusions derived from the study indicate that gel stability is enhanced when the functional group is located relatively far from the carboxylic headgroup and when group-group interactions are stronger (i.e., hydrogen-bonding interactions are stronger in the n-HSA than dipole interactions in the n-KSA, which are stronger than the London dispersion interactions in SA). Co-crystals of the keto- and hydroxy-substituted octadecanoic acids are found to be less efficient gelators than even the ketooctadecanoic acids, due to molecular packing and limited group interactions within the gelator networks.

Synthesis and characterization of some novel fatty acid analogues: a preliminary investigation on their activity against human lung carcinoma cell line.

BACKGROUND: Preparation of some novel heterocyclic compounds with long alkyl and alkenyl chain of cytotoxic activity. METHODS: Gamma linolenic acid, a poly unsaturated fatty acid and stearic acid, a saturated fatty acid were isolated from the microalga Spirulina platensis. Some novel gamma linolenic acid and stearic acid analogues having 1,3,4-oxadiazole and 1,2,4-triazole were synthesized and characterized by IR, 1H NMR, 13C NMR and mass spectral analysis. Cytotoxicity of these compounds was evaluated by the growth inhibition of A-549 cells in-vitro. RESULTS: Compound 1 and 3 showed comparable cytotoxicity against the human lung carcinoma A-549 cell lines.

Optimization of lipase-catalyzed synthesis of fructose stearate using response surface methodology.

In this study, immobilized lipase-catalyzed esterification reaction between fructose and stearic acid was examined for the synthesis of a useful compound, fructose stearate, using response surface methodology. The increase of water content in the reaction medium was the negative effect while the increase in initial stearic acid/fructose molar ratio was the greatest positive effect on the yield. The highest fructose stearate yield was obtained as 65% in tert-butanol. The product yield was enhanced in 1-butyl-3-methylimidazolium trifluoromethanesulfonate obtained as 74% under the optimized conditions. The spectroscopic and elemental analysis methods showed that the esterification reaction is regioselective and the product is fructose monostearate.

Effective antitumor gene therapy delivered by polyethylenimine-conjugated stearic acid-g-chitosan oligosaccharide micelles.

Non-viral vesicle composing of low-molecular weight polyethylenimine-conjugated stearic acid-g-chitosan oligosaccharide (CSOSA-g-PEI) was synthesized for gene delivery and therapy. The synthesized CSOSA-g-PEI had good ion-buffer capabilities and DNA-binding capacity, which could form positively charged nano-sized particles (100-150 nm) with plasmid DNA; in vitro gene transfection tests demonstrated that CSOSA-g-PEI presented much lower cytotoxicity and corresponding transfection efficiency in comparison with Lipofectamine 2000 in both human cancer cells (Hela and MCF-7). The gene transfection of CSOSA-g-PEI/pDNA could be further enhanced in the presence of serum or by adding arginine during incubation of CSOSA-g-PEI micelles with plasmid DNA. The biodistribution experiments demonstrated CSOSA-g-PEI conjugate highly localized in the tumor tissue and indicated a persistently increased accumulation. In vivo antitumor activity results showed that CSOSA-g-PEI/plasmid pigment epithelium-derived factor formulation could effectively suppress the tumor growth (above 60% tumor inhibition) without systematic toxicity against animal body after intravenous injection.