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Introduction. In the pharmaceutical technology field there is great interest in polymers with mucoadhesive properties, as they increase the drug retention time on the mucosal surface and increase the bioavailability of the drug. There are various mucoadhesive drug delivery systems: tablets, films, gels, suspensions of micro- and nanoparticles, etc. The ability to adhesion depends on the excipients, especially on their chemical structure. Molecular weight, surface charge, flexibility of the polymer chain and the presence of various functional groups play an important role. Polymers under the trade name Eudragit®, produced by the German concern Evonik Nutrition & Care GmbH, have been used in the pharmaceutical field for several decades to produce controlled-release oral dosage forms. Eudragit® EPO (EPO) is a ternary copolymer based on methacrylic acid derivatives and has mucoadhesive properties due to the presence of dimethylamino groups in its structure. The proposed chemical modification of Eudragit® EPO with a phenylboronic acid derivative, due to the presence of hydroxyl groups in their structure, leads to additional interaction with mucin oligosaccharides, providing enhanced mucoadhesive properties of this polymer.Aim. Synthesis and study of a chemically modified Eudragit® EPO using 4-bromophenylboronic acid in order to increase the mucoadhesive properties of the copolymer for use in transmucosal drug delivery systems.Materials and methods. The synthesis of chemically modified Eudragit® EPO (BEPO) was carried out for 24 hours at 50 °C, followed by purification by dialysis using a dialysis membrane (MMO = 12–14 kDa; Medicell International Ltd, UK) for 7 days and freeze drying at –50 °C and 0.05 mbar using Heto Power Dry LL 3000 (Thermo Electron Corporation, USA) for 5 days. Confirmation of the formation of ВЕРО was carried out by ATR-FTIR spectroscopy on a Nicolet iS5 spectrometer (Thеrmо Fisher Sciеntific, USA) and 1H-NMR spectroscopy on a DPX 400 MHz device (Bruker, Germany). Thermogravimetric analysis (TGA) and modulated differential scanning calorimetry (mDSC) were performed using Discovery TGA™ and Discovery DSC™ (TA Instruments, USA), respectively. The study of mucoadhesive properties was performed by the ability to retain the copolymer on the isolated sheep nasal mucosa at 37.0 ± 0.5 °C for 30 minutes.Results and discussion. BEPO was prepared with a substitution degree of dimethylamino groups with phenylboronic acid of 25 % (BEPO25) and 50 % (BEPO50). The yields of BEPO25 and BEPO50 were 40.70 and 30.79 %. The new characteristic band appears at 1605 cm–1 in the IR spectrum of BEPO, which indicates the attachment of phenylboronic acid to EPO. In the 1H-NMR spectrum of BEPO, the formation of additional peaks in the range of 7.8 and 7.5 ppm is observed, which are absent in the EPO spectrum, which indicates the presence of phenylboronic acid. According to TGA results the samples of boronated EPO have the thermal stability similar to the original EPO. The results of DSC analysis show that the glass transition temperature (Tg) of BEPO samples is somehow higher than the original EPO, which is probably associated with a decrease in the amount of free dimethylamino groups in the terpolymer structure. BEPO50 is retained on the surface of isolated sheep nasal mucosa for 30 minutes, while EPO is washed off with artificial nasal fluid in 5 minutes.Conclusion. The development and study of BEPO is a promising direction for further use in transmucosal drug delivery systems.

Solid dispersion formation by Hot melt extrusion (HME) is a widely used formulation strategy to improve the solubility and bioavailability of poorly water-soluble drugs. Despite this, they are limited by various factors such as drug-excipient miscibility, poor stability, limited drug loading and extrudability of physical drug-excipient mixtures. In this work, polyethylene glycol 8000 (PEG 8000) was used as a plasticizer for the manufacture of ellagic acid solid dispersions (EASD) with high drug loading. Indeed, EA is a polyphenolic active compound with antimalarial and other promising therapeutic activities. However, its low solubility and low permeability limit its therapeutic use. Solid dispersions formation may overcome this challenge, but its high melting point negatively influences the extrudability of its binary physical mixtures with a high drug loading rate, hence the need to use a plasticizer. Thus, five formulations consisting of EA, Eudragit® EPO and PEG 8000 in the ratio of 15:75:10 (F1), 20:70:10 (F2), 25:65:10 (F3), 15:80:5 (F4) and 20:85:5 (F5) % w/w, respectively, have been extruded, four of which were successful. The extrudates were evaluated by X-ray powder diffraction, FTIR spectroscopy and in vitro dissolution tests. Based on the results of these tests, the F5 formulation was identified as the most promising. Indeed, after 15 min of dissolution test, the dissolution rate of ellagic acid from the formulations was 62.67±3.10%, 58.74±7.23 %, 88.75±3.02% and 83.47±4.40% respectively for formulation F1, F2, F4 and F5. Moreover, the results of the FTIR spectroscopy analyses showed stronger interactions between the different constituents in the F4 and 5 formulations compared to the F1 and 2 formulations. Extruded materials of the F5 formulation, characterized by solid state nuclear magnetic resonance (ssNMR) spectroscopy and subjected to stability studies, showed good physical stability for twelve months under real-time stability study conditions and for six months under accelerated conditions.

Introduction : L’acide ellagique (AE) est un composé polyphénolique, possédant des propriétés antipaludiques ainsi que d’autres activités thérapeutiques prometteuses. Cependant, ses propriétés physicochimiques défavorables (faible solubilité et faible perméabilité, BCS IV) limitent sa biodisponibilité par voie orale. Le but de notre étude était de produire par extrusion à chaud des dispersions solides ternaires à taux de charge élevé en substance active en vue d’une utilisation efficiente de l’acide ellagique en thérapeutique humaine. Matériel et méthodes : Des mélanges physiques ternaires composés d’EA/Eudragit® EPO/PEG 8000 dans des proportions de 15/75/10 (F1), 20/70/10 (F2), 25/65/10 (F3), 15/80/5 (F4) et 20/85/5 (F5) % m/m, respectivement ont été triturés au mortier puis extrudés à l’aide d’une extrudeuse co- rotative bi- vis pour l’obtention des dispersions solides ternaires. Les extrudats broyés et tamisés ont été caractérisés par diffraction aux rayons X, spectroscopie infrarouge à transformée de fourrier, spectroscopie à résonnance magnétique nucléaire et par des tests de dissolution dans des conditions non sink en milieu acide (HCl 0,1N,). Résultats et Discussion : Quatre des cinq formulations ont été extrudés avec succès. Il s’agissait des formulations F1, F2, F4 et F5. La formulation F3 n’a pu être extrudée car nécessitait un couple moteur supérieur à la force maximale développée par l’extrudeuse (40Nm). La diffraction aux rayons X a montré la présence de résidus cristallins dans toutes les dispersions solides ternaires, confirmée par la spectroscopie à résonnance magnétique nucléaire. La libération de l’AE à partir des dispersions ternaires était beaucoup plus importante avec les formulations F4 et F5 comparativement aux formulations F1 et F2. En effet, après 15 min de test, les taux de dissolution de l’AE étaient 88,75±3,02%, 83,47±4,40%, 62,67±3,10 et 58,74±7,23 % respectivement pour les formulations F4, F5, F2 et F1. Le profil de libération de l’AE à partir des formulations F1 et F2 présentait une tendance à la recristallisation de ce dernier dans le milieu de dissolution. Conclusion : Au regard de ses performances pharmaceutiques, de sa teneur en AE et en plastifiant, la formulation F5 apparaissait comme étant la plus appropriée pour une utilisation efficiente de l’AE en thérapeutique humaine.

The aim of this study was the analysis of interpolyelectrolyte complexes (IPECs) based on Eudragit® EPO and Eudragit® L100 as prospective carriers for gastroretentive drug delivery systems (GRDDS) using two model drugs: metronidazole (MZ) and acyclovir (ACR). Eudragit® EPO/L100 IPECs with different pH concentrations were characterized by different degrees of swelling in mimicking fasted stomach medium (0.1 M HCl) and saved their shape for 6 h. The microenvironmental changes in IPEC structures in acidic medium were investigated using FT-IR spectroscopy, thermal and elemental analysis. IPEC samples showed bioadhesive properties that were not significantly different from the positive control (Carbopol) in the test with the mucin compacts. The release rate of metronidazole (class I BCS) from IPEC matrices increased with the increasing degree of swelling. IPEC 1 provided 49.62 ± 6.20% and IPEC 2 reached 87.69 ± 5.15% of metronidazole release after 6 h in mimicking fasted stomach medium (0.1 M HCl). The total amount of released acyclovir (class III BCS) from IPEC 1 was 25.76 ± 5.67% and from IPEC 2 was 21.48 ± 5.00%. Release of both drugs was controlled by relaxation of polymeric chains in matrices according to the Peppas–Sahlin model. According to the received results, investigated interpolymer complexes are prospects for further evaluation as carriers for gastroretentive bioadhesive systems.

Given that pectin is a well-known substance used for drug delivery, we aimed to obtain and further examine the efficacy of interpolyelectrolyte complexes based on citrus or apple pectin and the Eudragit ® EPO for using these carriers in oral drug delivery. To characterize the physicochemical properties of these compounds, turbidity, gravimetry, viscosity, elementary analysis, FTIR spectroscopy, and DSC analysis were utilized. Diffusion transport characteristics were evaluated to assess the swelling ability of the matrices and the release of diclofenac sodium. To examine the release parameters, mathematical modeling was performed by using the Korsmayer-Peppas and Logistic equations as well. During the turbidity study, stoichiometry compositions were selected for the developed IPECs EPO/PecA and EPO/PecC at pH values = 4.0, 5.0, 6.0, and 7.0. The FTIR spectra of the complexes were characterized by an increase in the intensity of the bands at 1610 cm -1 and 1400 cm -1 . According to the DSC analysis, IPEC has a certain Tg = 57.3 °C. The highest release rates were obtained for IPEC EPO/PecC_1 and EPO/PecC_4. The mechanism of drug transport from the matrices IPEC EPO/PecC, IPEC EPO/PecA_3, and EPO/PecA_4 can be characterized as Super Case II. Anomalous release (non-Fickian release) is typical for IPEC EPO/PecA_1 and EPO/PecA_2. Thus, the resulting systems can be further used for the effective delivery of the drugs to the colon.

Poor solubility is the major challenge involved in the formulation development of new chemical entities (NCEs), as more than 40% of NCEs are practically insoluble in water. Solid dispersion (SD) is a promising technology for improving dissolution and, thereby, the bioavailability of poorly soluble drugs. This study investigates the influence of a pH-sensitive acrylate polymer, EPO, on the physicochemical properties of rosuvastatin calcium, an antihyperlipidemic drug. In silico docking was conducted with numerous polymers to predict drug polymer miscibility. The screened-out polymer was used to fabricate the binary SD of RoC in variable ratios using the co-grinding and solvent evaporation methods. The prepared formulations were assessed for physiochemical parameters such as saturation solubility, drug content and in vitro drug release. The optimized formulations were further ruled out using solid-state characterization (FTIR, DSC, XRD and SEM) and in vitro cytotoxicity. The results revealed that all SDs profoundly increased solubility as well as drug release. However, the formulation RSE-2, with a remarkable 71.88-fold increase in solubility, presented 92% of drug release in the initial 5 min. The molecular interaction studied using FTIR, XRD, DSC and SEM analysis evidenced the improvement of in vitro dissolution. The enhancement in solubility of RoC may be important for the modulation of the dyslipidemia response. Therefore, pharmacodynamic activity was conducted for optimized formulations. Our findings suggested an ameliorative effect of RSE-2 in dyslipidemia and its associated complications. Moreover, RSE-2 exhibited nonexistence of cytotoxicity against human liver cell lines. Convincingly, this study demonstrates that SD of RoC can be successfully fabricated by EPO, and have all the characteristics that are favourable for superior dissolution and better therapeutic response to the drug.

Introduction. The possibility of obtaining IPC based on polyanions of various structures Eudragit®, Carbopol®, pectin, carrageenan and sodium alginate with oppositely charged polycations - Eudragit® EPO, Eudragit® RS/RL and chitosan, stabilized as already well-known by ionic bonds. It has been proven that interpolymer complexes with the participation of Eudragit® copolymers could be also formatted by hydrogen bonds too as well. Prepared polycomplexes are promising carriers for drug delivery systems (DDS) to various parts of the gastrointestinal tract (GIT): the mouth (orodispersible and buccal DDS), stomach (gastroretentive DDS) and intestine (colon-specific DDS). Aim. Study of interpolymer complexes based on a pair of Eudragit® EPO and Eudragit® S100 copolymers obtained in a medium of various organic solvents (ethyl alcohol and a mixture of isopropanol-acetone (in a ratio of 60:40, v/v) from the point of view of their use in oral matrix systems for the delivery of active pharmaceutical ingredients. Materials and methods. The synthesis of interpolymer complexes based on Eudragit® copolymers was carried out in organic solvents [ethyl alcohol or isopropanol-acetone mixture (in a ratio of 60:40, v/v)]. The structural features of the obtained IPCs were assessed by FTIR spectroscopy using a Nicolet iS5 instrument with a Smart iTR single ATR attachment (Thermo Scientific, USA) and differential scanning calorimetry with modulated temperature (mDSC) using a Discovery™ DSC instrument (TA Instruments, USA). The composition was determined using the method of elemental analysis on a Thermo Flash 2000 CHNS/O device (Thermo Fisher Scientific, UK). The swelling capacity of the obtained IPCs was evaluated in buffer media with pH values that mimic the pH of different parts of the gastrointestinal tract (GIT): 1.2; 5.8; 6.8 and 7.4. The release of theophylline (TEO) and diclofenac sodium (DS) was assessed on a ERWEKA DFZ II (ERWEKA GmbH, Germany) flow through cell apparatus in buffer media simulating the pH of various parts of the gastrointestinal tract for 7 hours. Results and discussion. All obtained IPCs are characterized by an excess of Eudragit® S100 in their composition. The obtained IPCs are stabilized by a cooperative system of ionic and hydrogen bonds. DSC thermograms of IPC samples are characterized by the presence of a single glass transition temperature, which confirms the absence of impurities of free copolymers in their composition, while with an increase in the content of Eudragit® S100 in the IPC composition, the glass transition temperature increases. The matrix based on IPC-1 disintegrated during the first 15 minutes of the experiment in a medium with pH 1.2, while matrices based on the rest of the IPC samples retain their shape for 7 hours and are characterized by pH-independent behavior. The release of TEO from polycomplex matrices is diffusion-controlled and occurs in accordance with Fick's law (IPC-2, IPC-4, and IPC-6) or can be characterized as «abnormal transport» (IPC-1, IPC-3 and IPC- 5), and also depends on the swelling capacity of the matrix. In contrast, the release of DS is dependent on surface erosion of the matrix, which is consistent with the Super Case II transport mechanism. Conclusion. The resulting interpolymer complexes Eudragit® EPO/Eudragit® S100 are promising carriers in matrix oral systems for the controlled delivery of active pharmaceutical ingredients, providing a prolonged release of BCS class I substances, depending on the diffusion rate from the swollen matrix, and a delayed release of BCS class II substances, controlled by surface processes erosion of the matrix.

This study investigated the effect of solid dispersions (SD) on solubility and release of Zafirlukast (ZA) by physical mixture (PM), solvent evaporation (SE) and kneading method (KM) with Eudragit EPO (EPO) as binary component and Poloxamer 188 (P188) and Poloxamer 407 (P407) as ternary components. The binary and ternary systems caused an increase of 322 folds and 356 folds in aqueous solubility of ZA, respectively. Formulations were characterized for solubility, FTIR, PXRD, DSC, SEM and dissolution studies. P407 was found to be an excellent solubility booster in combination with EPO. It was concluded that solubility and dissolution rate of ZA increased significantly when SD of the ZA was prepared by solvent evaporation method (1:7 ratio) using 15% P407 as ternary component. [ABSTRACT FROM AUTHOR]

The poor printability of most pharmaceutical polymers greatly restricts the application of the fused deposition modeling (FDM) technique in the field of personalized pharmaceutical preparations. General strategies to improve printability and provide practical guidelines for the optimization of formulations are lacking. Moreover, the mechanism associated with the smooth printing process of modified printing materials needs to be investigated. In this study, three different strategies were used to improve the FDM printability of typical brittle polymers with poor printability. The relationship among additives, material properties, and printability was explored. The finite element method was used to simulate the radial stress-strain behavior of the filament, while computational fluid dynamics was used to simulate the axial melt flow field in the printing head. It was found that the addition of an inert filler (i.e., talc), a drug with high melting points (i.e., diclofenac sodium), and a polymer with high strength (i.e., plasticized ethylcellulose) effectively improved the printability of plasticized Eudragit® EPO and Soluplus®. In addition, regulating the mechanical properties of filaments improved printability, and it was deduced that printable filaments should have neither very low stiffness nor very low flexibility. The suitable melt viscosity or shear-thinning property of the printing material facilitated smooth extrusion without filament breakage or nozzle blockage. The results of this study also showed that simulation could assist in understanding the stress-strain behavior of filaments and the flow field of melts during FDM printing., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Microencapsulation is one of the most commonly used taste masking techniques. It can be accomplished by various methods, including coacervation, solvent evaporation, extrusion and spray-drying. Enalapril maleate, a bitter-tasting ACE-inhibitor, is available worldwide in conventional tablet formulations and as oral solution in the USA. The purpose of this study was to develop enalapril-loaded microparticles using spray-drying and to test their taste masking potential. Eudragit EPO ® was used as a taste masking polymer for the preparation of a drugpolymer suspension. The suspension was then spray-dried under the following conditions: inlet temperature 65 °C, outlet temperature 30 °C, aspiration 100% and pump rate 10%. The drug-to-polymer ratio was varied and seven different microparticle models were developed. The yield of spray-dried particles ranged from of 51.3 to 85.4%, drug loading varied from 7.75 to 24.69% and encapsulation efficiency ranged from 58.5 to 95.7%. The particle size varied between 5.00 μm and 17.47 μm and the moisture content varied between 7.1% and 10.3%. In vitro taste assessment revealed minimal or no ENA release in artificial saliva. In vivo studies (with experimental animals and healthy volunteers) were used to evaluate the taste masking potential of spray-dried microparticles of enalapril maleate and Eudragit EPO ® .

الملخص: أهداف البحث: المضادات الحيوية هي الأدوية الأكثر شيوعا بين المرضى الأطفال. ومع ذلك، في معظم الأحيان، يصبح إعطاء الجرعة الدقيقة للأطفال مشكلة بسبب مذاقه المر للغاية. يعد سيفبودوكسيم بروكسيتيل وروكسيثروميسين أحد المضادات الحيوية التي توصف غالبا للأطفال ولها طعم مرير. التركيبات المسوقة لهذه الأدوية هي معلق جاف و/أو أقراص. من المعروف أن طريقة التجفيد تتضمن خطوات مختلفة وبالتالي فهي تستغرق وقتا طويلا ومكلفة. كان الهدف من هذه الدراسة هو إخفاء الطعم المر لسيفبودوكسيم بروكسيتيل وروكسيثروميسين دون المساس بالذوبان وشكل إطلاق الدواء عند مقارنته بالتركيبات المسوقة. بالإضافة إلى التغلب على العيوب المرتبطة بتقنية التجفيد المستخدمة حاليا. طريقة البحث: تم استخدام تقنية البثق بالذوبان الساخن لمعالجة سيفبودوكسيم بروكسيتيل وروكسيثروميسين بشكل فردي باستخدام بوليمر يودراجيت إيبو. تم تشخيص البثقات التي تم الحصول عليها بواسطة التحليل الطيفي للأشعة تحت الحمراء لتحويل فورييه، وقياس نمط الحيود للمواد البلورية وقياس السعرات الحرارية بالمسح التفاضلي. تمت صياغة البثقات المسحوقة كأقراص قابلة للتشتت وتم تقييمها من حيث كفاءة إخفاء الطعم داخل المختبر وفي الجسم الحي. النتائج: أظهرت الأقراص المحضرة في هذه الدراسة ملامح ذوبان قابلة للمقارنة ولكن تم تعزيز كفاءة إخفاء الطعم بشكل كبير عند مقارنتها بالأقراص المسوقة من سيفبودوكسيم بروكسيل وروكسيثروميسين. وكانت نتائج تقييم إخفاء الطعم البشري داخل الجسم متفقة أيضا مع دراسات إخفاء التذوق داخل المختبر. الاستنتاجات: وبالتالي فإن العمل الحالي قد قدم تكنولوجيا البثق بالذوبان الساخن الخالية من المذيبات والقابلة للتطوير والمستمرة لمعالجة مشكلات الطعم المر في سيفبودوكسيم بروكسيتيل وروكسيثروميسين. علاوة على ذلك، تم التغلب على العيوب المرتبطة بتقنية التجفيد المستخدمة حاليًا من خلال تطوير التركيبات باستخدام تقنية البثق بالذوبان الساخن. Abstract: Objectives: Antibiotics are the most commonly administered medications among pediatric patients. However most of the time, accurate dose administration to children becomes a problem due to the extremely bitter taste. Cefpodoxime proxetil (CP) and roxithromycin (ROX) are antibiotics often prescribed to the pediatric population and have a bitter taste. Marketed formulations of these drugs are dry suspension and/or tablets. The lyophilization method involves various steps and thus is time consuming and expensive. The objective of this study was to mask the bitter taste of CP and ROX without compromising the solubility and drug release profile compared to marketed formulations, as well as to overcome the disadvantages associated with the currently used lyophilization technique. Methods: Hot melt extrusion (HME) technology was used to process CP and ROX individually with Eudragit E PO polymer. The extrudates obtained were characterized by Fourier transform infrared spectroscopy, powder X-ray diffraction, and differential scanning calorimetry. The powdered extrudates were formulated as dispersible tablets and evaluated for in vitro and in vivo taste-masking efficiency. Results: The tablets prepared in this study showed comparable dissolution profiles but the taste-masking efficiency was significantly enhanced compared to the marketed tablets of CP and ROX. The results of in vivo human taste-masking evaluation were also in agreement with the in vitro taste-masking studies. Conclusion: The current work presents solvent-free, scalable, and continuous HME technology for addressing the bitter taste issues of CP and ROX. The disadvantages associated with the currently used lyophilization technique were overcome by developing the formulations using HME technology.

Curcumin and resveratrol are polyphenolic compounds that have been shown to exhibit synergistic therapeutic properties including anti-inflammatory, anticancer, and antiulcer activities, which may be exploited for the treatment of gastric diseases. However, both compounds have poor aqueous solubility and rapid metabolism, resulting in a low oral bioavailability. In situ gelling, liquid formulations were developed to produce a gastroretentive, raft-forming delivery vehicle to improve bioavailability. Solid dispersions containing a mixture of curcumin and resveratrol with Eudragit® EPO (Cur/Res-SD) were first prepared using solvent evaporation, to improve the solubility and dissolution of the compounds. Solid dispersions of a weight ratio of 1:10 curcumin/resveratrol to Eudragit® EPO were subsequently incorporated into in situ gelling, liquid formulations based on the gelling polymers, sodium alginate (low viscosity and medium viscosity), pectin, and gellan gum, respectively. Calcium carbonate and sodium bicarbonate were included to produce carbon dioxide bubbles in the gel matrix, on exposure to gastric fluid, and to achieve flotation. Moreover, the calcium ions acted as a crosslinking agent for the hydrogels. Optimized formulations floated rapidly (

Introduction. Orodispersible dosage forms are a very promising direction in the development of dosage forms. Such dosage forms are designed for both systemic and local action of the active pharmaceutical ingredients that make up their composition. Active pharmaceutical ingredients from orodispersible forms enter directly into the systemic circulation, bypassing the "first pass effect".Aim. Development of orodispersible tablets based on the Eudragit® EPO/ibuprofen polymer-drug complex and evaluation of ibuprofen release from the resulting system.Materials and methods. Samples of the polymer-drug complex (PDC) were obtained with different ratios of EPO and ibuprofen, as well as with different mixing orders. Turbidimetric studies to find the stoichiometry of the resulting EPO/IB PLC were performed spectrophotometrically (Lambda 25, PerkinElmer, U.S.A.) at a wavelength of 600 nm. Thermal analysis was performed by modulation differential scanning calorimetry (mDSC) on a Discovery™ DSC instrument (TA Instruments, U.S.A.). Samples sealed in Tzero aluminum pans (TA Instruments, U.S.A.) were scanned in the temperature range from 0 to 250 °С at a speed of 2 °С/min. IR spectra were recorded on a Nicolet iS5 FT-IR spectrometer (Thermo Fisher Scientific, U.S.A.) with an ATR nozzle, in the range from 500 to 4000 cm-1. Drying of samples of complexes and dispersible tablets was carried out in a FreeZone 1L laboratory freeze dryer (Labconco, U.S.A.) for a 24 hours at a temperature of –49 °C and at a pressure of 0.350 mbar. The drug release was evaluated on a dissolution tester DT 828 (ERWEKA GmbH, Germany) in a volume of 900 ml, at 37 ± 0.5 °C and a blade rotation speed of 50 rpm.Results and discussion. Studies on the formation of PDC Eudragit® EPO/ibuprofen (EPO/IB) were carried out at various molar ratios. On samples of PDC and individual components, bands are observed that are characteristic both for EPO – at 2770 and 2820 cm-1, confirming the presence of non-ionized dimethylamino groups, and at 1725 cm-1, corresponding to the stretching vibrations of carboxyl groups. A new band is appeared at 1573 cm-1, which confirm the formation of ionic bonds between carboxylate groups of IB and ionized dimethylamino groups of EPO. The mDSC thermograms of the samples are characterized by a single glass transition temperature (Tg) at 27,3 ± 0,3 °С (for molar ratio 1 : 2) and 44,9 ± 0,4 °С. (for molar ratio 1 : 1), which confirm the formation of polymer-drug complexes. Received PDC Eudragit® EPO/ibuprofen in a molar ratio of 1 : 2 and 1 : 1 and oral dispersible tablets based on them by lyophilization. The resulting systems are characterized by immediate release of IB with maximum rates at 30 min for a 1 : 1 composition and 60 min for a 1 : 2 composition.Conclusion. Eudragit® EPO/ibuprofen polymer drug complex can be used to develop orodispersible tablets providing immediate release of IB.

The purpose of this work was to evaluate the impact of polymer(s) on the dissolution rate, supersaturation and precipitation of indomethacin amorphous solid dispersions (ASD), and to understand the link between precipitate characteristics and redissolution kinetics. The crystalline and amorphous solubilities of indomethacin were determined in the absence and presence of hydroxypropylmethyl cellulose (HPMC) and/or Eudragit ® EPO to establish relevant phase boundaries. At acidic pH, HPMC could maintain supersaturation of the drug by effectively inhibiting solution crystallization while EPO increased both the crystalline and amorphous solubility of the drug, but did not inhibit crystallization. The HPMC dispersion dissolved relatively slowly without undergoing crystallization while the supersaturation generated by rapid dissolution of the EPO ASD was short-lived due to crystallization. The crystals thus generated underwent rapid redissolution upon pH increase, dissolving faster than the reference crystalline material, and at a comparable rate to the amorphous HPMC dispersion. A ternary dispersion containing both EPO and HPMC dissolved rapidly, generating an apparent drug concentration that exceeded the amorphous solubility of indomethacin, leading to the formation of a new nanosized droplet phase. These nanodroplets dissolved virtually immediately when the pH was increased. In conclusion, the concentration-time profiles achieved from indomethacin ASD dissolution are a complex interplay of drug release rate, precipitation kinetics and outcome, and precipitate redissolution rate, whereby each of these processes is highly dependent on the polymer(s) employed in the formulation. [ABSTRACT FROM AUTHOR]

Oily liquid drugs are not convenient for oral administration. We developed a powder containing clofibrate (CF), a model of an oily drug, using aminoalkyl methacrylate copolymer (EPO) or methacrylic acid copolymer (L100). CF or a mixture of CF and soybean oil was emulsified with EPO or L100 aqueous solution. Using a high-pressure homogenizer, a stable emulsion was obtained, and a powder was then obtained by lyophilization of the emulsion. The content of CF in the powder depended on the formulation, with the highest contents being 24.6% and 27.1% for EPO and L100, respectively. The incorporation ratio of CF was higher for L100 than for EPO. The powder using EPO was sticky because of leaked CF and the low glass transition temperature of EPO. The powder using L100 was a typical powder obtained by lyophilization. The leakage of CF from the powder was <2%, lower than for EPO powder. The dissolution of CF from powder using EPO was fast, regardless of the pH of the medium, but the powder using L100 showed enteric-soluble characteristics, indicating that CF is well incorporated in L100.

Flucloxacillin is prescribed to treat skin infections but its highly bitter taste is poorly tolerated in children. This work describes the application of the D-optimal mixture experimental design to identify the optimal component ratio of flucloxacillin, Eudragit EPO and palmitic acid to prepare flucloxacillin taste-masked microparticles that would be stable to storage and would inhibit flucloxacillin release in the oral cavity while facilitating the total release of the flucloxacillin load in the lower gastrointestinal tract (GIT). The model predicted ratio was found to be very close to the stoichiometric equimolar component ratio, which supported our hypothesis that the ionic interactions among flucloxacillin, Eudragit EPO and palmitic acid underscore the polyelectrolyte complex formation in the flucloxacillin taste-masked microparticles. The excipient–drug interactions showed protective effects on the microparticle storage stability and minimised flucloxacillin release at 2 min in dissolution medium. These interactions had less influence on flucloxacillin release in the dissolution medium at 60 min. Storage temperature and relative humidity significantly affected the chemical stability of the microparticles. At the preferred storage conditions of ambient temperature under reduced RH of 23%, over 90% of the baseline drug load was retained in the microparticles at 12 months of storage.