Biowaiver monographs for immediate release solid oral dosage forms: diclofenac sodium and diclofenac potassium

Development of Diclofenac Sodium 3D Printed Cylindrical and Tubular-Shaped Tablets through Hot Melt Extrusion and Fused Deposition Modelling Techniques

The present study aimed to develop 3D printed dosage forms, using custom-made filaments loaded with diclofenac sodium (DS). The printed tablets were developed by implementing a quality by design (QbD) approach. Filaments with adequate FDM 3D printing characteristics were produced via hot melt extrusion (HME). Their formulation included DS as active substance, polyvinyl alcohol (PVA) as a polymer, different types of plasticisers (mannitol, erythritol, isomalt, maltodextrin and PEG) and superdisintegrants (crospovidone and croscarmellose sodium). The physicochemical and mechanical properties of the extruded filaments were investigated through differential scanning calorimetry (DSC), X-ray diffraction (XRD) and tensile measurements. In addition, cylindrical-shaped and tubular-shaped 3D dosage forms were printed, and their dissolution behaviour was assessed via various drug release kinetic models. DSC and XRD results demonstrated the amorphous dispersion of DS into the polymeric filaments. Moreover, the 3D printed tablets, regardless of their composition, exhibited a DS release of nearly 90% after 45 min at pH 6.8, while their release behaviour was effectively described by the Korsmeyer-Peppas model. Notably, the novel tube design, which was anticipated to increase the drug release rate, proved the opposite based on the in vitro dissolution study results. Additionally, the use of crospovidone increased DS release rate, whereas croscarmellose sodium decreased it.

Synthesis, Characterization and Biocompatibility Evaluation of Novel Chitosan Lipid Micro-Systems for Modified Release of Diclofenac Sodium

The purpose of our study was the obtaining, characterization and biocompatibility estimation of novel carrier systems for diclofenac. Diclofenac is a potent nonsteroidal anti-inflammatory drug with frequent gastrointestinal side effects, impairing the quality of the patient's life. Original diclofenac-loaded micro-vesicles coated with chitosan were prepared and physico-chemical analyzed. We investigated their in vitro hemocompatibility and in vivo biocompatibility in rats. The animals were treated orally as follows: group 1 (Control): distilled water 0.3 mL/100 g body weight; Group 2 (CHIT): 0.3 mL/100 g body weight 0.5% chitosan solution; Group 3 (DCF): 15 mg/kg body weight diclofenac; Group 4 (DCF-ves): lipid vesicles loaded with diclofenac 15 mg/kg body weight. Blood samples were collected for assessing: red blood cells, hemoglobin, hematocrit and leukocyte formula. A series of specific parameters of the liver and kidney function, some markers of immune defense, as well as the activity of some enzymes involved in oxidative processes, were also investigated. At the end of the experiment, the animals were sacrificed and fragments of liver, kidney and stomach were collected for histopathological examination. No blood hemolysis was evidenced by the in vitro test with the administration of diclofenac vesicles. The animals treated with diclofenac lipid vesicles stabilized with chitosan did not display any notable differences in their hematological and biochemical profile compared to control animals. These data correlated with the histological results, which showed the absence of architectural changes in the examined tissues. Biological in vitro and in vivo evaluation revealed that the microvesicles containing diclofenac are biocompatible, with potential to be used as delivery systems to modify the drug release, thus making them an attractive candidate for biomedical applications.

Hybrid Polylactic-Acid-Pectin Aerogels: Synthesis, Structural Properties, and Drug Release

Wound-dressing materials often include other materials stimulating wound healing. This research describes the first formulation of biodegradable hybrid aerogels composed of polylactic acid and pectin. The prepared hybrid material showed a highly porous structure with a surface area of 166 ± 22.6 m²·g^-1. The addition of polylactic acid may have decreased the surface area of the pure pectin aerogel, but it improved the stability of the material in simulated body fluid (SBF). The pure pectin aerogel showed a high swelling and degradation ratio after 3 h. The addition of the polylactic acid prolonged its stability in the simulated body fluid from 24 h to more than one week, depending on the amount of polylactic acid. Biodegradable aerogels were loaded with indomethacin and diclofenac sodium as model drugs. The entrapment efficiencies were 63.4% and 62.6% for indomethacin and diclofenac sodium, respectively. Dissolution of both drugs was prolonged up to 2 days. Finally, sodium percarbonate and calcium peroxide were incorporated into the bioaerogels as chemical oxygen sources, to evaluate oxygen generation for potential wound healing applications.

Polyacrylamide/poly(2-(dimethylamino) Ethyl Methacrylate) Interpenetrating Polymer Networks as Drug Delivery Systems for Diclofenac Sodium

Nowadays, modern pharmaceutical investigations are directed toward the design and production of drug delivery systems for achieving prolonged and controlled drug delivery. In this respect, the use of interpenetrating polymer networks (IPNs) is an opportunity in the preparation of polymer drug delivery systems with desired characteristics. This paper describes the synthesis and characterization of novel poly(2-(dimethylamino) ethyl methacrylate) (PDMAEMA) and polyacrylamide (PAAm)-based IPNs with different compositions and their application as diclofenac sodium delivery systems. The prepared IPNs were shown to possess phase-separated structures at the nano level, as revealed by SEM and TM-DSC. The IPNs' composition was shown to determine the swelling behavior of these novel materials, and the inclusion of the charged IPN component (PDMAEMA) has changed the water molecules type diffusion from Fickian to non-Fickian, as revealed by the swelling kinetics study. Loading efficiency of diclofenac sodium and diclofenac sodium content in the polymer network was evaluated, and in vitro drug release experiments were carried out in order to estimate the ability of the obtained IPNs to control the release of the water-soluble drug.

Formulation and Evaluation of Diclofenac Potassium Gel in Sports Injuries with and without Phonophoresis

Background: Pain remains a global public heath priority. Phonophoresis, also known as sonophoresis or ultrasonophoresis, is when an ultrasound is used to maximize the effects of a topical drug. Purpose: The objective of this study was to test, in patients injured in sports or accidents (N = 200), the efficacy of diclofenac potassium (DK) 6%, 4%, and 2% formulated gels with and without phonophoresis in comparison with market available standard diclofenac sodium (DS or DN) gel. Methods: The patients were enrolled after informed consent. By using the lottery method, 100 patients were randomly segregated into five groups without phonophoresis and repeated similarly with phonophoresis at a frequency of 0.8 MHz, an intensity of about 1.5 W/cm2, and at continuous mode (2:1). Group-1 was treated with 6% DK gel, group-2 was treated with 4% DK gel, group-3 was treated with 2% DK gel, group-4 was treated with 4% DS gel and group-5 was given control gel three to four times a week for 4 weeks. The patients were screened by using NPRS and WOMAC scales. They were assessed on the baseline, 4th session, 8th session, 12th session, and 16th session. Results: Significant dose-dependently relief was observed in NPRS (Numeric Pain Rating Scale) and the WOMAC (Western Ontario McMaster Osteo-Arthritis) index for pain in disability and stiffness for each group treated with DK gel compared to DS gel. Phonophoresis increased these benefits significantly when used after topical application of DK gel or DS gel, and the dose-dependent effects of DK gel plus phonophoresis were stronger than the dose-dependent effects of DS gel plus phonophoresis. The faster and profounder relief was due to phonophoresis, which allows more penetration of the DK gel into the skin as compared to the direct application of DK gel in acute, uncomplicated soft tissue injury, such as plantar fasciitis, bursitis stress injuries, and tendinitis. In addition, DK gel with phonophoresis was well tolerated. Thus, in this personalized clinical setting, according to the degree of inflammation or injured-induced pain, disability, and stiffness, DK gel 6% with phonophoresis appeared more effective and thus more recommendable than DS gel 6% alone or DS gel 6% combined to phonophoresis.

Therapeutic Potential of a Water-Soluble Silver-Diclofenac Coordination Polymer on 3D Pancreatic Cancer Spheroids

This work describes the traditional wet and green synthetic approaches, structural features, and extensive bioactivity study for a new coordination polymer [Ag(μ-PTA)(Df)(H₂O)]_n·3nH₂O (1) that bears a silver(I) center, a 1,3,5-triaza-phosphaadamantane (PTA) linker, and a nonsteroidal anti-inflammatory drug, diclofenac (Df^-). Compared to cisplatin, compound 1 exhibits both anti-inflammatory properties and very remarkable cytotoxicity toward various cancer cell lines with a high value of selectivity index. Additionally, the 3D model representing human pancreas/duct carcinoma (PANC-1) and human lung adenocarcinoma (A549) was designed and applied as a clear proof of the remarkable therapeutic potential of 1. The obtained experimental data indicate that 1 induces an apoptotic pathway via reactive oxygen species generation, targeting mitochondria due to their membrane depolarization. This study broadens a group of bioactive metal-organic networks and highlights the significant potential of such compounds in developing advanced therapeutic solutions.

Modeling of In Vitro Dissolution Profiles of Carvedilol Immediate-Release Tablets in Different Dissolution Media

Quantitative evaluation of drug dissolution characteristics based on mathematical models is essential to understand and predict a particular drug release profile. In this study, model-dependent evaluation of the dissolution kinetics of reference and five test products (25-mg, immediate-release (IR) tablets) of an antihypertensive drug, carvedilol, was carried out using the DDSolver^® program. The effects of pH (pH 1.2, 4.5, and 6.8) and various media with/without 0.5% (w/v) anionic, cationic, and nonionic surfactants (sodium lauryl sulfate (SLS), hexadecyltrimethylammonium bromide (CTAB), and polysorbate 80) on the dissolution kinetics of the bioequivalent IR products of carvedilol were investigated. The Weibull-1 model was fitted successfully to the dissolution data of all products at pH 1.2 and pH 4.5, as well as in the pH 6.8 medium with CTAB according to the model goodness of fit (r² = 0.981-0.999, AIC = 14.5-42.6, MSC = 1.99-5.25). Model fitting produced good fits to Gompertz-1 for all products at pH 6.8 without a surfactant (r² = 0.975-0.998, AIC = 28.3-55, MSC = 2.53-5.82). For pH 6.8 media containing SLS or polysorbate 80, Logistic-2 was fitted successfully to the dissolution data of all products (r² = 0.974-0.999, AIC = 20.9-52.1, MSC = 1.90-5.69). Overall, the model-dependent analysis of in vitro dissolution data indicated in vitro equivalence of the reference and test products of carvedilol in each medium in terms of kinetic models, suggesting that it would have an important role in developing generic drug products of the BCS class II drug carvedilol.

New Non-Toxic N-alkyl Cholinium-Based Ionic Liquids as Excipients to Improve the Solubility of Poorly Water-Soluble Drugs

In this work, we prepared new biocompatible N-alkyl cholinium-based ionic liquids to be used as cosolvents to improve the solubility of poorly water-soluble drugs, namely, sodium diclofenac and paracetamol. In this set of ionic liquids, we intend to understand the effect of increasing the asymmetry of the ionic liquid cation/anion by growing the length of one of the alkyl chains attached to the nitrogen center/sulfonate center on the dissolution capacity of the ionic liquid. The addition of these new ionic liquids to water increased the dissolution capacity of the drugs up to four-times that in water, and improved the pharmacodynamic properties of these drugs, especially the case of sodium diclofenac. The intermolecular interactions between the drugs and ionic liquids were investigated by NMR. Two-dimensional 1H/1H nuclear overhauser effect spectroscopy (NOESY) revealed an interaction between sodium diclofenac and the alaninate anion from the [C2Ch]2[SucAla]. In the case of paracetamol and [C4Ch][C2SO3], it was possible to observe two intermolecular interactions between the hydroxyl group of paracetamol and two protons from the cation [C4Ch]+. Interestingly, the ionic liquid bearing a succinyl-DL-alaninate anion, [SucAla]2−, and a N-ethyl cholinium cation, [C2Ch]+, which presented the highest ability to dissolve sodium diclofenac, showed no cytotoxicity up to 500 mM. Therefore, this ionic liquid is a potential candidate for drug delivery applications.

On the usefulness of four in vitro methods in assessing the intraluminal performance of poorly soluble, ionisable compounds in the fasted state

A small-scale two-stage biphasic system, a small-scale two-stage dissolution-permeation system, the Erweka mini-paddle apparatus, and the BioGIT system were evaluated for their usefulness in assessing the intraluminal performance of two low solubility drugs in the fasted state, one with weakly acidic properties (tested in a salt form, diclofenac potassium) and one with weakly alkaline properties [ritonavir, tested as an amorphous solid dispersion (ASD) formulation].

In all in vitro methods, an immediate-release tablet and a powder formulation of diclofenac potassium were both rapidly dissolved in Level II biorelevant media simulating the conditions in the upper small intestine. Physiologically based biopharmaceutics (PBB) modelling for the tablet formulation resulted in a successful simulation of the average plasma profile in adults, whereas for the powder formulation modelling indicated that gastric emptying and transport through the intestinal epithelium limit the absorption rates.

Detailed information on the behaviour of the ritonavir ASD formulation under both simulated gastric and upper small intestinal conditions were crucial for understanding the luminal performance. PBB modelling showed that the dissolution and precipitation parameters, estimated from the Erweka mini-paddle apparatus data and the small-scale two-stage biphasic system data, respectively, were necessary to adequately simulate the average plasma profile after administration of the ritonavir ASD formulation. Simulation of the gastrointestinal transfer process from the stomach to the small intestine was necessary to evaluate the effects of hypochlorhydric conditions on the luminal performance of the ritonavir ASD formulation.

Based on this study, the selection of the appropriate in vitro method for evaluating the intraluminal performance of ionisable lipophilic drugs depends on the characteristics of the drug substance. The results suggest that for (salts of) acidic drugs (e.g., diclofenac potassium) it is only an issue of availability and ease of operation of the apparatus. For weakly alkaline substances (e.g., ritonavir), the results indicate that the dynamic dissolution process needs to be simulated, with the type of requested information (e.g., dissolution parameters, precipitation parameters, luminal concentrations) being key for selecting the most appropriate method. Regardless of the ionisation characteristics, early in the drug development process the use of small-scale systems may be inevitable, due to the limited quantities of drug substance available.

Modulation of biopharmaceutical properties of acidic drugs using cationic counterions: A critical analysis of FDA-approved pharmaceutical salts

Salification has a successful track record in modulating the biopharmaceutical properties of drugs. This is evident from the significant share (40%) of pharmaceutical salts in FDA-approved drugs in the past 80-years. Based on the ionic nature of drugs, the corresponding cationic or anionic counterions are employed for salification. This review aims to provide the contribution of cationic counterions in FDA-approved drugs from 1939 to 2020. The analysis of 80-years data has shown that the 7.1% of the FDA-approved drugs comprise cationic counterions (98 pharmaceutical salts). Heparin sodium is the pioneering drug in the history of pharmaceutical salts that was approved in 1939 as an anticoagulant medication. Inorganic (sodium, calcium, potassium, magnesium, silver), as well as organic (tromethamine, meglumine, erbumine) cationic counterions, were used in FDA-approved drugs with a major share by sodium (76 drugs). The technical superiority of cationic salts over other salt forms and the parent drug is also exemplified using case studies.

An Assessment of Occasional Bio-Inequivalence for BCS1 and BCS3 Drugs: What are the Underlying Reasons?

Despite having adequate solubility properties, bioequivalence (BE) studies performed on immediate release formulations containing BCS1/3 drugs occasionally fail. By systematically evaluating a set of 17 soluble drugs where unexpected BE failures have been reported and comparing to a set of 29 drugs where no such reports have been documented, a broad assessment of the risk factors leading to BE failure was performed. BE failures for BCS1/3 drugs were predominantly related to changes in C_max rather than AUC. C_max changes were typically modest, with minimal clinical significance for most drugs. Overall, drugs with a sharp plasma peak were identified as a key factor in BE failure risk. A new pharmacokinetic term (t½C_max) is proposed to identify drugs at higher risk due to their peak plasma profile shape. In addition, the analysis revealed that weak acids, and drugs with particularly high gastric solubility are potentially more vulnerable to BE failure, particularly when these features are combined with a sharp C_max peak. BCS3 drugs, which are often characterised as being more vulnerable to BE failure due to their potential for permeation and transit to be altered, particularly by excipient change, were not in general at greater risk of BE failures. These findings will help to inform how biowaivers may be optimally applied in the future.

Experimental investigation of ternary mixture of diclofenac sodium with pharmaceutical excipients

The goal of this work was the study of drug-excipient interactions of ternary mixtures between diclofenac sodium when introduced with excipients commonly explored in solid dosage formulas such as microcrystalline cellulose and stearic acid obtained by three methods. Differential scanning calorimetry (DSC) (DSC), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and the structural characterization technique of diffraction (XRPD) were used to investigate the characterization and potential physical and chemical interactions of solid products of diclofenac sodium with excipients prepared by different methods. This work revealed a possible interaction between diclofenac sodium, microcrystalline cellulose, and stearic acid in mixture prepared by microwave irradiation also; it was found compatibility for ternary mixtures prepared by physical mixture and co evaporation methods. Results of this study can be useful in the development of the method of preparation and select adequate excipients with suitable compatibility.

Development of a Biphasic-Release Multiple-Unit Pellet System with Diclofenac Sodium Using Novel Calcium Phosphate-Based Starter Pellets

Novel calcium phosphate-based starter pellets were used to develop a biphasic-release multiple-unit pellet system (MUPS) with diclofenac sodium as a model drug in the form of hard gelatin capsules. For comparative purposes, corresponding formulations based on the inert cores made of microcrystalline cellulose, sucrose and isomalt were prepared. The developed system consisted of two types of drug-layered pellets attaining different release patterns: delayed-release (enteric-coated) and extended-release. Dissolution characteristics were examined using both compendial and biorelevant methods, which reflected fed and fasting conditions. The results were collated with an equivalent commercial product but prepared with the direct pelletization technique.

Effect of gastrointestinal transit on micro-environmental pH inside HPMC matrix tablets - in vitro study

A commonly used approach to enhance the dissolution of drugs with pH-dependent solubility is the incorporation of pH modifiers. The aim of this study was to evaluate the duration and extent of pH modifying effect on the micro-environmental pH in HPMC matrix by applying two mechanistic approaches regarding hydrodynamic stress on the tested formulation (i.e. static dissolution apparatuses (USP2) and dynamic approaches including the Advanced gastric simulator (AGS) and the Intestinal model for simulation of peristaltic action (IMSPA)). Moreover, the aim of our research was also the preparation of sustained-release matrix systems with improved - enhanced drug dissolution. In our study, the occurrence of a pH gradient in the gel layer of the HPMC tablets was observed during simulation of their passage along different compartments of the GIT. The pH gradient was affected by the media composition and duration of tablet exposure to the surrounding media. Both dissolution methods were also used to evaluate the influence of the mechanical stress on the drug release kinetics. Micro-environmental pH (pH_M) was evaluated, using two methods: the cryostatic method with a surface pH electrode, and with the incorporation of a pH sensitive dye (methyl orange) into the matrix tablets. Our study demonstrates a significantly higher dissolution rate due to mechanical stress during the bio-relevant simulation of GIT transit of the mechanically sensitive HPMC tablets with poorly soluble drugs. A considerably higher release rate was also observed from tablets with the weakly basic drugs dipyridamole and propranolol hydrochloride containing pH modifier in case of mechanically bio-relevant dissolution models compared to the USP2 apparatus. For the assessment of the pH_M, the incorporation of a pH indicator dye in the HPMC tablet proved to be more suitable, while the cryostatic method was found to be useful only for a rough pH_M estimation.

Cashew Gum Polysaccharide Nanoparticles Grafted with Polypropylene Glycol as Carriers for Diclofenac Sodium

This investigation focuses on the development and optimization of cashew gum polysaccharide (CGP) nanoparticles grafted with polypropylene glycol (PPG) as carriers for diclofenac sodium. The optimization of parameters affecting nanoparticles formulation was performed using a central composite rotatable design (CCRD). It was demonstrated that the best formulation was achieved when 10 mg of CGP was mixed with 10 μL of PPG and homogenized at 22,000 rpm for 15 min. The physicochemical characterization evidenced that diclofenac was efficiently entrapped, as increases in the thermal stability of the drug were observed. The CGP-PPG@diclofenac nanoparticles showed a globular shape, with smooth surfaces, a hydrodynamic diameter around 275 nm, a polydispersity index (PDI) of 0.342, and a zeta potential of -5.98 mV. The kinetic studies evidenced that diclofenac release followed an anomalous transport mechanism, with a sustained release up to 68 h. These results indicated that CGP-PPG nanoparticles are an effective material for the loading/release of drugs with similar structures to diclofenac sodium.

Extemporaneous printing of diclofenac orodispersible films for pediatrics

OBJECTIVE

The possible application of a hot-melt ram extrusion printing to the preparation of diclofenac orodispersible films (ODF) made of maltodextrin was studied focusing the attention on the effects of taste-masking agents (i.e. namely mint, licorice-mint, and sucralose) and an opacifier (titanium dioxide [TiO₂]).

SIGNIFICANCE

This is a proof-of-concept of the feasibility to print ODF loaded with a thermosensitive drug substance by hot-melt technologies.

METHODS

Diclofenac sodium (DNa) ODF made of maltodextrin (dextrose equivalent (DE) = 6 ) plasticized with glycerol were prepared by hot-melt extrusion printing. ODF were characterized for disintegration time, drug content, and solid state, in vitro dissolution in deionized water and simulated salivary fluid at pH 5.7, tensile, and adhesive properties. Moreover, the stability of ODF was assessed in accelerated conditions over six months.

RESULTS

After the preparation, no variation in drug solid state was evident and the formation of impurity A of DNa was detected, even if it remained below the Pharmacopoeia (Ph. Eur.) limits (< 0.2%). Only the addition of DNa significantly improved the ODF tensile properties: the tensile strength increased from 0.17 ± 0.03 MPa (placebo ODF) to 2.21 ± 0.54 MPa (p ≤ 0.03). All ODF disintegrated in about 1 min, and the t_80% was lower than 3 min. TiO₂ reduced the static and dynamic peel forces (p ≤ 0.006) favoring the ODF detachment from the primary packaging material. During the accelerated stability study, ODF were easy to handle without fracture; the drug content, impurity A, and dissolution profiles remained superimposable.

CONCLUSION

Hot-melt printing can be suitable to prepare palatable ODF loaded with bitter thermosensitive drugs.

Composing Novel Diclofenac Potassium and l-Proline Salt Cocrystal as a Strategy to Increase Solubility and Dissolution

This research dealt with the multicomponent crystal developed from diclofenac potassium and l-proline to improve the pharmaceutical performance of this anti-inflammatory drug. Slow evaporation of the component mixture at a 1:1 M ratio, supported by ultrasonication, yielded a new salt cocrystal, which was characterized using thermal analysis, Karl Fischer titration, infrared spectrophotometry, powder diffractometry, and single crystal diffractometry. This salt cocrystal was confirmed as a tetrahydrate that comprised diclofenac potassium, l-proline, and water (1:1:4), named DKPH. The new salt cocrystal enhanced the solubility of diclofenac potassium by up to 3.56 folds and accelerated the intrinsic dissolution rate of 3.36 folds. It was supported by the solid and solution phase intermolecular interaction study. A different phase, which indicated a monohydrate form of the salt cocrystal, was found from the low humidity chamber during the isotherm sorption study. However, the tetrahydrate, DKPH, was proven as a stable form under ambient conditions.

Salt Cocrystal of Diclofenac Sodium-L-Proline: Structural, Pseudopolymorphism, and Pharmaceutics Performance Study

Previously, we have reported on a zwitterionic cocrystal of diclofenac acid and L-proline. However, the solubility of this multicomponent crystal was still lower than that of diclofenac sodium salt. Therefore, this study aimed to observe whether a multicomponent crystal could be produced from diclofenac sodium hydrate with the same coformer, L-proline, which was expected to improve the pharmaceutics performance. Methods involved screening, solid phase characterization, structure determination, stability, and in vitro pharmaceutical performance tests. First, a phase diagram screen was carried out to identify the molar ratio of the multicomponent crystal formation. Next, the single crystals were prepared by slow evaporation under two conditions, which yielded two forms: one was a rod-shape and the second was a flat-square form. The characterization by infrared spectroscopy, thermal analysis, and diffractometry confirmed the formation of the new phases. Finally, structural determination using single crystal X-ray diffraction analysis solved the new salt cocrystals as a stable diclofenac-sodium-proline-water (1:1:1:4) named NDPT (natrium diclofenac proline tetrahydrate), and unstable diclofenac-sodium-proline-water (1:1:1:1), named NDPM (natrium diclofenac proline monohydrate). The solubility and dissolution rate of these multicomponent crystals were superior to those of diclofenac sodium alone. The experimental results that this salt cocrystal is suitable for further development.

Hot melt extruded zein for controlled delivery of diclofenac sodium: Effect of drug loading and medium composition

This study evaluates the potential use of zein as an excipient in hot-melt extrusion for controlled delivery of diclofenac sodium (DS). Mixtures of zein, polyethylene glycol and drug were hot melt extruded and cut into 2 mm extrudates. Extrudates were characterised using differential scanning calorimetry, X-ray powder diffraction and scanning electron microscopy. The drug in the extrudates was found to be in the non-crystalline state, independent of the drug loading. Moreover, the drug release from extrudates was investigated. The release was directly dependent on the drug loading: a controlled and nearly zero-order release was obtained at the lowest drug loading (12.5% w/w), whereas almost immediate release was achieved at higher drug loadings, i.e. 25% and 37.5%. The release was inversely dependent on the ionic strength of the medium. The influence of digestive enzymes on drug release was also studied. Pancreatin, but not pepsin, was found to have a significant influence on the drug release as well as on the microstructure of zein extrudates. These data therefore support the potential use of zein as excipient in hot melt extrusion for controlled release purposes.

Synthesis and solid-state characterization of diclofenac imidazolium monohydrate: an imidazolium pharmaceutical ionic liquid

A new imidazolium hydrated salt (DCF–IMI–H₂O) of the nonsteroidal anti-inflammatory drug diclofenac (DCF) was synthesized by solvent evaporation.

Development of solid self-emulsifying drug delivery systems (SEDDS) to improve the solubility of resveratrol

Aim: A solid self-emulsifying drug delivery systems was developed by using the spray-drying technique, to improve the solubility of resveratrol (RES). Materials & methods: Cod liver oil and three surfactant system were tested: soy phosphatidylcholine (SPC)/Eumulgin® HRE-40 (EU)/Sodium oleate (system A); SPC/Tween®80 (TW) /Sodium oleate (system B) and SPC/EU/TW (system C). Results: The greatest incorporation was obtained with system C (21.26 mg/ml). Solid self-emulsifying drug delivery systems with the highest yield were obtained with colloidal silicon dioxide (CSD) (80.12%), and CSD sodium croscarmelose 9:1 and 5:5. RES dissolution attained 100% at 45 min with CSD:CS 5:5. Discussion: The surface modification to hydrophilic by CSD:sodium croscarmellose reduced the cohesive force among drug particles. Conclusion: The developed systems are a good approximation for the design of strategies that could allow increasing the oral bioavailability of RES.

Blend of cellulose ester and enteric polymers for delayed and enteric coating of core tablets of hydrophilic and hydrophobic drugs

The focus of this work was to explore feasibility of using blends of cellulose esters (CA 320S, CA 3980-10 or CAB 171-15) and enteric polymers (C-A-P, Eudragit® L100 or HPMCP HP-55) for delayed and enteric coating of tablets containing either diclofenac sodium (DFS, high dose) or prednisone (PDS, low dose) drug. The core tablets of DFS or PDS were coated with polymer blends to achieve approximate weight gain of 5% and 10%. The coated tablets were characterized for dissolution (0.1 N HCl and phosphate buffer pH 6.8) and surface morphology. The surface morphology of CA 398-10 or CAB 171-15 based polymer blends was rough and fibrous. Less than 0.5% drug was dissolved in 120 min from 5% w/w coated tablets in acid-phase dissolution testing. The dissolution in phosphate buffer pH 6.8 medium varied from 16.2 ± 0.2 to 98 ± 2.1%, and 30.1 ± 0.5% to 101.7 ± 3.4% in 120 min from DFS and PDS coated tablets, respectively. Dissolution was less in CA 320S based blends compared to CA 398-10 or CAB 171-15 blends in phosphate buffer medium. Furthermore, there were no significant differences observed in dissolution profiles of coated tablets of DFS or PDS. This can be explained by dose of the drugs. Additionally, dissolution was higher in tablets coated with enteric polymer alone compared with the blends. In conclusion, core tablets can be coated with cellulose ester and enteric polymers blend to impart both delayed and enteric release feature to the tablets containing hydrophilic or hydrophobic drug.

Safety and efficacy of curcumin versus diclofenac in knee osteoarthritis: a randomized open-label parallel-arm study

Background

The purpose of this study was to compare the efficacy and safety of curcumin with those of diclofenac in the treatment of knee osteoarthritis (OA).

Methods

In this randomized, open-label, parallel, active controlled clinical study, 139 patients with knee OA were randomly assigned to receive either a curcumin 500-mg (BCM-95^®) capsule three times daily or a diclofenac 50-mg tablet two times daily for 28 days. Patients underwent assessment at baseline and days 7, 14, and 28. The main outcome measure was severity of pain using visual analogue scale score at days 14 and 28. Knee Injury and Osteoarthritis Outcome Score (KOOS) (at days 14 and 28), anti-flatulent effect (at day 7), anti-ulcer effect, weight-lowering effect, and patient’s and physician’s global assessment of therapy at day 28 were included as secondary outcome measures. Safety after treatment was evaluated by recording adverse events and laboratory investigation.

Results

At days 14 and 28, patients receiving curcumin showed similar improvement in severity of pain and KOOS scale when compared with diclofenac, and the difference was not statistically significant. At day 7, the patients who received curcumin experienced a significantly greater reduction in the number of episodes of flatulence compared with diclofenac (P <0.01). At day 28, a weight-lowering effect (P <0.01) and anti-ulcer effect (P <0.01) of curcumin were observed. None of the patients required H2 blockers in the curcumin group, and 19 patients required H2 blockers in the diclofenac group (0% versus 28%, respectively; P <0.01). Adverse effects were significantly less in the curcumin group (13% versus 38% in the diclofenac group; P <0.01). Patient’s and physician’s global assessment of therapy was similar in the two treatment groups.

Conclusion

Curcumin has similar efficacy to diclofenac but demonstrated better tolerance among patients with knee OA. Curcumin can be an alternative treatment option in the patients with knee OA who are intolerant to the side effects of non-steroidal anti-inflammatory drugs.

Trial registration

ISRCTN, ISRCTN10074826. Registered 21 November 2017 - Retrospectively registered.

In vitro evaluation of the interchangeability of different brands of diclofenac sodium tablets available in the Colombian market

Introduction: Diclofenac sodium is classified as a non-steroidal anti-inflammatory drug. As diclofenac is an over-the-counter drug, its use among patients cannot be monitored by health teams in follow-up sessions. Given the multiple sources of diclofenac sodium, their interchangeability must be investigated, particularly in the form of in vitro studies, which are the most practical research type and entail minimal ethical commitment. Objectives: To determine the interchangeability of the different commercial brands of diclofenac sodium relative to the innovative product, this work carries out an in vitro study of eight commercial products of diclofenac sodium (50 mg) following the guidelines of the Biopharmaceutical Classification System. Materials and methods: Physical and chemical tests were developed following the guidelines of the 39th edition of the United States Pharmacopoeia. An analytical methodology was validated for the quantification of diclofenac according to the current pharmacopoeia and the Q2 guideline ofthe International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH). Dissolution profiles and their analyseswere governed by the regulations established by the World Health Organization and the national regulations. Results: All the products passed the physical tests. In the dissolution assays, the acid stage was overcome by all brands, but in the alkaline stage, one brand failed. The analysis of the similarities revealed that only one product was equivalent to the innovator and that three were supra-available, although these brands could also be considered equivalent to the innovator. Conclusions: Of the eight brands evaluated, three failed the test forthe active principle and the percentage of dissolution. Only one brand was found to be interchangeable with the innovator, and three were identified to besupra-availableand, thus, they do not present a risk for patients.

The Influence of Simulated Fasted Gastrointestinal pH Profiles on Diclofenac Sodium Dissolution in a Glass-Bead Flow-Through System

High inter- and intra-individual variability in the pH of fluids in the human gastrointestinal (GI) tract has been described in the literature. The aim of this study was to assess the influence of physiological variability in fasted pH profiles of media along the GI tract on diclofenac sodium (DF-Na) dissolution from matrix tablets. Four individual in vivo fasted pH profiles were selected from the literature that differed in pH values and transit times from the stomach to the proximal colon. Using a glass-bead device flow-through dissolution system, these pH profiles were simulated in vitro using a specific media sequence and considering simulated intestinal buffer capacities corresponding to in vivo literature data. Dissolution experiments were then performed in the same system with media sequence following individual pH profiles. In dissolution experiments, where influences of simulated gastric emptying time (GET), gastric pH value, small intestinal transit time, and colonic pH were studied; high influence of gastric pH value and GET on DF-Na dissolution was observed. The effect of variability in pH profiles in the range of individual in vivo data on DF-Na dissolution was also clearly observed in experiments, where dissolution studies were performed following three simulated in vivo individual pH profiles. The differences in DF-Na release between three individual pH profiles were substantial; they also reflected in simulated plasma concentration profiles and can be attributed to pH dependent diclofenac solubility.

Effect of Complexes and Microemulsions on the Permeability of Drugs: Determination Using a New Biomimetic Artificial Membrane

The aim of this work was to predict the permeability of two model drugs, sulfamerazine (SMR) and indomethacin (INM), and to determine the effect on their apparent permeabilities by complexation with cyclodextrins and/or meglumine or incorporation in microemulsions. Permeation experiments were performed using two-chamber diffusion cells with a new composition of bio-mimetic membrane composed of 80% of Lipoid® S100 and 20% of cholesterol in n-octanol 10% w/w solution, at 37 ± 0.5°C and 14,000 rpm. The predictive capacity of the permeability of passive diffusion absorbed compounds was evaluated using 20 drug standards and showed an exponential correlation between the apparent permeability coefficients (P_app) and the fraction absorbed percentages in humans (Fa%), with an R² value of 0.67942 and a constant value of - 4.1 ± 0.8. SMR and INM were classified as Class II and I, respectively, according to the Biopharmaceutical Classification System. These drugs were complexed and incorporated in microemulsions. The Fa% from all the drug products was higher than 90%. SMR in the complexes and both drugs in microemulsions were classified as highly soluble. Thus, SMR and INM incorporated in these pharmaceutical products could be classified as Class I.

In Vitro Evaluation of 2D-Printed Edible Films for the Buccal Delivery of Diclofenac Sodium

Printing technologies have recently emerged in the development of novel drug delivery systems toward personalized medicine, to improve the performance of formulations, existing bioavailability patterns, and patients' compliance. In the context of two-dimensional printing, this article presents the development of buccal films that are designed to efficiently deliver a class II compound (diclofenac sodium), according to the Biopharmaceutics Classification System (BCS), to the oral cavity. The preparation of drug-loaded inks was carried out based on solubility studies and evaluation of rheological properties, combining ethanol and propylene glycol as optimal solvents. Deposition of the drug was achieved by increasing the number of printing layers onto edible substrates, to produce formulations with dose variance. Thermal analysis, X-ray diffraction, and infrared spectroscopy were used to characterize the developed films. Drug loading and water uptake studies complemented the initial assessment of the films, and preliminary in vitro studies were conducted to further evaluate their performance. The in vitro release profiles were recorded in simulated saliva, presenting the complete release of the incorporated active in a period of 10 min. The effect of multiple layers on the overall performance of films was completed with in vitro permeation studies, revealing the correlation between the number of printed layers and the apparent permeability coefficient.

In Vitro-In Vivo Predictive Dissolution-Permeation-Absorption Dynamics of Highly Permeable Drug Extended-Release Tablets via Drug Dissolution/Absorption Simulating System and pH Alteration

Each of dissolution and permeation may be a rate-limiting factor in the absorption of oral drug delivery. But the current dissolution test rarely took into consideration of the permeation property. Drug dissolution/absorption simulating system (DDASS) valuably gave an insight into the combination of drug dissolution and permeation processes happening in human gastrointestinal tract. The simulated gastric/intestinal fluid of DDASS was improved in this study to realize the influence of dynamic pH change on the complete oral dosage form. To assess the effectiveness of DDASS, six high-permeability drugs were chosen as model drugs, including theophylline (pK_a1 = 3.50, pK_a2 = 8.60), diclofenac (pK_a = 4.15), isosorbide 5-mononitrate (pK_a = 7.00), sinomenine (pK_a = 7.98), alfuzosin (pK_a = 8.13), and metoprolol (pK_a = 9.70). A general elution and permeation relationship of their commercially available extended-release tablets was assessed as well as the relationship between the cumulative permeation and the apparent permeability. The correlations between DDASS elution and USP apparatus 2 (USP2) dissolution and also between DDASS permeation and beagle dog absorption were developed to estimate the predictability of DDASS. As a result, the common elution-dissolution relationship was established regardless of some variance in the characteristic behavior between DDASS and USP2 for drugs dependent on the pH for dissolution. Level A in vitro-in vivo correlation between DDASS permeation and dog absorption was developed for drugs with different pKa. The improved DDASS will be a promising tool to provide a screening method on the predictive dissolution-permeation-absorption dynamics of solid drug dosage forms in the early-phase formulation development.

Biopharmaceutical evaluation of surface active ophthalmic excipients using in vitro and ex vivo corneal models

The objective of this study was to systematically investigate the effects of surface active ophthalmic excipients on the corneal permeation of ophthalmic drugs using in vitro (HCE-T cell-based model) and ex vivo (freshly excised porcine cornea) models. The permeation of four ophthalmic drugs (i.e., timolol maleate, chloramphenicol, diclofenac sodium and dexamethasone) across in vitro and ex vivo corneal models was evaluated in the absence and presence of four commonly used surface active ophthalmic excipients (i.e., Polysorbate 80, Tyloxapol, Cremophor® EL and Pluronic® F68). The concentration and self-aggregation-dependent effects of surface active ophthalmic excipients on ophthalmic drug permeability were studied from the concentration region where only dissolved monomer molecules of surface active ophthalmic excipients exist, as well as the concentration region in which aggregates of variable size and dispersion are spontaneously formed. Neither the surface active ophthalmic excipients nor the ophthalmic drugs at all concentrations that were tested significantly affected the barrier properties of both corneal models, as assessed by transepithelial electrical resistance (TEER) monitoring during the permeability experiments. The lowest concentration of all investigated surface active ophthalmic excipients did not significantly affect the ophthalmic drug permeability across both of the corneal models that were used. For three ophthalmic drugs (i.e., chloramphenicol, diclofenac sodium and dexamethasone), depressed in vitro and ex vivo permeability were observed in the concentration range of either Polysorbate 80, Tyloxapol, Cremophor® EL or Pluronic® F68, at which self-aggregation is detected. The effect was the most pronounced for Cremophor® EL (1 and 2%, w/V) and was the least pronounced for Pluronic® F68 (1%, w/V). However, all surface active ophthalmic excipients over the entire concentration range that was tested did not significantly affect the in vitro and ex vivo permeability of timolol maleate, which is the most hydrophilic ophthalmic drug that was investigated. The results of the dynamic light scattering measurements point to the association of ophthalmic drugs with self-aggregates of surface active ophthalmic excipients as the potential mechanism of the observed permeability-depressing effect of surface active ophthalmic excipients. A strong and statistically significant correlation was observed between in vitro and ex vivo permeability of ophthalmic drugs in the presence of surface active ophthalmic excipients, which indicates that the observed permeability-altering effects of surface active ophthalmic excipients were comparable and were mediated by the same mechanism in both corneal models.

Evaluating bioequivalence of meloxicam tablets: is in-vitro dissolution test overdiscriminating?

OBJECTIVES

The aim of the study was to assess the impact of the differences in dissolution profiles of meloxicam tablets on the in-vivo bioavailability parameters after oral administration.

METHODS

Compare in-vitro dissolution testing in the recommended media to evaluate in-vivo bioequivalence outcomes for the Biopharmaceutics Classification System Class II weak acidic drugs. Nine Beagle dogs received a single oral administration of each formulation (7.5 mg) in a three-way crossover design.

KEY FINDINGS

The dissolution of meloxicam from both test products showed marked differences with that from the reference tablet in pH 1.0, 4.5 and 6.8 media at 50 or 75 rpm. Both formulations exhibiting slow or fast dissolution were then compared with the reference product for in-vivo bioequivalence study. Both products were bioequivalent with the reference tablet in either extent or rate of oral absorption. It indicated that the dissolution profiles which discriminated between the formulations in vitro did not accurately predict the in-vivo bioequivalence outcomes.

CONCLUSIONS

Comparative dissolution profiles using similarity factor (f₂ ) in the recommended media should be relaxed to fulfil the requirements for the development, scale-up and postapproval changes to immediate release oral solid dosage forms of meloxicam.

Assessing the risk of alcohol-induced dose dumping from sustained-release oral dosage forms: in vitro-in silico approach

Consumption of alcoholic beverages with sustained-release oral dosage forms may pose a risk to patients due to potential alcohol-induced dose dumping (ADD). Regulatory guidances recommend in vitro dissolution testing to identify the risk of ADD, but the question remains whether currently proposed test conditions can be considered biopredictive. The purpose of this study was to evaluate different dissolution setups to assess ADD, and the potential of combined in vitro-in silico approach to predict drug absorption after concomitant alcohol intake for hydrophilic and lipophilic sustained-release tablets containing ibuprofen or diclofenac sodium. According to the obtained results, the impact of ethanol was predominantly governed by the influence on matrix integrity, with the increase in drug solubility being less significant. Hydrophilic matrix tablets were less susceptible to ADD than lipophilic matrices, although the conclusion on formulation ethanol-vulnerability depended on the employed experimental conditions. In silico predictions indicated that the observed changes in drug dissolution would not result in plasma concentrations beyond therapeutic window, but sustained-release characteristics of the formulations might be lost. Overall, the study demonstrated that in vitro-in silico approach may provide insight into the effect of ADD on drug clinical performance, and serve as a tool for ADD risk assessment.

Effect of terpenes on transdermal iontophoretic delivery of diclofenac potassium under constant voltage

OBJECTIVE

The aim of the study was to enhance the transdermal delivery of diclofenac potassium (DP) from hydrogels by constant voltage iontophoresis (CVI). The other objective was to establish the safety and efficacy of CVI in rats.

MATERIALS AND METHODS

Hydrogels of DP were developed using hydroxyethyl cellulose as matrix material and geraniol, l-menthol and thymol as iontophoretic efficiency enhancers (IEE). In vitro permeation of hydrogels under CVI (1.5 V) was performed in Franz diffusion cells across porcine skin. The ability of CVI to deliver therapeutic amount of DP in vivo was assessed in rat paw edema model.

RESULTS

CVI significantly (p < 0.05) increased the steady state flux of DP compared to the passive. The hydrogels containing geraniol and l-menthol enhanced the iontophoretic flux of DP by ∼4.75 and ∼4.49 fold, respectively compared to passive control. The in vivo studies indicated that CVI in combination with IEE, significantly reduced (p < 0.05) area under the curve (AUC) of % inflammation compared to passive treatment. An excellent correlation (r = 0.996) was noted between in vitro flux values and AUC of % inflammation.

CONCLUSION

The preclinical studies conclusively demonstrated that CVI in combination with IEE's such as geraniol or l-menthol has the potential to safely deliver therapeutic amounts of DP.

Modeling and comparison of release profiles: Effect of the dissolution method

During the last decades, the study of the in vitro dissolution of pharmaceuticals has been strongly encouraged by the FDA in order to determine its relationship with the in vivo bioavailability of a drug. In this work immediate and extended release formulations containing diclofenac, a BCS class II drug, were studied using different dissolution methods. The release profiles obtained in USP Apparatus II and USP Apparatus IV were evaluated and compared to determine the effect of the fluid dynamic conditions on the release. The influence of the mixing conditions (i.e. the paddle rotation speed in USP Apparatus II or the inlet flow rate in USP Apparatus IV) on the drug release were evaluated, finding that, for the extended release formulations, they do not affect significantly the release profile. An in vitro device simulating the peristaltic contractions of the stomach during the digestion was used to simulate fluid dynamics closer to the real physiology. The tablets were found to behave in a completely different way if tested in the artificial stomach. Both model-independent and model-dependent approaches were used to compare and fit the dissolution profiles, respectively. Fit factors were used as indicators of similarity of two dissolution profiles; model equations (such as zero-order, first-order, or Korsmeyer-Peppas equations) were used to fit the experimental data. With the identification of the best fitting model by the use of correlation factors and Akaike Information Criterion, the transport phenomena that determine the behavior of each formulation were identified.

Quality by Design Empowered Development and Optimisation of Time-Controlled Pulsatile Release Platform Formulation Employing Compression Coating Technology

The research was envisaged for development of time-controlled pulsatile release (PR) platform formulation to facilitate management of early morning chronological attacks. The development was started using prednisone as a model drug wherein core tablets were prepared using direct compression method and subsequently compression-coated with ethylcellulose (EC)-hydroxypropyl methylcellulose (HPMC) excipient blend. Initially, quality target product profile was established and risk assessment was performed using failure mode and effect analysis. In an endeavour to accomplish the objective, central composite design was employed as a design of experiment (DoE) tool. Optimised compression-coated tablet (CCT) exhibited 4-6 h lag time followed by burst release profile under variegated dissolution conditions viz. multi-media, change in apparatus/agitation and biorelevant media. Afterwards, five different drugs, i.e. methylprednisolone, diclofenac sodium, diltiazem hydrochloride, nifedipine and lornoxicam, were one-by-one incorporated into the optimised prednisone formula with replacement of former drug. Change in drug precipitated the issues like poor solubility and flow property which were respectively resolved through formulation of solid dispersion and preparation of active pharmaceutical ingredient (API) granules. Albeit, all drug CCTs exhibited desired release profile similar to prednisone CCTs. In nutshell, tour de force of research epitomised the objective of incorporating diverse drug molecules and penultimately obtaining robust release profile at varying dissolution conditions.

In Situ Hydrogel Formulation for Intra-Articular Application of Diclofenac Sodium-Loaded Polymeric Nanoparticles

Objectives

The world's population is getting older and the number of people suffering from arthritis is a major problem according to World Health Organization's data. In this respect, the need for more efficient treatment for arthritis becomes an urgent issue. In this research, nanoparticle bearing in situ gelling hydrogel formulation was developed for prolonged local delivery of diclofenac sodium (DS).

Materials and Methods

Emulsion-solvent evaporation technique was used for the preparation of nanoparticles. Particle size, encapsulation efficiency, morphology, and drug release profile of DS loaded biodegradable nanoparticles as well as gel viscosity and gelation time of in situ gelling hydrogel formulations were optimized to increase the time interval between each dose application for enhanced patience compliance.

Results

The spherical nanoparticles with a mean particle diameter of 168 nm was obtained and confirmed by both transmission electron microscope and atomic force microscope. Different types of surfactants were tested in the first emulsification step of nanoparticle production process and Arlacel^®-C significantly increased the encapsulation efficiency to 89.7%. Thirty days prolonged in vitro release of DS was achieved by using the combined formulation of polymeric nanoparticles and in situ hydrogel prepared by using poloxomer 407 and chitosan.

Conclusion

Local administration of DS with this novel delivery system could be considered of having potential to minimize side effects associated with decreased amount of drug in dosage form compared to conventional oral dose.

Development and Validation of an Ultra Performance Liquid Chromatography Method for the Determination of Dexketoprofen Trometamol, Salicylic Acid and Diclofenac Sodium

OBJECTIVES

A simple, fast, accurate and precise method has been developed for the determination of dexketoprofen trometamol (DKP), salicylic acid (SA) and diclofenac sodium (DIC) in the drug solutions using ultra high performance liquid chromatography (UPLC).

MATERIALS AND METHODS

UPLC method is highly reliable and sensitive method to quantify the amount of the active ingredient and the method is validated according to ICH guidelines.

RESULTS

The developed method is found to be precise, accurate, specific and selective. The method was also found to be linear and reproducible. The value of limit of dedection (LOD) of DKP, SA, DIC were found 0.00325 µg/mL, 0.0027 µg/mL and 0.0304 µg/mL, respectively. The limit of quantitation (LOQ) of DKP, SA and DIC were found 0.00985 µg/mL, 0.0081 µg/mL and 0.0920 µg/mL, respectively.

CONCLUSION

Proposed methods can be successfully applicable to the pharmaceutical preparation containing the above mentioned drugs (dexketoprofen trometamol, salicylic acid and diclofenac sodium). Even very small amounts of active substance can be analyzed and validations can be performed easily.