Alternatives to Conventional Topical Dosage Forms for Targeted Skin Penetration of Diclofenac Sodium.

Skin penetration of an active pharmaceutical ingredient is key to developing topical drugs. This penetration can be adjusted for greater efficacy and/or safety through the selection of dosage form. Two emerging dosage forms, cream-gel and gel-in-oil emulsion, were tested for their ability to deliver diclofenac into the skin, with the target of maximising skin retention while limiting systemic exposure. Prototypes with varying amounts of solvents and emollients were formulated and evaluated by in vitro penetration testing on human skin. Cream-gel formulas showed better skin penetration than the emulgel benchmark drug even without added solvent, while gel-in-oil emulsions resulted in reduced diffusion of the active into the receptor fluid. Adding propylene glycol and diethylene glycol monoethyl ether as penetration enhancers resulted in different diclofenac penetration profiles depending on the dosage form and whether they were added to the disperse or continuous phase. Rheological characterisation of the prototypes revealed similar profiles of cream-gel and emulgel benchmark, whereas gel-in-oil emulsion demonstrated flow characteristics suitable for massaging product into the skin. This study underlined the potential of cream-gel and gel-in-oil emulsions for adjusting active penetration into the skin, broadening the range of choices available to topical formulation scientists.

Novel nano-in-micro fabrication technique of diclofenac nanoparticles loaded microneedle patches for localised and systemic drug delivery.

Diclofenac, a nonsteroidal anti-inflammatory drug, is commonly prescribed for managing osteoarthritis, rheumatoid arthritis, and post-surgical pain. However, oral administration of diclofenac often leads to adverse effects. This study introduces an innovative nano-in-micro approach to create diclofenac nanoparticle-loaded microneedle patches aimed at localised, sustained pain relief, circumventing the drawbacks of oral delivery. The nanoparticles were produced via wet-milling, achieving an average size of 200 nm, and then incorporated into microneedle patches. These patches showed improved skin penetration in ex vivo tests using Franz-cell setups compared to traditional diclofenac formulations. In vivo tests on rats revealed that the nanoparticle-loaded microneedle patches allowed for quick drug uptake and prolonged release, maintaining drug levels in tissues for up to 72 h. With a systemic bioavailability of 57 %, these patches prove to be an effective means of transdermal drug delivery. This study highlights the potential of this novel microneedle delivery system in enhancing the treatment of chronic pain with reduced systemic side effects.

Forecasting the effect of water gastric emptying patterns on model drug release in an in vitro glass-bead flow-through system.

Oral solid dosage forms are most frequently administered with a glass of water which empties from the stomach relatively fast, but with a certain variability in its emptying kinetics. The purpose of this study was thus to simulate different individual water gastric emptying (GE) patterns in an in vitro glass-bead flow-through dissolution system. Further, the effect of GE on the dissolution of model drugs from immediate-release tablets was assessed by determining the amount of dissolved drug in the samples pumped out of the stomach compartment. Additionally, different HCl solutions were used as dissolution media to assess the effect of the variability of pH of the gastric fluid on the dissolution of three model drugs: paracetamol, diclofenac sodium, and dipyridamole. The difference in fast and slow GE kinetics resulted in different dissolution profiles of paracetamol in all studied media. For diclofenac sodium and dipyridamole tablets, the effect of GE kinetics was well observed only in media, where the solubility was not a limiting factor. Therefore, GE kinetics of co-ingested water influences the drug release from immediate-release tablets, however, in certain cases, other parameters influencing drug dissolution can partly or fully hinder the expression of this effect.

UiO-66(Zr) as drug delivery system for non-steroidal anti-inflammatory drugs.

The toxicity for the human body of non-steroidal anti-inflammatory drugs (NSAIDs) overdoses is a consequence of their low water solubility, high doses, and facile accessibility to the population. New drug delivery systems (DDS) are necessary to overcome the bioavailability and toxicity related to NSAIDs. In this context, UiO-66(Zr) metal-organic framework (MOF) shows high porosity, stability, and load capacity, thus being a promising DDS. However, the adsorption and release capability for different NSAIDs is scarcely described. In this work, the biocompatible UiO-66(Zr) MOF was used to study the adsorption and release conditions of ibuprofen, naproxen, and diclofenac using a theoretical and experimental approximation. DFT results showed that the MOF-drug interaction was due to an intermolecular hydrogen bond between protons of the groups in the defect sites, (µ3 - OH, and - OH2) and a lone pair of oxygen carboxyl functional group of the NSAIDs. Also, the experimental results suggest that the solvent where the drug is dissolved affects the adsorption process. The adsorption kinetics are similar between the drugs, but the maximum load capacity differs for each drug. The release kinetics assay showed a solvent dependence kinetics whose maximum liberation capacity is affected by the interaction between the drug and the material. Finally, the biological assays show that none of the systems studied are cytotoxic for HMVEC. Additionally, the wound healing assay suggests that the UiO-66(Zr) material has potential application on the wound healing process. However, further studies should be done.

Effect of cytochrome P450 inhibition on toxicity of diclofenac in chickens: Unravelling toxicity in Gyps vultures.

Diclofenac was responsible for the decimation of Gyps vulture species on the Indian subcontinent during the 1980s and 1990s. Gyps vultures are extremely sensitive (the lethal dose 50 [LD50] ~ 0.1 mg/kg - 0.2 mg/kg), with toxicity appearing to be linked to metabolic deficiency, demonstrated by the long T1/2 (~12 h - 17 h). This is in striking comparison to the domestic chicken (Gallus gallus domesticus), in which the LD50 is ~10 mg/kg and the T1/2 is ~1 h. The phase 1 cytochrome P450 (CYP) 2C subfamily has been cited as a possible reason for metabolic deficiency. The aim of this study was to determine if CYP2C9 homolog pharmacogenomic differences amongst avian species is driving diclofenac toxicity in Gyps vultures. We exposed each of 10 CYP-inhibited test group chickens to a unique dose of diclofenac (as per the Organisation for Economic Co-operation and Development [OECD] toxicity testing guidelines) and compared the toxicity and pharmacokinetic results to control group birds that received no CYP inhibitor. Although no differences were noted in the LD50 values for each group (11.92 mg/kg in the CYP-inhibited test group and 11.58 mg/kg in the control group), the pharmacokinetic profile of the test group was suggestive of partial inhibition of CYP metabolism. Evaluation of the metabolite peaks produced also suggested partial metabolic inhibition in test group birds, as they produced lower amounts of metabolites for one of the three peaks demonstrated and had higher diclofenac exposure. This pilot study supports the hypothesis that CYP metabolism is varied amongst bird species and may explain the higher resilience to diclofenac in the chicken versus vultures.

PLLA Coating of Active Implants for Dual Drug Release.

Cochlear implants, like other active implants, rely on precise and effective electrical stimulation of the target tissue but become encapsulated by different amounts of fibrous tissue. The current study aimed at the development of a dual drug release from a PLLA coating and from the bulk material to address short-term and long-lasting release of anti-inflammatory drugs. Inner-ear cytocompatibility of drugs was studied in vitro. A PLLA coating (containing diclofenac) of medical-grade silicone (containing 5% dexamethasone) was developed and release profiles were determined. The influence of different coating thicknesses (2.5, 5 and 10 µm) and loadings (10% and 20% diclofenac) on impedances of electrical contacts were measured with and without pulsatile electrical stimulation. Diclofenac can be applied to the inner ear at concentrations of or below 4 × 10-5 mol/L. Release of dexamethasone from the silicone is diminished by surface coating but not blocked. Addition of 20% diclofenac enhances the dexamethasone release again. All PLLA coatings serve as insulator. This can be overcome by using removable masking on the contacts during the coating process. Dual drug release with different kinetics can be realized by adding drug-loaded coatings to drug-loaded silicone arrays without compromising electrical stimulation.

Microchannel-embedded implantable device with fibrosis suppression for prolonged controlled drug delivery.

For the prolonged, controlled delivery of systemic drugs, we propose an implantable drug-delivery chip (DDC) embedded with pairs of a microchannel and drug-reservoir serving as a drug diffusion barrier and depot, respectively. We pursued a DDC for dual drugs: a main-purpose drug, diclofenac (DF), for systemic exposure, and an antifibrotic drug, tranilast (TR), for local delivery. Thus, the problematic fibrotic tissue formation around the implanted device could be diminished, thereby less hindrance in systemic exposure of DF released from the DDC. First, we separately prepared DDCs for DF or TR delivery, and sought to find a proper microchannel length for a rapid onset and sustained pattern of drug release, as well as the required drug dose. Then, two distinct DDCs for DF and TR delivery, respectively, were assembled to produce a Dual_DDC for the concurrent delivery of DF and TR. When the Dual_DDC was implanted in living rats, the DF concentration in blood plasma did not drop significantly in the later periods after implantation relative to that in the early periods before fibrotic tissue formation. When the Dual_DDC was implanted without TR, there was a significant decrease in the blood plasma DF concentration as the time elapsed after implantation. Biopsied tissues around the Dual_DDC exhibited a significant decrease in the fibrotic capsule thickness and collagen density relative to the Dual_DDC without TR, owing to the effect of the local, sustained release of the TR.

Skin pharmacokinetics of diclofenac and co-delivered functional excipients.

An important question in the development of a dermatological drug product is whether a target concentration has been achieved in, for example, the viable epidermis following topical administration. When attempting to address this challenge, it is essential to consider the role of excipients in the formulation that may influence drug partitioning and diffusion in the different layers of the skin. The objective, therefore, was to correlate, in human subjects, the skin pharmacokinetics of diclofenac (specifically, its uptake into and clearance from the stratum corneum (SC)) from an approved drug product (Voltaren® medicated plaster) with the in vivo co-uptake of two key excipients, namely propylene glycol and butylene glycol. SC sampling was used to assess diclofenac input into the skin during patch application, and its subsequent clearance post-removal of the delivery system. In parallel the uptake of the two glycol excipients was also measured. Drug and excipient amounts in the SC increased with time of application up to 6 h and, for diclofenac, no further increase was observed when the administration was prolonged to 12 h. When the plaster was removed after 6 h of wear, diclofenac cleared relatively slowly from the SC suggesting that drug binding with a slow off-rate had occurred. The results indicate that the optimisation of drug delivery from a topical formulation must take into account the disposition of key excipients and their impact on dermato-pharmacokinetics in general.

Solid-phase microextraction for assessment of plasma protein binding, a complement to rapid equilibrium dialysis.

Aim: Determination of plasma protein binding (PPB) is considered vital for better understanding of pharmacokinetic and pharmacodynamic activities of drugs due to the role of free concentration in pharmacological response. Methodology & results: Solid-phase microextraction (SPME) was investigated for measurement of PPB from biological matrices and compared with a gold standard approach (rapid equilibrium dialysis [RED]). Discussion & conclusion: SPME-derived values of PPB correlated well with literature values, and those determined by RED. Respectively, average protein binding across three concentrations by RED and SPME was 33.1 and 31.7% for metoprolol, 89.0 and 86.6% for propranolol and 99.2 and 99.0% for diclofenac. This study generates some evidence for SPME as an alternative platform for the determination of PPB.

Drug-drug interaction between diclofenac and gamma-hydroxybutyric acid.

Gamma hydroxybutyric acid (GHB) has been approved clinically to treat excessive daytime sleepiness and cataplexy in patients with narcolepsy, alcohol and opioid withdrawal, and as an anesthetic. The use of GHB clinically is limited due to its high abuse potential. The absorption, clearance and tissue uptake of GHB is mediated by proton-dependent and sodium-coupled monocarboxylate transporters (MCTs and SMCTs) and inhibition of these transporters may result in a change in GHB pharmacokinetics and pharmacodynamics. Previous studies have reported that non-steroidal anti-inflammatory drugs (NSAIDs) may inhibit these monocarboxylate transporters. Therefore, the purpose of this work was to analyze the interaction between GHB (at a dose of 600 mg/kg i. v.) and the NSAID, diclofenac, by examining the effects of this drug on the in vivo pharmacokinetics and pharmacodynamics in rat studies. The pharmacodynamic effect evaluated was respiratory depression, a measure of toxicity observed by GHB at this dose. There was an improvement in the respiratory rate with diclofenac administration suggesting an effect of diclofenac on GHB toxicity. In vitro studies with rat blood brain endothelial cells (RBE4) that express MCT1 indicated that diclofenac can inhibit GHB transport with an IC50 of 10.6 µM at pH 7.4. In vivo studies found a decrease in brain GHB concentrations and a decrease in the brain-to-plasma concentration ratio following diclofenac treatment. With this study we can conclude that diclofenac and potentially other NSAIDs can inhibit the transport of GHB into the brain, therefore decreasing GHB's pharmacodynamic effects and toxicity.

Conformable hierarchically engineered polymeric micromeshes enabling combinatorial therapies in brain tumours.

The poor transport of molecular and nanoscale agents through the blood-brain barrier together with tumour heterogeneity contribute to the dismal prognosis in patients with glioblastoma multiforme. Here, a biodegradable implant (µMESH) is engineered in the form of a micrometre-sized poly(lactic-co-glycolic acid) mesh laid over a water-soluble poly(vinyl alcohol) layer. Upon poly(vinyl alcohol) dissolution, the flexible poly(lactic-co-glycolic acid) mesh conforms to the resected tumour cavity as docetaxel-loaded nanomedicines and diclofenac molecules are continuously and directly released into the adjacent tumour bed. In orthotopic brain cancer models, generated with a conventional, reference cell line and patient-derived cells, a single µMESH application, carrying 0.75 mg kg-1 of docetaxel and diclofenac, abrogates disease recurrence up to eight months after tumour resection, with no appreciable adverse effects. Without tumour resection, the µMESH increases the median overall survival (∼30 d) as compared with the one-time intracranial deposition of docetaxel-loaded nanomedicines (15 d) or 10 cycles of systemically administered temozolomide (12 d). The µMESH modular structure, for the independent coloading of different molecules and nanomedicines, together with its mechanical flexibility, can be exploited to treat a variety of cancers, realizing patient-specific dosing and interventions.

Influence of Proteome Profiles and Intracellular Drug Exposure on Differences in CYP Activity in Donor-Matched Human Liver Microsomes and Hepatocytes.

Human liver microsomes (HLM) and human hepatocytes (HH) are important in vitro systems for studies of intrinsic drug clearance (CLint) in the liver. However, the CLint values are often in disagreement for these two systems. Here, we investigated these differences in a side-by-side comparison of drug metabolism in HLM and HH prepared from 15 matched donors. Protein expression and intracellular unbound drug concentration (Kpuu) effects on the CLint were investigated for five prototypical probe substrates (bupropion-CYP2B6, diclofenac-CYP2C9, omeprazole-CYP2C19, bufuralol-CYP2D6, and midazolam-CYP3A4). The samples were donor-matched to compensate for inter-individual variability but still showed systematic differences in CLint. Global proteomics analysis outlined differences in HLM from HH and homogenates of human liver (HL), indicating variable enrichment of ER-localized cytochrome P450 (CYP) enzymes in the HLM preparation. This suggests that the HLM may not equally and accurately capture metabolic capacity for all CYPs. Scaling CLint with CYP amounts and Kpuu could only partly explain the discordance in absolute values of CLint for the five substrates. Nevertheless, scaling with CYP amounts improved the agreement in rank order for the majority of the substrates. Other factors, such as contribution of additional enzymes and variability in the proportions of active and inactive CYP enzymes in HLM and HH, may have to be considered to avoid the use of empirical scaling factors for prediction of drug metabolism.

Physicomechanical, stability, and pharmacokinetic evaluation of aceclofenac dimethyl urea cocrystals.

Poor physicomechanical properties and limited aqueous solubility restrict the bioavailability of aceclofenac when given orally. To improve its above properties, aceclofenac (ACE) was cocrystallized with dimethyl urea (DMU) in 1:2 molar ratio by dry and solvent assisted grinding. The cocrystals were characterized by ATR-FTIR, DSC, and PXRD, and their surface morphology was studied by SEM. There was enhancement in intrinsic dissolution rate (IDR) (~eight- and ~fivefold in cocrystals prepared by solvent assisted grinding (SAG) and solid state grinding (SSG), respectively, in 0.1 N HCl, pH 1.2) and similarly (~3.42-fold and ~1.20-fold in phosphate buffer, pH 7.4) as compared to pure drug. Additionally, mechanical properties were assessed by tabletability curves. The tensile strength of ACE was < 1 MPa in contrast to the cocrystal tensile strength (3.5 MPa) which was ~1.98 times higher at 6000 psi. The tablet formulation of cocrystal by direct compression displayed enhanced dissolution profile (~36% in 0.1 N HCl, pH 1.2, and ~100% in phosphate buffer, pH 7.4) in comparison to physical mixture (~ 30% and ~ 80%) and ACE (~18% and ~50%) after 60 min, respectively. Stability studies of cocrystal tablets for 3 months indicated a stable formulation. Pharmacokinetic studies were performed by using rabbit model. The AUC0-∞ (37.87±1.3 µgh/ml) and Cmax (6.94±2.94 µg/ml) of the selected cocrystal C1 prepared by SAG were significantly enhanced (p < 0.05) and were ~3.43 and ~1.63-fold higher than that of ACE. In conclusion, new cocrystal of ACE-DMU was successfully prepared with improved tabletability, in vitro and in vivo properties.

Physiologically-based pharmacokinetic modeling to support bioequivalence and approval of generic products: A case for diclofenac sodium topical gel, 1.

Establishing bioequivalence (BE) for dermatological drug products by conducting comparative clinical end point studies can be costly and the studies may not be sufficiently sensitive to detect certain formulation differences. Quantitative methods and modeling, such as physiologically-based pharmacokinetic (PBPK) modeling, can support alternative BE approaches with reduced or no human testing. To enable PBPK modeling for regulatory decision making, models should be sufficiently verified and validated (V&V) for the intended purpose. This report illustrates the US Food and Drug Administration (FDA) approval of a generic diclofenac sodium topical gel that was based on a totality of evidence, including qualitative and quantitative sameness and physical and structural similarity to the reference product, an in vivo BE study with PK end points, and, more importantly, for the purposes of this report, a virtual BE assessment leveraging dermal PBPK modeling and simulation instead of a comparative clinical end point study in patients. The modeling approach characterized the relationship between systemic (plasma) and local (skin and synovial fluid) diclofenac exposure and demonstrated BE between the generic and reference products at the presumed site of action. Based on the fit-for-purpose modeling principle, the V&V process involved assessing observed data of diclofenac concentrations in skin tissues and plasma, and the overall performance of the modeling platform for relevant products. Using this case as an example, this report provides current scientific considerations on good practices for model V&V and the establishment of BE for dermatological drug products when leveraging PBPK modeling and simulation for regulatory decision making.

Theoretical model for the diclofenac release from PEGylated chitosan hydrogels.

Controlled drug delivery systems are of utmost importance for the improvement of drug bioavailability while limiting the side effects. For the improvement of their performances, drug release modeling is a significant tool for the further optimization of the drug delivery systems to cross the barrier to practical application. We report here on the modeling of the diclofenac sodium salt (DCF) release from a hydrogel matrix based on PEGylated chitosan in the context of Multifractal Theory of Motion, by means of a fundamental spinor set given by 2 × 2 matrices with real elements, which can describe the drug-release dynamics at global and local scales. The drug delivery systems were prepared by in situ hydrogenation of PEGylated chitosan with citral in the presence of the DCF, by varying the hydrophilic/hydrophobic ratio of the components. They demonstrated a good dispersion of the drug into the matrix by forming matrix-drug entities which enabled a prolonged drug delivery behavior correlated with the hydrophilicity degree of the matrix. The application of the Multifractal Theory of Motion fitted very well on these findings, the fractality degree accurately describing the changes in hydrophilicity of the polymer. The validation of the model on this series of formulations encourages its further use for other systems, as an easy tool for estimating the drug release toward the design improvement. The present paper is a continuation of the work 'A theoretical mathematical model for assessing diclofenac release from chitosan-based formulations,' published in Drug Delivery Journal, 27(1), 2020, that focused on the consequences induced by the invariance groups of Multifractal Diffusion Equations in correlation with the drug release dynamics.

Antinociceptive Interaction and Pharmacokinetics of the Combination Treatments of Methyleugenol Plus Diclofenac or Ketorolac.

Although nonsteroidal anti-inflammatory drugs (NSAIDs) are one of the main types of drugs used to treat pain, they have several adverse effects, and such effects can be reduced by combining two analgesic drugs. The aim of this study was to evaluate the nociceptive activity of methyleugenol combined with either diclofenac or ketorolac, and determine certain parameters of pharmacokinetics. For the isobolographic analysis, the experimental effective dose 30 (ED30) was calculated for the drugs applied individually. With these effective doses, the peak plasma concentration (Cmax) was found and the other parameters of pharmacokinetics were established. Methyleugenol plus diclofenac and methyleugenol plus ketorolac decreased licking behavior in a dose-dependent manner in phase II, with an efficacy of 32.9 ± 9.3 and 39.8 ± 9.6%, respectively. According to the isobolographic analysis, the experimental and theoretical ED30 values were similar for methyleugenol plus diclofenac, suggesting an additive effect, but significantly different for methyleugenol plus ketorolac (3.6 ± 0.5 vs. 7.7 ± 0.6 mg/kg, respectively), indicating a probable synergistic interaction. Regarding pharmacokinetics, the only parameter showing a significant difference was Cmax for the methyleugenol plus diclofenac combination. Even with this difference, the combinations studied may be advantageous for treating inflammatory pain, especially for the combination methyleugenol plus ketorolac.

Development of a method to determine cytochrome P450 1A2, 2C9, 2D6 and 3A4 activity sheep hepatic microsomes.

INTRODUCTION: Ex vivo studies of human fetal hepatic drug metabolism are uncommon as it requires access to functional liver tissue and therefore raises practical and ethical concerns. Large animal models provide an alternative opportunity to study changes in cytochrome P450 (CYP) activity in the mother and fetus during pregnancy. We aimed to develop methods to determine the activity of CYP1A2, CYP2C9, CYP2D6 and CYP3A4 in sheep hepatic microsomes. METHODS: We identified optimal conditions to determine the activity of CYP1A2 (using the probe drug phenacetin), CYP2C9 (diclofenac), CYP2D6 (dextromethorphan) and CYP3A4 (midazolam) by varying techniques for microsome extraction, probe drug concentration, incubation time and microsome concentration. The specificity of each probe drug was assessed by determining the rate of metabolism when specific CYP enzyme inhibitors were included in the reaction. RESULTS: The optimum incubation time and probe drug concentration was six hours with 5 µM phenacetin (CYP1A2), four hours with 10 µM diclofenac (CYP2C9), 30 min with 1 µM of midazolam (CYP3A4) and 10 min with 1 µM dextromethorphan (CYP2D6). For both CYP2D6 and CYP3A4 reactions required 20 µg of microsomal protein, whereas for CYP1A2 and CYP2C9, reactions required 40 µg of microsomal protein. Metabolism of phenacetin, dextromethorphan and midazolam was reduced by specific enzyme inhibitors, but the specific CYP2C9 inhibitor sulfaphenazole did not substantially inhibit diclofenac metabolism. DISCUSSION: This study identifies the optimal conditions for determining CYP activity in maternal sheep hepatic microsomes. In doing so, we have developed a standardised protocol for assessment of microsomal activity of CYP3A4, CYP1A2 and CYP2D6, but we were unable to optimise conditions for assessment of CYP2C9. This approach can be applied to investigate the impact of pregnancy complications on maternal and fetal hepatic drug metabolism.

Pharmacokinetics and bioequivalence assessment of optimized directly compressible Aceclofenac (100 mg) tablet formulation in healthy human subjects.

The aim of the study was to determine the various pharmacokinetic parameters of the newly developed cost-effective aceclofenac 100 mg tablet formulation (F-15) and to establish the bioequivalence against the marketed brand (ACEMED). Both products (test and reference) were given to 12 healthy non-smokers male subjects with overnight fasting of >10hr. The study was a randomized, single-dose, open-label, two sequence, and two treatment crossover design, with a washout period of 2 weeks. Blood samples (5 mL) from the human subjects were collected before (0 hr) and after drug administration at 13different time points (0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 5, 6, 8, 12 and 18 hrs). The drug plasma concentration was analyzed by a validated RP-HPLC method using a solvent system containing acetonitrile and deionized water (60:40% v/v). Linearity was found to be 0.999 over the drug concentration range of 50µg/mL to 0.05µg/mL with LLOQ and LOD of 0.05µg/mL and 0.025µg/mL respectively. Non-compartmental pharmacokinetic analysis was performed using Kinetica® (ver. 5.1) software. Using the log-transformed data Cmax, AUC0-t, AUC0-∞, AUMCtot, and MRT were calculated. The Cmax of the test and brand was found to be 8.629±1.251µg/mL and 8.478±0.913µg/mL. The AUC0-t and AUC0-∞ of the test and the reference were computed to be 20.890 ±2.2021µg/mL.h, 23.272 ±1.914 µg/mL.h and 19.850 ±2.911 µg/mL.h, 22.890 ± 2.110 µg/mL.h correspondingly. Two-way analysis of variance (ANOVA) test and two one-sided t-test (p>0.05; non-significant) were applied to assess the variation in the period, sequence, subjects, and treatment. Geometric mean ratios for above mentioned pharmacokinetic parameters of reference/test were found within the acceptable FDA limits of 80-125% using 90% CI. There was no inter and intrasubject variation (p> 0.05) that was observed. Therefore, the directly compressible aceclofenac (100 mg) test formulation and the commercial reference tablets were declared to be biosimilar.

Pullulan derivative with cationic and hydrophobic moieties as an appropriate macromolecule in the synthesis of nanoparticles for drug delivery.

A new amphiphilic pullulan derivative (DBAP-PO) was obtained by grafting tertiary butyl amine and octanoyl groups on the pullulan backbone as cationic and hydrophobic moieties, respectively. The structural characteristics of the modified polymer were investigated by FT-IR and 1H and 13C NMR spectroscopy. The self-association ability in aqueous solution of DBAP-PO was studied by viscosity and fluorescence methods. The intrinsic viscosity of the polymer was determined by Wolf model. The critical aggregation concentration (CAC) value of 0.028 g/dL, determined by fluorescence measurements in the presence of pyrene, was confirmed by capillary viscosimetry and dynamic laser scattering (DLS). Dialysis method was used to demonstrate the capacity of the pullulan derivative to form spherical nanoparticles (d ~ 200 nm) loaded with model drug, sodium diclofenac (DF) (74% entrapment efficiency). The DF release was sustained and pH-dependent. In vitro cytotoxicity as well as morphological studies conducted on the human skin fibroblasts showed that DBAP-PO/DF nanoparticles do not exhibit cytotoxic effects at the pharmacologically relevant concentration of DF, maintaining the typical morphology of the cells.

ß-Glycerol phosphate/genipin chitosan hydrogels: A comparative study of their properties and diclofenac delivery.

Thermosensitive hydrogels based on polysaccharides are suitable candidates for the design of biodegradable and biocompatible injectable drug delivery systems. Thus, the combination of chitosan (CHI) and ß-glycerol phosphate disodium salt (ß-GP) has been intensively investigated to develop thermo-induced physical gels. With the aim of exploring the possibilities of optimization of these hydrogels, in this work, chitosan, ß-GP and naturally extracted crosslinking agent, genipin (GEN), have been successfully combined, obtaining co-crosslinked hydrogels with both in situ physical and covalent crosslinking. A wide range of ß-GP concentrations have been selected in order to analyze its influence on a variety of properties, including gelation time, pore size, water uptake ability, in vitro hydrolytic and enzymatic degradation, mucoadhesion and mechanical and rheological properties. Furthermore, the potential application of the developed systems for the administration and controlled release of an anti-inflammatory anionic drug, such as diclofenac, has been successfully demonstrated.