Immediate-Release Nifedipine Binary Dry Powder Mixtures with Nanocellulose Featuring Enhanced Solubility and Dissolution Rate

Gelatin-PVP dissolving microneedle-mediated therapy for controlled delivery of nifedipine for rapid antihypertension treatment

Nifedipine has exhibited to be the oldest primary drug having promising therapeutic potential for hypertension, angina pectoris, and pre-eclampsia treatment which are the most emergency serious complications worldwide. Moreover, for long-term treatment transdermal route of delivery using polymeric dissolving microneedles (DMNs) patches has shown greater advantages, thus enhancing treatment compliance, painless, reducing the daily number of doses, prolonged release in a controlled manner, and variable bioavailability making this an ideal candidate for the transdermal therapeutic system. Here, we fabricated DMN patches made of gelatin and PVP using PDMS molds loaded with nifedipine drugs for a controlled painless delivery for a longer stable duration. The prepared gelatin-PVP (gel-PVP) DMN patches loaded with nifedipine were fabricated by centrifugation casting method. The characterization results displayed excellent mechanical strength of the needles to penetrate the skin. SEM and confocal microscopy showed penetration of the needles up to 567-600 µm using rhodamine B applied to the hairless punctured skin site. FTIR study exhibited no degradation of the drug was observed while fabricating the DMNs patch at different pH 7.4 and 4. Skin resealing test proved that there was immediate resealing of the skin observed within 10-15 min. Further in-vitro drug release profile study was carried out by dissolution method at different pH 7.4 and 4 showed sustained release of the drug up to 96 ± 2% till 48-72 h avoiding polymer or drug loss which was quantified by UV vis spectrophotometer at 235 nm absorbance showed stable release of the drug upto 48-72 h. A stability study carried out by the HPLC method showed the DMN patches loaded with the drug were found to be stable for up to 30 days at 25 °C. This novel preliminary data are the first study to our knowledge introducing these fabricated nifedipine gel-PVP DMN patches were found to be very efficient and showed prolonged controlled release up to 48-72 h thereby treating hypertension in a convenient, painless manner. This DMN patch-formulated design might act as a potential approach leading to a controllable, self-administrative, and rapid transdermal delivery system.

Supercritical fluid technology as a strategy for nifedipine solid dispersions formulation: In vitro and in vivo evaluation

Supercritical fluid technology (SFT) is an insufficiently investigated approach for the production of solid dispersions, it is environmentally acceptable and has a high potential for application in the pharmaceutical industry. The aim of this work was to formulate and characterize nifedipine solid dispersions (SDs) produced by the SFT and compare the results with ones obtained by the classical solvent based kneading method. The following in vitro tests were conducted: assay and yield, solvent residues, solid state characterization (FTIR, DSC, XRD), flowability, hygroscopicity, solubility, dissolution and stability. Additionally, bioavailability was examined on an animal model (Wistar rats). The formulation selection for in vivo study was performed using the multilevel categoric experimental design and the health risk assessment. Solid state characterization revealed that formulation obtained by the SFT method and higher ratio of polymer (1:5) have had nifedipine in completely amorphous form. Polymer ratio and method of SDs preparation do influence the investigation characteristics. Dissolution rate was fastest in SDs prepared by the SFT and higher polymer ration (1:5). In vivo data of selected SDs prepared by the kneading (ratio 1:1) and the SFT (ratio 1:5) showed alteration in pharmacokinetic profile after i.v. and p.o. application.

Preparation and Characterization of Nifedipine-Loaded Dry Medium Internal-Phase Emulsions (Dry MIPEs) to Improve Cellular Permeability

A nifedipine (NP) dry emulsion was fabricated by the adsorption of medium internal-phase emulsions (MIPEs). Simple homogenizers were first used to mix conventional liquid MIPEs, and then a microfluidizer was used to reduce the resulting emulsions’ droplet sizes. The dry MIPEs (solid) were produced by adsorbing the emulsions onto solid carriers with a high surface area. The dry MIPEs were diluted in a simulated gastric fluid under gentle agitation to form emulsions. The diluted dry MIPEs were divided into three groups based on an NP content of 0.3%, 0.5%, and 0.7%, with sizes of 5026–5404 nm, 2583–3233 nm, and 1318–1618 nm in diameter, respectively. Powder X-ray diffraction (PXRD) measurements and differential scanning calorimetry (DSC) were used to characterize the physical properties of the dry MIPEs. The samples contained 0.5% or 0.7% drug, 2–4% surfactant, and 8–16% oil (5RH2/8, 7RH2/8, and 7RH4/16) and showed the characteristic peak for NP. No NP peak was observed in formulations with 0.3% NP and any oil-phase content (3RH2/8, 3RH4/16, and 3RH8/32). The formulations with 0.5% drug, 4–8% surfactant, 16–32% oil (5RH4/16 and 5RH8/32) and those with 0.7% drug, 8% surfactant, and 32% oil (7RH8/32) also did not show the peak for NP. These findings demonstrated that microfluidization improved the solubility of NP in the formulations. The subsequent drug dissolution results were consistent with the DSC thermogram and PXRD pattern results. 3RH2/8, 3RH4/16, 3RH8/32, 5RH4/16, 5RH8/32, and 7RH8/32 were completely dissolved and showed higher dissolved NP amounts than 5RH2/8, 7RH2/8, 7RH4/16, and NP powder. The lowest mean dissolution time was for 7RH8/32 (13.31 ± 0.87 min). Caco-2 cells were used to determine drug uptake, and 7RH8/32 showed the maximum intracellular uptake (10.89%). After storage under accelerated and normal conditions (3 and 6 months), the selected formulations remained stable. The developed formulations can be used to improve NP solubility and absorption.

Improvement in Solubility and Absorption of Nifedipine Using Solid Solution: Correlations between Surface Free Energy and Drug Dissolution

Ternary solid solutions composed of nifedipine (NDP), amino methacrylate copolymer (AMCP), and polysorbate (PS) 20, 60, or 65 were prepared using a solvent evaporation method. The dissolution profiles of NDP were used to study the effect of the addition of polysorbate based on hydrophilic properties. A solid solution of NDP and AMCP was recently developed; however, the dissolution of NDP was <70%. In the present study, polysorbate was added to improve the dissolution of the drug by altering its hydrophilicity. The suitable formulation contained NDP and AMCP at a ratio of 1:4 and polysorbate at a concentration of 0.1%, 0.3%, or 0.6%. Differential scanning calorimetry and powder X-ray diffraction were used to examine the solid solutions. No peak representing crystalline NDP was observed in any solid solution samples, suggesting that the drug was molecularly dispersed in AMCP. The NDP dissolution from NDP powder and solid solution without PS were 16.82% and 58.19%, respectively. The highest dissolution of NDP of approximately 95.25% was noted at 120 min for the formulation containing 0.6% PS20. Linear correlations were observed between the surface free energy and percentages of dissolved NDP (R² = 0.7115–0.9315). Cellular uptake across Caco-2 was selected to determine the drug permeability. The percentages of cellular uptake from the NDP powder, solid solution without and with PS20 were 0.25%, 3.60%, and 7.27%, respectively.

Dissolution of amorphous nifedipine from micelle-forming carboxymethylcellulose derivatives

We show that a novel amphiphilic graft copolymer combining the biodegradability and biocompatibility of oxidized carboxymethylcellulose (CMC) with that of hydrophilic poly(ethylene glycol) (PEG), and hydrophobic dodecylamine (DDA), improves the solubility and dissolution performance of nifedipine (NIF), considered as a model hydrophobic drug. The hydrophobic components of the graft copolymer have the multiple effect of favouring micelle formation and loading. At the same time, the interaction between the hydrophobic core and NIF has the secondary effect to suppress drug crystallization, favouring its dissolution, and to increase photostability. Oxidized CMC-g-PEG-DDA micelles reached values of drug concentration, loading capacity and encapsulation efficiency as high as 340 μg mL^-1, 6.4 % and 34.1 %, respectively. Loaded micelles showed a good stability with a limited release profile at pH 1.2, whereas at pH 7.4 the swollen cores enable much higher and progressive release, that reaches 3.4 and 6.6 % after 3 and 5 h, respectively, corresponding to very competitive concentration of 34 and 66 μg mL^-1.

Spray-dried bacterial cellulose nanofibers: A new generation of pharmaceutical excipient intended for intestinal drug delivery

Defibrillation of bacterial cellulose by ultra-refining was efficient to release nanofibers (BCNF) which were spray dried with the matrices formers mannitol (MN), maltodextrin or hydroxypropylmethylcellulose. The best microsystem comprised the association of BCNF and MN, so the selected microparticles were loaded with diclofenac sodium or caffeine. Depending on the proportion of BCNF, the nanofibers collapse promoted by spray drying can occur onto surface or into microparticles core, leading to different release behaviors. Samples showed pH-dependent drug release, so the microsystem developed with the lowest BCNF concentration showed important trend to gastroresistance. Caffeine was spray dried as a free drug and for this reason it was devoid of any control over release rates. The set of results showed BCNF can be considered an interesting and potential pharmaceutical excipient for lipophilic drugs. Beyond that, BCNF association with MN can lead to novel enteric drug delivery systems based on natural polymers.

Dissolution Behavior of Flufenamic Acid in Heated Mixtures with Nanocellulose

Flufenamic acid (FFA) is a problem drug that has up to eight different polymorphs and shows poor solubility. Variability in bioavailability has been reported in the past resulting in limited use of FFA in the oral solid dosage form. The goal of this article was to investigate the polymorphism and amorphization behavior of FFA in non-heated and heated mixtures with high surface area nanocellulose, i.e., Cladophora cellulose (CLAD). As a benchmark, low surface area microcrystalline cellulose (MCC) was used. The solid-state properties of mixtures were characterized with X-ray diffraction, Fourier-transform infrared spectroscopy, and differential scanning calorimetry. The dissolution behavior of mixtures was studied in three biorelevant media, i.e., fasted state simulated gastric fluid, fasted state simulated intestinal fluid, and fed state simulated intestinal fluid. Additional thermal analysis and dissolution tests were carried out following 4 months of storage at 75% RH and room temperature. Heated mixtures of FFA with CLAD resulted in complete amorphization of the drug, whereas that with MCC produced a mixture of up to four different polymorphs. The amorphous FFA mixture with CLAD exhibited rapid and invariable fasted/fed state dissolution in simulated intestinal fluids, whereas that of MCC mixtures was highly dependent on the biorelevant medium. The storage of the heated FFA-CLAD mixture did not result in recrystallization or changes in dissolution profile, whereas heated FFA-MCC mixture showed polymorphic changes. The straightforward dry powder formulation strategy presented here bears great promise for reformulating a number of problem drugs to enhance their dissolution properties and reduce the fasted/fed state variability.

Directly Compressed Tablets of Free Acid Ibuprofen with Nanocellulose Featuring Enhanced Dissolution: A Side-by-Side Comparison with Commercial Oral Dosage Forms

We have previously reported that heated powder mixtures of ibuprofen (IBU) and high surface area nanocellulose exhibit an enhanced dissolution and solubility of the drug due to IBU amorphization. The goal of the present work was to further elaborate the concept and conduct side-by-side in vitro drug release comparisons with commercial formulations, including film-coated tablets, soft gel liquid capsules, and IBU-lysine conjugate tablets, in biorelevant media. Directly compressed tablets were produced from heated mixtures of 20% w/w IBU and high surface area Cladophora cellulose (CLAD), with 5% w/w sodium croscarmelose (AcDiSol) as superdisintegrant. The side-by side studies in simulated gastric fluid, fasted-state simulated intestinal fluid, and fed-state simulated intestinal fluid corroborate that the IBU-CLAD tablets show more rapid and less variable release in various media compared to three commercial IBU formulations. On the sidelines of the main work, a possibility of the presence of a new meta-crystalline form of IBU in mixture with nanocellulose is discussed.

A Liposomal Formulation for Improving Solubility and Oral Bioavailability of Nifedipine

Proliposomes were used to improve the solubility and oral bioavailability of nifedipine. Nifedipine proliposomes were prepared by methanol injection-spray drying method. The response surface method was used to optimize formulation to enhance the encapsulation efficiency (EE%) of nifedipine. The particle size of nifedipine proliposomes after rehydration was 114 nm. Surface morphology of nifedipine proliposomes was observed by a scanning electron microscope (SEM) and interaction of formulation ingredients was assessed by differential scanning calorimetry (DSC). The solubility of nifedipine is improved 24.8 times after forming proliposomes. In vitro release experiment, nifedipine proliposomes had a control release effect, especially in simulated gastric fluid. In vivo, nifedipine proliposomes significantly improved the bioavailability of nifedipine. The area under the concentration-time curve (AUC_0–∞) of nifedipine proliposomes was about 10 times than nifedipine after oral administration. The elimination half-life (T_1/2β) of nifedipine was increased from 1.6 h to 6.6 h. In conclusion, proliposomes was a promising system to deliver nifedipine through oral route and warranted further investigation.

Electrochemical sensors and biosensors based on the use of polyaniline and its nanocomposites: a review on recent advances

Polyaniline and its composites with nanoparticles have been widely used in electrochemical sensor and biosensors due to their attractive properties and the option of tuning them by proper choice of materials. The review (with 191 references) describes the progress made in the recent years in polyaniline-based biosensors and their applications in clinical sensing, food quality control, and environmental monitoring. A first section summarizes the features of using polyaniline in biosensing systems. A subsequent section covers sensors for clinical applications (with subsections on the detection of cancer cells and bacteria, and sensing of glucose, uric acid, and cholesterol). Further sections discuss sensors for use in the food industry (such as for sulfite, phenolic compounds, acrylamide), and in environmental monitoring (mainly pesticides and heavy metal ions). A concluding section summarizes the current state, highlights some of the challenges currently compromising performance in biosensors and nanobiosensors, and discusses potential future directions. Graphical abstract Schematic presentation of electrochemical sensor and biosensors applications based on polyaniline/nanoparticles in various fields of human life including medicine, food industry, and environmental monitoring. The simultaneous use of suitable properties polyaniline and nanoparticles can provide the fabrication of sensing systems with high sensitivity, short response time, high signal/noise ratio, low detection limit, and wide linear range by improving conductivity and the large surface area for biomolecules immobilization.

The Process⁻Property⁻Performance Relationship of Medicated Nanoparticles Prepared by Modified Coaxial Electrospraying

In pharmaceutical nanotechnology, the intentional manipulation of working processes to fabricate nanoproducts with suitable properties for achieving the desired functional performances is highly sought after. The following paper aims to detail how a modified coaxial electrospraying has been developed to create ibuprofen-loaded hydroxypropyl methylcellulose nanoparticles for improving the drug dissolution rate. During the working processes, a key parameter, i.e., the spreading angle of atomization region (θ, °), could provide a linkage among the working process, the property of generated nanoparticles and their functional performance. Compared with the applied voltage (V, kV; D = 2713 - 82V with RθV2 = 0.9623), θ could provide a better correlation with the diameter of resultant nanoparticles (D, nm; D = 1096 - 5θ with RDθ2 = 0.9905), suggesting a usefulness of accurately predicting the nanoparticle diameter. The drug released from the electrosprayed nanoparticles involved both erosion and diffusion mechanisms. A univariate quadratic equation between the time of releasing 95% of the loaded drug (t, min) and D (t = 38.7 + 0.097D - 4.838 × 105D2 with a R2 value of 0.9976) suggests that the nanoparticle diameter has a profound influence on the drug release performance. The clear process-property-performance relationship should be useful for optimizing the electrospraying process, and in turn for achieving the desired medicated nanoparticles.