Comparison of a revaprazan-loaded solid dispersion, solid SNEDDS and inclusion compound: Physicochemical characterisation and pharmacokinetics

Establishment of nanoparticle screening technique: A pivotal role of sodium carboxymethylcellulose in enhancing oral bioavailability of poorly water-soluble aceclofenac

A novel nanoparticle screening technique was established to mostly enhance the aqueous solubility and oral bioavailability of aceclofenac using nanoparticle systems. Among the polymers investigated, sodium carboxymethylcellulose (Na-CMC) showed the greatest increase in drug solubility. Utilizing spray-drying technique, the solvent-evaporated solid dispersion (SESD), surface-attached solid dispersion (SASD), and solvent-wetted solid dispersion (SWSD) were prepared using aceclofenac and Na-CMC at a weight ratio of 1:1 in 50 % ethanol, distilled water, and ethanol, respectively. Using Na-CMC as a solid carrier, an aceclofenac-loaded liquid self-emulsifying drug delivery system was spray-dried and fluid-bed granulated together with microcrystalline cellulose, producing a solid self-nanoemulsifying drug delivery system (SNEDDS) and solid self-nanoemulsifying granule system (SNEGS), respectively. Their physicochemical properties and preclinical assessments in rats were performed. All nanoparticles exhibited very different properties, including morphology, crystallinity, and size. As a result, they significantly enhanced the solubility, dissolution, and oral bioavailability in the following order: SNEDDS ≥ SNEGS > SESD ≥ SASD ≥ SWSD. Based on our screening technique, the SNEDDS was selected as the optimal nanoparticle with the highest bioavailability of aceclofenac. Thus, our nanoparticle screening technique should be an excellent guideline for solubilization research to improve the solubility and bioavailability of many poorly water-soluble bioactive materials.

Modification of microenvironmental pH of nanoparticles for enhanced solubility and oral bioavailability of poorly water-soluble celecoxib

This study aimed to develop a novel pH-modified nanoparticle with improved solubility and oral bioavailability of poorly water-soluble celecoxib by modifying the microenvironmental pH. After assessing the impact of hydrophilic polymers, surfactants and alkaline pH modifiers on the drug solubility, copovidone, sodium lauryl sulfate (SLS) and meglumine were chosen. The optimal formulation of solvent-evaporated, surface-attached and pH-modified nanoparticles composed of celecoxib/copovidone/SLS/meglumine at weight ratios of 1:1:0.2:0, 1:0.375:1.125:0 and 1:1:1:0.2:0.02, respectively, were manufactured using spray drying technique. Their physicochemical characteristics, solubility, dissolution and pharmacokinetics in rats were evaluated compared to the celecoxib powder. The solvent-evaporated and pH-modified nanoparticles converted a crystalline to an amorphous drug, resulting in a spherical shape with a reduced particle size compared to celecoxib powder. However, the surface-attached nanoparticles with insignificant particle size exhibited the unchangeable crystalline drug. All of them gave significantly higher solubility, dissolution, and oral bioavailability than celecoxib powder. Among them, the pH-modified nanoparticles demonstrated the most significant improvement in solubility (approximately 1600-fold) and oral bioavailability (approximately 4-fold) compared to the drug powder owing to the alkaline microenvironment formation effect of meglumine and the conversion to the amorphous drug. Thus, the pH-modified nanoparticle system would be a promising strategy for improving the solubility and oral bioavailability of poorly water-soluble and weakly acidic celecoxib.

A cochleate formulation optimized by D-optimal mixture design enhances oral bioavailability of Revaprazan

A cochleate formulation was developed to enhance the oral bioavailability of revaprazan (RVP). Dimyristoyl phosphatidylcholine (DMPC) liposome containing dicetyl phosphate (DCP) successfully formed a cochleate after treatment with CaCl2, whereas that containing sodium deoxycholate did not. Cochleate was optimised using a D-optimal mixture design with three independent variables-DMPC (X1, 70.58 mol%), cholesterol (X2, 22.54 mol%), and DCP (X3, 6.88 mol%)-and three response variables: encapsulation efficiency (Y1, 76.92%), released amount of free fatty acid at 2 h (Y2, 39.82%), and released amount of RVP at 6 h (Y3, 73.72%). The desirability function was 0.616, showing an excellent agreement between the predicted and experimental values. The cylindrical morphology of the optimised cochleate was visualised, and laurdan spectroscopy confirmed the dehydrated membrane interface, showing an increased generalised polarisation value (approximately 0.5) over small unilamellar vesicle of RVP (RVP-SUV; approximately 0.1). The optimised cochleate showed greater resistance to pancreatic enzyme than RVP-SUV. RVP was released in a controlled manner, achieving approximately 94% release in 12 h. Following oral administration in rats, the optimised cochleate improved the relative bioavailability of RVP by approximately 274%, 255%, and 172% compared to RVP suspension, a physical mixture of RVP and the cochleate, and RVP-SUV, respectively. Thus, the optimised cochleate formulation might be a good candidate for the practical development of RVP.

Development and evaluation of the in vitro schistosomicidal activity of solid dispersions based on 2-(-5-bromo-1-H-indole-3-yl-methylene)-N-(naphthalene-1-ylhydrazine-carbothiamide

Among all the neglected diseases, schistosomiasis is considered the second most important parasitic infection after malaria. Praziquantel is the most widely used drug for this disease, but its exclusive use may result in the development of drug-resistant schistosomiasis. To increase the control of the disease, new drugs have been developed as alternative treatments, among them 2-(-5-bromo-1-h-indole-3-yl-methylene)-N-(naphthalene-1-ylhydrazine-carbothiamide (LQIT/LT-50), which showed promising schistosomicidal activity in nonclinical studies. However, LQIT/LT-50 presents low solubility in water, resulting in reduced bioavailability. To overcome this solubility problem, the present study aimed to develop LQIT/LT-50 solid dispersions for the treatment of schistosomiasis. Solid dispersions were prepared through the solvent method using Soluplus©, polyethylene glycol (PEG) or polyvinylpyrrolidone (PVP K-30) as hydrophilic carriers. The formulations with the best results in the compatibility tests, aqueous solubility and preliminary stability studies have undergone solubility tests and physicochemical characterizations by Fourier-transform infrared spectroscopy (FTIR), x-ray diffractometry (XRD), exploratory differential calorimetry (DSC), thermogravimetry (TG) and Raman spectroscopy. Finally, the schistosomicidal activity was evaluated in vitro. The phycochemical analyzes showed that when using PVP K-30, there was an interaction between the PVP K-30 and LQIT/LT-50, proving the successful development of the solid dispersion. Furthermore, an increase in the solubility of the new system was observed (LQIT/LT-50:PVP K-30) in addition to the improvement in the in vitro shistosomidal activity at 1:4 (w/w) molar ratio (i.e., 20% drug loading) when compared to LQIT/LT-50 alone. The development of the LQIT/LT-50:PVP K-30 1:4 solid dispersion is encouraging for the future development of new pharmaceutical solid formulations, aiming the schistosomicidal treatment.

Sodium alginate-based smart gastro-retentive drug delivery system of revaprazan loaded SLNs; Formulation and characterization

Revaprazan (REV), a novel reversible Proton Pump Inhibitor (PPI) used to treat peptic ulcers, faces challenges in therapeutic efficacy due to its poor dissolution properties and a short half-life. Solid lipid nanoparticles (SLNs) have emerged as a drug delivery system capable of enhancing dissolution and bioavailability of lipid soluble drugs. Here, we report on the development and optimization of a smart gastro-retentive raft system of REV-loaded SLNs (GRS/REV-SLNs) to enhance drug bioavailability and gastric retention. The optimized REV-SLNs had a particle size of 120 nm, a Polydispersity Index (PDI) of 0.313, a zeta potential of -20.7 mV, and efficient drug incorporation of 88 %. Transmission Electron Microscopy (TEM) affirmed the spherical morphology of these REV-SLNs, while Fourier Transform Infrared Spectroscopy (FTIR) revealed no chemical interactions among components. In-vitro assessment of the final GRS/REV-SLNs demonstrated sustained gelation and buoyancy for over 12 h, which would significantly enhance REV retention and its release within the stomach. Further assessments in rats confirmed successful gel transformation within the stomach, resulting in the improved bioavailability of REV. Thus, the development of GRS/REV-SLNs significantly improved the delivery and bioavailability of REV within the stomach, and offers a potentially improved method of treating peptic ulcers.

Cataleptogenic Effect of Haloperidol Formulated in Water-Soluble Calixarene-Based Nanoparticles

In this study, a water-soluble form of haloperidol was obtained by coaggregation with calix[4]resorcinol bearing viologen groups on the upper rim and decyl chains on the lower rim to form vesicular nanoparticles. The formation of nanoparticles is achieved by the spontaneous loading of haloperidol into the hydrophobic domains of aggregates based on this macrocycle. The mucoadhesive and thermosensitive properties of calix[4]resorcinol–haloperidol nanoparticles were established by UV-, fluorescence and CD spectroscopy data. Pharmacological studies have revealed low in vivo toxicity of pure calix[4]resorcinol (LD50 is 540 ± 75 mg/kg for mice and 510 ± 63 mg/kg for rats) and the absence of its effect on the motor activity and psycho-emotional state of mice, which opens up a possibility for its use in the design of effective drug delivery systems. Haloperidol formulated with calix[4]resorcinol exhibits a cataleptogenic effect in rats both when administered intranasally and intraperitoneally. The effect of the intranasal administration of haloperidol with macrocycle in the first 120 min is comparable to the effect of commercial haloperidol, but the duration of catalepsy was shorter by 2.9 and 2.3 times (p < 0.05) at 180 and 240 min, respectively, than that of the control. There was a statistically significant reduction in the cataleptogenic activity at 10 and 30 min after the intraperitoneal injection of haloperidol with calix[4]resorcinol, then there was an increase in the activity by 1.8 times (p < 0.05) at 60 min, and after 120, 180 and 240 min the effect of this haloperidol formulation was at the level of the control sample.

Functional Excipients and Novel Drug Delivery Scenario in Self-nanoemulsifying Drug Delivery System: A Critical Note

Lipid-based formulations have emerged as prospective dosage forms for extracting the therapeutic effects of existing lipophilic compounds and novel chemical entities more efficiently. Compared to other excipients, lipids have the added benefit of enhancing the bioavailability of lipophilic and highly metabolizable drugs due to their unique physicochemical features and similarities to in vivo components. Furthermore, lipids can minimize the needed dose and even the toxicity of drugs with poor aqueous solubility when employed as the primary excipient. Hence, the aim of the present review is to highlight the functional behavior of lipid excipients used in SNEDD formulation along with the stability aspects of the formulation in vivo. Moreover, this review also covered the importance of SNEDDS in drug delivery, the therapeutic and manufacturing benefits of lipids as excipients, and the technological advances made so far to convert liquid to solid SNEDDS like melt granulation, adsorption on solid support, spray cooling, melt extrusion/ spheronization has also highlighted. The mechanistic understanding of SNEDD absorption in vivo is highly complex, which was discussed very critically in this review. An emphasis on their application and success on an industrial scale was presented, as supported by case studies and patent surveys.

Enhanced dissolution and bioavailability of revaprazan using self-nanoemulsifying drug delivery system

A self-nanoemulsifying drug delivery system (SNEDDS) was developed to enhance the dissolution and oral bioavailability (BA) of revaprazan (RVP). Various SNEDDSs containing 200 mg of RVP were formulated using Capmul MCM, Tween 80, and Brij L4, and they were characterized according to their size, polydispersity index, and dissolution behavior. Dissolution rates of all SNEDDS formulations significantly (p <0.05) improved with the formation of nanoemulsion with monodispersity. Formulation D resulted in RVP dissolution exceeding 70% at 2 h. Compared to raw RVP, SNEDDS exhibited a 4.8- to 7.4-fold improved effective permeability coefficient (P_eff) throughout the intestine in the in situ single pass intestinal permeability study and a 5.1-fold increased oral BA in the in vivo oral absorption assessment in rats. To evaluate the degree of lymphatic uptake, cycloheximide (CYC), a chylomicron flowing blocker, was pretreated prior to the experiment. This pretreatment barely affected the absorption of raw RVP; however, it greatly influenced the absorption of SNEDDS, resulting in an approximately 40% reduction in both the P_eff value and oral BA representing lymphatic transport. Thus, we suggest that the SNEDDS formulation is a good candidate for improving oral absorption of RVP through enhanced lymphatic uptake.

Novel dapagliflozin di-L-proline cocrystal-loaded tablet: Preparation, physicochemical characterization, and pharmacokinetics in beagle dogs and mini-pigs

Dapagliflozin base and a commercial dapagliflozin propanediol hydrate cocrystal (DPF-PDHC) were highly hygroscopic and thermally unstable. In this study, to address this limitation, we prepared a novel dapagliflozin di-L-proline cocrystal (DPF-LPC) and evaluated its physicochemical characterization compared with DPF-PDHC. After the preparation of the DPF-LPC-loaded tablet, its dissolution, stability and bioequivalence in beagle dogs and mini-pigs were assessed. DPF-LPC was well prepared with a dapagliflozin base and L-proline in a molar ratio of 1:2. Similar to DPF-PDHC, DPF-LPC was highly lipophilic and crystalline in nature. However, these two cocrystals exhibited different melting points and crystalline structures, indicating their different cocrystal forms. Moreover, DPF-LPC exhibited less hygroscopicity and lower water content than DPF-PDHC. The DPF-LPC-loaded tablet composed of DPF-LPC, Comprecel M102, lactose monohydrate, crospovidone, magnesium stearate, and Opadry (coating) at a weight ratio of 15.6:104.4:100.0:8.0:2.0:7.0, was dissolution-equivalent to the commercial tablet. Moreover, it provided lower impurities than the commercial tablet, indicating its better stability. In the two animals, there were no significant differences in the plasma concentrations, AUC, C_max, and T_max values, suggesting that they were bioequivalent. Therefore, the novel DPF-LPC-loaded tablet with excellent stability and bioequivalence may be used as a potential alternative to the commercial DPF-PDHC-loaded tablet.

New potential application of hydroxypropyl-β-cyclodextrin in solid self-nanoemulsifying drug delivery system and solid dispersion

The purpose of this study was to use hydroxypropyl-β-cyclodextrin (HP-β-CD) as a novel carrier in solid SNEDDS and solid dispersions to enhance the solubility and oral bioavailability of poorly water-soluble dexibuprofen. The novel dexibuprofen-loaded solid SNEDDS was composed of dexibuprofen, corn oil, polysorbate 80, Cremophor® EL, and HP-β-CD at a weight ratio of 45/35/50/15/100. This solid SNEDDS spontaneously formed a nano-emulsion with a size of approximately 120 nm. Unlike the conventional solid SNEDDS prepared with colloidal silica as a carrier, this dexibuprofen-loaded solid SNEDDS exhibited a spherical structure. Similar to the dexibuprofen-loaded solid dispersion prepared with HP-β-CD, the transformation of the crystalline drug to an amorphous state with no molecular interactions were observed in the solid SNEDDS. Compared to the solid dispersion and dexibuprofen powder, solid SNEDDS significantly enhanced drug solubility and AUC. Therefore, HP-β-CD is a novel potential carrier in SNEDDS for improving the oral bioavailability of dexibuprofen.

Comparison of Three Different Aqueous Microenvironments for Enhancing Oral Bioavailability of Sildenafil: Solid Self-Nanoemulsifying Drug Delivery System, Amorphous Microspheres and Crystalline Microspheres

Background

The purpose of this study was to screen various drug delivery systems for improving the aqueous solubility and oral bioavailability of sildenafil. Three representative techniques, solid self-nanoemulsifying drug delivery systems (SNEDDS), amorphous microspheres and crystalline microspheres, were compared.

Methods

Both microspheres systems contained sildenafil:Labrasol:PVP at a weight ratio of 1:1:6. The amorphous microspheres were manufactured using ethanol, while crystalline microspheres were generated using distilled water. Liquid SNEDDS was composed of sildenafil:Labrasol:Transcutol HP:Captex 300 in the ratio of 1:70:15:15 (w:w:w:w). The solidification process in SNEDDS was performed using HDK N20 Pharma as a solid carrier.

Results

The amorphous microspheres appeared spherical with significantly decreased particle size compared to the drug powder. The crystalline microspheres exhibited a rough surface with no major particle-size difference compared with sildenafil powder, indicating that the hydrophilic excipients adhered to the sildenafil crystal. Solid SNEDDS presented a smooth surface, assuming that the oily liquid was adsorbed to the porous solid carrier. According to the physicochemical evaluation, the crystalline state maintained in crystalline microspheres, whereas the crystal state changed to amorphous state in other formulations. Amorphous microspheres, crystalline microspheres and solid SNEDDS produced about 79, 55, 82-fold increased solubility, compared to drug powder. Moreover, the prepared formulations provided a higher dissolution rate (%) and plasma concentration than did the drug powder (performance order; solid SNEDDS ≥ amorphous microspheres ≥ crystalline microspheres > drug powder). Among the formulations, solid SNEDDS demonstrated the highest improvement in oral bioavailability (AUC; 1508.78 ± 343.95 h·ng/mL).

Conclusion

Therefore, solid SNEDDS could be recommended as an oral dosage form for enhancing the oral bioavailability of sildenafil.

Development of rebamipide-loaded spray-dried microsphere using distilled water and meglumine: physicochemical characterization and pharmacokinetics in rats

In this study, a novel rebamipide-loaded spray-dried microsphere (RSM) with enhanced drug solubility and oral bioavailability has been developed utilizing meglumine, an alkalizing agent. The influence of carriers on the drug solubility alone, and the solubility and dissolution of the drug in the RSM was investigated. Among the alkalizing agents and hydrophilic polymers tested, meglumine and polyvinyl alcohol (PVA) showed the highest drug solubility and dissolution rate, respectively. Many RSMs were manufactured with various amounts of meglumine and PVA using distilled water, and their drug solubility and dissolution were determined. The physicochemical properties, dissolution and pharmacokinetics of the chosen RSM in rats were assessed compared to the rebamipide powder and commercial tablet. Among the RSMs tested, the one composed of rebamipide, meglumine and PVA at a weight ratio of 3:1.75:6 showed the highest drug solubility and dissolution. This RSM with a smooth spherical form significantly decreased the particle size and modified the amorphous rebamipide. Furthermore, the drug solubility, dissolution, plasma concentrations, AUC and C_max values of RSM were significantly higher than those of drug powder and commercial tablet. Thus, this RSN system developed with distilled water and meglumine is recommended as an oral water-soluble rebamipide-loaded pharmaceutical product.

Acetaminophen and tramadol hydrochloride-loaded soft gelatin capsule: preparation, dissolution and pharmacokinetics in beagle dogs

The objective of this study was to develop a novel acetaminophen and tramadol hydrochloride-loaded soft capsule (ATSC) with enhanced bioavailability of tramadol. The ATSC was manufactured in a pilot-scale batch size with the capsule contents composed of tramadol, acetaminophen, PEG 400 and Capmul MCM at a weight ratio of 37.5:325:177.5:30. Moreover, its dissolution, stability and pharmacokinetics in beagle dogs were carried out compared to commercial tablet. The dissolved amounts of acetaminophen from the ATSC and commercial tablet were not significantly different. However, compared to the latter, the former had significantly higher dissolution rate of tramadol at the initial times. In beagle dogs, the ATSC provided no significant difference in plasma concentrations and AUC of acetaminophen than did the commercial tablet; however, it significantly improved those of tramadol compared to the other, indicating the enhanced oral bioavailability of tramadol. Compared to the commercial tablet, the ATSC had a larger AUC value for tramadol (55.27 ± 11.06 vs. 92.62 ± 21.52 h·ng/ml). In the accelerated long-term stability, the ATSC offered higher than 96% drug content of acetaminophen and tramadol, suggesting that it was stable for at least six months. Therefore, this ATSC would be a recommendable candidate with enhanced oral bioavailability and excellent stability.

Effects of different physicochemical characteristics and supersaturation principle of solidified SNEDDS and surface-modified microspheres on the bioavailability of carvedilol

In this study, a solidified self-nanoemulsifying drug delivery system (solidified SNEDDS) and surface-modified microspheres were developed for enhancing the oral bioavailability of carvedilol. Based on the aqueous solubility test, liquid SNEDDS was composed of Peceol™ (oil), Tween® 80 (surfactant), and Labrasol® (co-surfactant) at a weight ratio of 25/50/25, generating the smallest nanoemulsion droplet size. Then, carvedilol was added to liquid SNEDDS and spray-dried with Aerosil® to fabricate the solidified SNEDDS. Surface-modified microspheres were manufactured using copovidone (polymer) and Tween® 80 (surfactant) according to aqueous solubility test results. The proper ratio of copovidone and Tween® 80 was determined based on the solubility and dissolution test. Both prepared formulations and carvedilol powder were compared using four different criteria: physicochemical characteristics, solubility, dissolution, and oral bioavailability. For solidified SNEDDS, carvedilol was encapsulated in liquid SNEDDS and absorbed to the Aerosil® surface, leading to the conversion from a crystalline to an amorphous state. However, the drug maintained its crystal form in the surface-modified microspheres. Round and even-sized particles were attached to the rough surfaces of drug, suggesting that hydrophilic carriers adhered to the hydrophobic drug. All formulations significantly improved drug solubility, dissolution, plasma concentrations, C_max, and AUC compared to carvedilol powder. The parameters were ranked in the following order: solidified SNEDDS > surface-modified microspheres > carvedilol powder. As a result, different solubility-increasing mechanisms provided differences in performance. For carvedilol, the formation of a nano-emulsion in solidified SNEDDS resulted in an efficient supersaturated state, leading to improved solubility (~6.1 fold), dissolution (~1.8 fold), and oral bioavailability (~1.4 fold) that was superior to the hydrophilic microenvironment in surface-modified microspheres.

Development of a Solid Supersaturable Micelle of Revaprazan for Improved Dissolution and Oral Bioavailability Using Box-Behnken Design

PURPOSE

To enhance the oral bioavailability of revaprazan (RVP), a novel solid, supersaturable micelle (SSuM) was developed.

METHODS

Surfactants and solid carriers were screened based on a solubility and a flowability test, respectively. Supersaturating agents, including Poloxamer 407 (P407), were screened. The SSuM was optimized using a Box-Behnken design with three independent variables, including Gelucire 44/14:Brij L4 (G44/BL4; X1) and the amounts of Florite PS-10 (FLO; X2) and Vivapur 105 (VP105; X3), and three response variables, ie, dissolution efficiency at 30 min (Y1), dissolution enhancing capacity (Y2), and Carr's index (Y3). The solid state property was evaluated, and a dissolution test was conducted. RVP, Revanex®, solid micelle (P407-free from the composition of SSuM), and SSuM were orally administrated to rats (RVP 20 mg equivalent/kg) for in vivo pharmacokinetic study.

RESULTS

G44 and BL4 showed great solubility, with a critical micelle concentration range of 119.2-333.0 μg/mL. P407 had an excellent supersaturating effect. FLO and VP105 were selected as solid carriers, with a critical solidifying ratio (g/mL) of 0.30 and 0.91, respectively. With optimized values of X1 (-0.41), X2 (0.31), and X3 (-0.78), RVP (200 mg)-containing SSuM consisting of G44 (253.8 mg), BL4 (106.2 mg), FLO (99.3 mg), VP105 (199.8 mg), and P407 (40 mg) was developed, resulting in Y1 (40.3%), Y2 (0.008), and Y3 (12.3%). RVP existed in an amorphous state in the optimized SSuM, and the SSuM formed a nanosized dispersion in the aqueous phase, with approximately 71.7% dissolution at 2 h. The optimized SSuM improved the relative bioavailability of RVP in rats by approximately 478%, 276%, and 161% compared to raw RVP, Revanex®, and solid micelle, respectively.

CONCLUSION

The optimized SSuM has great potential for the development of solidified formulations of poorly water-soluble drugs with improved oral absorption.

Electrospun Gelatin Nanocontainers for Enhanced Biopharmaceutical Performance of Piroxicam: In Vivo and In Vitro Investigations

BACKGROUND

Piroxicam exhibits low oral bioavailability, due to its meager solubility in water. The intent of this study was to ameliorate the bioavailability of the drug by employing a solubility-enhancing encapsulation technique.

METHODS

Seven samples were formulated with piroxicam and gelatin using both solvent evaporation and electrospraying together. Evaluation of solubility and release rate in water and assessment of bioavailability in rats were carried out in comparison with piroxicam plain drug powder (PPDP). Other in vitro explorations were accomplished using powder X-ray diffraction analysis, differential scanning calorimetry, thermogravimetric analysis, scanning electron microscopy, and Fourier-transform infrared spectroscopy.

RESULTS

All piroxicam-loaded gelatinnanocontainers (PLGNs) enhanced solubility and release of the payload in water. In particular, a PLGN formulation consisting of piroxicam and gelatin at a 1:8 (w:w) ratio presented about 600-fold the drug solubility of that shown by PPDP. Moreover, 85.12%±10.96% of the payload was released from this formulation in 10 minutes which was significantly higher than that dissolved from PPDP in 10 minutes (11.81%±5.34%). Drug content, drug loading, and encapsulation efficiency of this formulation were 93.41%±0.56%, 10.45%±0.06%, and 66.74%±6.87%, respectively. The drug loaded in PLGNs existed in the amorphous state, as confirmed by X-ray diffraction and differential scanning-calorimetry analyses, and was more stable when analyzed by thermogravimetric analysis. Moreover, Fourier-transform infrared spectroscopy analysis suggested nonexistence of any piroxicam-gelatin interaction in the formulation. In the scanning electron-microscopy image, PLGNs appeared as round, smooth particles, with particle size of <1,000 nm. Amelioration in bioavailability of piroxicam with the aforementioned PLGN formulation was fourfold that of PPDP.

CONCLUSION

The PLGN formulation fabricated with piroxicam and gelatin at 1:8 (w:w) might be a promising system for enhanced biopharmaceutical performance of the drug.

A Solid Ultra Fine Self-Nanoemulsifying Drug Delivery System (S-SNEDDS) of Deferasirox for Improved Solubility: Optimization, Characterization, and In Vitro Cytotoxicity Studies

The research work was designed to develop a solid self-nanoemulsifying drug delivery system (S-SNEDDS) of deferasirox (DFX). According to the solubility studies of DFX in different components, Peceol, Kolliphor EL, and Transcutol were selected as excipients. Pseudo-ternary phase diagrams were constructed, and then SNEDDS formation assessment studies and solubility of DFX in selected SNEDDSs formulations were performed. DFX loaded SNEDDS were prepared and characterized. The optimum DFX-SNEDDS formulations were developed. The relative safety of the optimized SNEDDS formulation was examined in a human immortalized myelogenous leukemia cell line, K562 cells, using the MTT cell viability test. Cytotoxicity studies revealed more cell viability (71.44%) of DFX loaded SNEDDS compared to pure DFX (3.99%) at 40 μM. The selected DFX-SNEDDS formulation was converted into S-SNEDDS by adsorbing into porous carriers, in order to study its dissolution behavior. The in vitro drug release studies indicated that DFX release (Q5%) from S-SNEDDS solidified with Neusilin UFL2 was significantly higher (93.6 ± 0.7% within 5 min) compared with the marketed product (81.65 ± 2.10%). The overall results indicated that the S-SNEDDS formulation of DFX could have the potential to enhance the solubility of DFX, which would in turn have the potential to improve its oral bioavailability as a safe novel delivery system.

Mechanisms of increased bioavailability through amorphous solid dispersions: a review

Amorphous solid dispersions (ASDs) can increase the oral bioavailability of poorly soluble drugs. However, their use in drug development is comparably rare due to a lack of basic understanding of mechanisms governing drug liberation and absorption in vivo. Furthermore, the lack of a unified nomenclature hampers the interpretation and classification of research data. In this review, we therefore summarize and conceptualize mechanisms covering the dissolution of ASDs, formation of supersaturated ASD solutions, factors responsible for solution stabilization, drug uptake from ASD solutions, and drug distribution within these complex systems as well as effects of excipients. Furthermore, we discuss the importance of these findings on the development of ASDs. This improved overall understanding of these mechanisms will facilitate a rational ASD formulation development and will serve as a basis for further mechanistic research on drug delivery by ASDs.

Development of novel tenofovir disoproxil phosphate salt with stability enhancement and bioequivalence to the commercial tenofovir disoproxil fumarate salt in rats and beagle dogs

Tenofovir disoproxil (TD) is very unstable in the solid state under storage conditions. Moreover, tenofovir disoproxil fumarate (TDF), a commercial salt, is chemically unstable in alkaline solution. In this study, a novel tenofovir disoproxil phosphate (TDP), with stability enhancement and bioequivalence to commercial TDF in rats and beagle dogs, has been developed as an alternative. The TDP and its tablets were easily manufactured, and its physicochemical properties, such as morphology, crystallinity, solubility, lipophilicity and stability were investigated and compared to TD and TDF. Its dissolution and pharmacokinetics were investigated in rats and beagle dogs in comparison to TD and TDF. TDP appeared as an irregularly-shaped crystalline powder with a rough surface, like TDF. However, TDP significantly improved the solubility (7.4 ± 1.3 vs. 28.6 ± 1.0 mg/ml), hydrophilicity (Log P, 0.58 ± 0.03 vs. 0.47 ± 0.04), and aqueous stability (drug concentration over 12 h at pH 6.8 84.0 ± 2.0% vs. 88.2 ± 1.5%) of TD compared to TDF. The TDP gave no significant different plasma concentrations, AUC and C_max compared to TDF in rats (AUC, 1242.1 ± 584.9 vs. 825.9 ± 79.5 h·ng/ml; C_max, 154.8 ± 25.4 vs. 210.9 ± 70.3 ng/ml). Moreover, the TDP-loaded tablets were stable for at least six months and provided similar dissolution and bioequivalence to the TDF-loaded commercial product in beagle dogs (AUC, 26,832.7 ± 4093.0 vs. 26,605.3 ± 2530.1 h·ng/ml; C_max, 4364.0 ± 2061.9 vs. 4186.3 ± 2616.5 ng/ml). Therefore, as an alternative salt, the TDP would be a recommendable candidate with stability enhancement and bioequivalence to the commercial TDF.

Quality by Design Approach for the Development of Self-Emulsifying Systems for Oral Delivery of Febuxostat: Pharmacokinetic and Pharmacodynamic Evaluation

The goal of the present investigation is to formulate febuxostat (FXT) self-nanoemulsifying delivery systems (liquid SNEDDS, solid SNEDDS, and pellet) to ameliorate the solubility and bioavailability. To determine the self-nanoemulsifying region, ternary plot was constructed utilizing Capmul MCM C8 NF® as an oil phase, Labrasol® as principal surfactant, and Transcutol HP® being the co-surfactant. Liquid SNEDDS (L-SNEDDS) were characterized by evaluating droplet size, zeta potential, % transmission, and for thermodynamic stability. In vitro dissolution study of FXT loaded L-SNEDDS (batch F7) showed increased dissolution (about 48.54 ± 0.43% in 0.1 N HCl while 86.44 ± 0.16% in phosphate buffer pH 7.4 within 30 min) compared to plain drug (19.65 ± 2.95% in 0.1 N HCl while about 17.61 ± 2.63% in phosphate buffer pH 7.4 within 30 min). Single pass intestinal permeability studies revealed fourfold increase in the intestinal permeability of F7 compared to plain drug. So, for commercial aspects, F7 was further transformed into solid SNEDDS (S-SNEDDS) as readily nanoemulsifying powder form (SNEP) as well as pellets prepared by application of extruder spheronizer. The developed formulation was found superior to pure FXT with enhanced oral bioavailability and anti-gout activity (with reduced uric acid levels), signifying a lipidic system being an efficacious substitute for gout treatment.

Preparation and evaluation of tacrolimus-loaded thermosensitive solid lipid nanoparticles for improved dermal distribution

Background: Tacrolimus (TCR), also known as FK-506, is a biopharmaceutics classification system (BCS) class II drug that is insoluble in water because of its high log P values. After dermal application, TCR remains in the stratum corneum and passes through the skin layers with difficulty.

Purpose: The objectives of this study were to develop and evaluate solid lipid nanoparticles (SLNs) with thermosensitive properties to improve penetration and retention.

Methods: We prepared TCR-loaded thermosensitive solid lipid nanoparticles (TCR-SLNs) with different types of surfactants on the shell of the particle, which conferred the advantages of enhancing skin permeation and distribution. We also characterized them from a physic point of view and performed in vitro and in vivo evaluations.

Results: The TCR contained in the prepared TCR-SLN was in an amorphous state and entrapped in the particles with a high loading efficiency. The assessment of ex vivo skin penetration using excised rat dorsal skin showed that the TCR-SLNs penetrated to a deeper layer than the reference product (0.1% Protopic^®). In addition, the in vivo skin penetration test demonstrated that TCR-SLNs delivered more drug into deeper skin layers than the reference product. FT-IR images also confirmed drug distribution of TCR-SLNs into deeper layers of the skin.

Conclusion: These results revealed the potential application of thermosensitive SLNs for the delivery of difficult-to-permeate, poorly water-soluble drugs into deep skin layers.

Revaprazan-loaded surface-modified solid dispersion: physicochemical characterization and in vivo evaluation

The purpose of this research was to develop a novel revaprazan-loaded surface-modified solid dispersion (SMSD) with improved drug solubility and oral bioavailability. The impact of carriers on aqueous solubility of revaprazan was investigated. HPMC and Cremophor A25 were selected as an appropriate polymer and surfactant, respectively, due to their high drug solubility. Numerous SMSDs were prepared with various concentrations of carriers, using distilled water, and the drug solubility of each was assessed. Moreover, the physicochemical properties, dissolution and pharmacokinetics of selected SMSD in rats were assessed in comparison to revaprazan powder. Of the SMSDs assessed, the SMSD composed of revaprazan/HPMC/Cremophor A25 at the weight ratio of 1:0.28:1.12 had the most enhanced drug solubility (∼6000-fold). It was characterized by particles with a relatively rough surface, suggesting that the carriers were attached onto the surface of the unchanged crystalline revaprazan powder. It had a significantly higher dissolution rate, AUC and C_max, and a faster T_max value in comparison to revaprazan powder, with a 5.3-fold improvement in oral bioavailability of revaprazan. Therefore, from an environmental perspective, this SMSD system prepared with water, and without organic solvents, should be recommended as a revaprazan-loaded oral pharmaceutical alternative.

Development and Characterization of a Self-Nanoemulsifying Drug Delivery System Comprised of Rice Bran Oil for Poorly Soluble Drugs

Poor aqueous solubility and low bioavailability are limiting factors in the oral delivery of lipophilic drugs. In a formulation approach to overcome these limitations, rice bran (RB) oil was evaluated as drug carrier in the development of self-nanoemulsifying drug delivery systems (SNEDDS). The performance of RB in formulations incorporating Kolliphor RH40 or Kolliphor EL as surfactants and Transcutol HP as cosolvent was compared to a common oil vehicle, corn oil (CO). Serial dilutions of the preconcentrates were performed in various media [distilled water and simulated intestinal fluids mimicking fasted state (FaSSIF) and fed state (FeSSIF)] and at different dilution ratios to simulate the in vivo droplets' behavior. The developed SNEDDS were assessed by means of phase separation, droplet size, polydispersity index, and ζ-potential. Complex ternary diagrams were constructed to identify compositions exhibiting monophasic behavior, droplet size < 100 nm, and polydispersity index (PDI) < 0.25. Multifactor analysis and response surface areas intended to determine the factors significantly affecting droplet size. The oil capacity to accommodate lipophilic drugs was assessed via fluorescence spectroscopy based on the solvatochromic behavior of Nile Red. Solubility studies were performed to prepare fenofibrate- and itraconazole-loaded SNEDDS and assess their droplet size, whereas dissolution experiments were conducted in simulated intestinal fluids. Caco-2 cell viability studies confirmed the safety of the SNEDDS formulations at 1:100 and 1:1000 dilutions after cell exposure in culture for 4 h. The obtained results showed similar performance between RB and CO supporting the potential of RB as oil vehicle for the effective oral delivery of lipophilic compounds.

Novel revaprazan-loaded gelatin microsphere with enhanced drug solubility and oral bioavailability

To develop a novel revaprazan-loaded gelatine microsphere with enhanced solubility and oral bioavailability, numerous gelatine microspheres were prepared using a spray-drying technique. The impact of gelatine amount on drug solubility in the gelatine microspheres was investigated. The physicochemical properties of the selected gelatine microsphere, such as shape, particle size and crystallinity, were evaluated. Moreover, its dissolution and pharmacokinetics in rats were assessed in comparison with revaprazan powder. Amongst the gelatine microspheres tested, the gelatine microsphere consisting of revaprazan and gelatine (1:2, w/w), which gave about 150-fold increased solubility, had the most enhanced drug solubility. It provided a spherical shape, amorphous drug and reduced particle size. Furthermore, it gave a higher dissolution rate and plasma concentration than did revaprazan powder. Particularly, it gave about 2.3-fold improved oral bioavailability in comparison with revaprazan powder. Therefore, this novel gelatine microsphere system is recommended as an oral pharmaceutical product of poorly water-soluble revaprazan.

Different types, applications and limits of enabling excipients of pharmaceutical dosage forms

Along with the development of novel drug delivery systems the material science is also advancing. Conventional and novel synthetic or natural excipients provide opportunities to design dosage forms of the required features including their bioavailability. Emerging trends in the design and development of drug products indicate an increasing need for the functionality-related characterization of excipients. The purpose of this review is to provide an overview of different types of excipients in relation to their application possibilities in various dosage forms with special focus on the enabling excipients. The study also summarizes the applied excipient systems of research formulations and dosage forms available on the market.