Reversing the Natural Drug Resistance of Gram-Negative Bacteria to Fusidic Acid via Forming Drug-Phospholipid Complex

Drug resistance substantially compromises antibiotic therapy and poses a serious threat to public health. Fusidic acid (FA) is commonly used to treat staphylococcal infections, such as pneumonia, osteomyelitis and skin infections. However, Gram-negative bacteria have natural resistance to FA, which is almost restrained in cell membranes due to the strong interactions between FA and phospholipids. Herein, we aim to utilize the strong FA-phospholipid interaction to pre-form a complex of FA with the exogenous phospholipid. The FA, in the form of an FA-phospholipid complex (FA-PC), no longer interacts with the endogenous membrane phospholipids and thus can be delivered into bacteria cells successfully. We found that the water solubility of FA (5 µg/mL) was improved to 133 µg/mL by forming the FA-PC (molar ratio 1:1). Furthermore, upon incubation for 6 h, the FA-PC (20 µg/mL) caused a 99.9% viability loss of E. coli and 99.1% loss of P. aeruginosa, while free FA did not work. The morphology of the elongated bacteria cells after treatment with the FA-PC was demonstrated by SEM. The successful intracellular delivery was shown by confocal laser scanning microscopy in the form of coumarin 6-PC (C6-PC), where C6 served as a fluorescent probe. Interestingly, the antibacterial effect of the FA-PC was significantly compromised by adding extra phospholipid in the medium, indicating that there may be a phospholipid-based transmembrane transport mechanism underlying the intracellular delivery of the FA-PC. This is the first report regarding FA-PC formation and its successful reversing of Gram-negative bacteria resistance to FA, and it provides a platform to reverse transmembrane delivery-related drug resistance. The ready availability of phospholipid and the simple preparation allow it to have great potential for clinical use.

Hydrolysis and Transport Characteristics of Phospholipid Complex of Alkyl Gallates: Potential Sustained Release of Alkyl Gallate and Gallic Acid

Phospholipid complexes of alkyl gallates (A-GAs) including ethyl gallate (EG), propyl gallate (PG), and butyl gallate (BG) were successfully prepared by the thin film dispersion method. HPLC-UV analysis in an everted rat gut sac model indicated that A-GAs can be liberated from phospholipid complexes, which were further hydrolyzed by intestinal lipase to generate free gallic acid (GA). Both A-GAs and GA are able to cross the membrane, and the hydrolysis rate of A-GAs and the transport rate of GA are positively correlated with the alkyl chain length. Especially, compared with the corresponding physical mixtures, the phospholipid complexes exhibit slower sustained-release of A-GAs and GA. Therefore, the formation of phospholipid complexes is an effective approach to prolong the residence time in vivo and additionally enhance the bioactivities of A-GAs and GA. More importantly, through regulating the carbon skeleton lengths, controlled-release of alkyl gallates and gallic acid from phospholipid complexes will be achieved.

Formulation and Characterization of Phytosomes as Drug Delivery System of Formononetin: An Effective Anti-Osteoporotic Agent

BACKGROUND

Formononetin (FNT), a methoxy isoflavone, is a potential phytoconstituent utilized for refurbishing fractures in bone tissue. Conceding to its involvement in first-pass metabolism followed by glucuronidation, its absorption efficacy is limited. Hence, it belongs to the BCS class II classification.

OBJECTIVE

We designed the present work to enhance FNT oral bioavailability by using Phospholipids (PL) as a promising carrier. Formononetin Phospholipid Complex (FNT-PC) was prepared by the solvent evaporation method and characterized.

METHODS

FNT-PC was prepared by solvent evaporation method and characterization (FNT-PC) was performed using aqueous/n-octanol solubility and partition coefficient, FTIR, NMR, SEM, and in vivo pharmacokinetic study in female SD rats at 50 mg/kg.

RESULTS

Physicochemical properties like aqueous/n-octanol solubility and partition coefficient were enhanced in FNT-PC. The FTIR spectrum confirmed there was no involvement of functional groups in the preparation of FNT-PC. Whereas, the NMR study resulted in the attachment of carbon (C-8) position of FNT by replacing the quaternary amine of PL to form FNT-PC. When scrutinized for its surface morphology, the FNT-PC exhibited the amorphous geometry that remarkably enhanced the dissolution of FNT (p<0.05) from its pure form. This dissolution effect was also affirmed by the per-oral administration of FNT-PC in female Sprague Dawley (SD) rats at 50 mg/kg dose. The pharmacokinetic profile showed the free FNT levels were markedly increased, correspondingly decreasing the conjugated FNT levels in rat plasma.

CONCLUSION

To summarize, FNT-PC could substantially reduce the first-pass metabolism with enhanced free concentration, improving oral bioavailability for therapeutic use.

Berberine-phospholipid nanoaggregate-embedded thiolated chitosan hydrogel for aphthous stomatitis treatment

Aim: This study aimed to develop nanoaggregates of berberine-phospholipid complex incorporated into thiolated chitosan (TCS) hydrogel for the treatment of aphthous stomatitis. Methods: The berberine-phospholipid complex was formulated through the solvent evaporation technique and assembled into nanoaggregates. TCS was synthesized through the attachment of thioglycolic acid to chitosan (CS). Nanoaggregates-TCS was prepared by the incorporation of nanoaggregates into TCS and underwent in vitro and in vivo tests. Results: Nanoaggregates-TCS exhibited prolonged release of berberine. The mucoadhesive strength of nanoaggregates-TCS increased 1.75-fold compared with CS hydrogel. In vivo studies revealed the superior therapeutic efficacy of nanoaggregates-TCS compared with that of other groups. Conclusion: Due to prolonged drug release, appropriate residence time and anti-inflammatory effects, nanoaggregates-TCS is an effective system for the treatment of aphthous stomatitis.

Phospholipid Complexation for Bioavailability Improvement of Albendazole: Preparation, Characterization and In Vivo Evaluation

The current study aimed to improve the poor solubility of albendazole (ABZ) by means of phospholipid complexation, hence to improve its oral bioavailability. The solvent-evaporation method for ABZ-phospholipid complex (ABZ-PC) preparation was established for the first time. And a systematic optimization of preparation conditions of ABZ-PC was performed. Physicochemical studies of ABZ-PC were performed with FTIR, DSC, and XRD measurements to confirm the formation of the ABZ-PC and reveal the interaction mechanism between ABZ and phospholipid molecules. Solubility determination and morphological characterization were applied to verify the solubility improvement of prepared ABZ-PC. Moreover, the pharmacokinetic performance of ABZ-PC was further evaluated in vivo compared with raw materials of ABZ. Under optimal preparation conditions, the AE of ABZ-PC could be approximately 100%. Physicochemical studies indicated that the P = O group in the phospholipid molecule would interact with the N-H group in the ABZ molecule through hydrogen bonds and ABZ was dispersed in an amorphous state after being prepared into ABZ-PC. The aqueous solubility of ABZ-PC in deionized water (pH7.0) improved by 30-folds than free ABZ, and the AUC_0-t of ABZ-PC was significantly increased by 2.32 times in comparison with raw materials of ABZ through oral administration. The current study developed an effective method for the phospholipid complexation of ABZ. With significantly improved solubility in an aqueous environment, the prepared ABZ-PC exhibited improved oral bioavailability and pharmacokinetic characteristics indicating it could be potentially applied in the oral drug delivery of ABZ.

Preparation, Characterization, and In Vivo Evaluation of Gentiopicroside-Phospholipid Complex (GTP-PC) and Its Self-Nanoemulsion Drug Delivery System (GTP-PC-SNEDDS)

The objective of the present study was to develop a gentiopicroside-phospholipid complex (GTP-PC) and its self-nanoemulsion drug delivery system (GTP-PC-SNEDDS) to increase the oral bioavailability of gentiopicroside (GTP). The factors affecting the formation of GTP-PC were studied with the complexation efficiency and dissociation rate. The properties of the complex were investigated by means of differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), dissolution, etc. Then, GTP-PC was loaded into SNEDDS by investigating the effects of weight ratios of GTP-PC to blank SNEDDS, preparation technology, dilution media, and dilution multi, based on the screening results of oils, surfactants, and cosurfactants. In rats, GTP, GTP-PC, and GTP-PC-SNEDDS were orally administered at different times, and GTP concentrations were determined using RP-HPLC. The optimal GTP-PC was prepared with tetrahydrofuran as the reaction solvent, GTP:phospholipid = 1:2, and stirring for 4 h. The optimal prescription for GTP-PC-SNEDDS was as follows: Maisin 35-1:Miglycol = 30%, Labrasol:Cremophor EL = 1:4 = 40%, Transcutol P = 30%; Maisin 35-1:Miglycol = 12, and the ratio of GTP-PC to blank was 1:10-then the mixture was stirred at 37 °C for 1 d and then placed for 2 d to form stable GTP-PC-SNEDDS. After oral administration of GTP, GTP-PC and GTP-PC-SNEDDS, and mean plasma GTP concentration-time curves were all in accordance with the single-compartment model. The C_max, AUC_0-∞, and Fr of the three formulations were significantly higher than that of GTP, demonstrating that GTP was metabolized rapidly, and its higher bioavailability could be achieved by the formation of GTP-PC and GTP-PC-SNEDDS. Among the three formations, the bioavailability of GTP-PC-SNEDDS was highest, with approximately 2.6-fold and 1.3-fold of Fr value, compared with GTP-PC (suspension) and GTP-PC (oil solution), respectively. Compared with GTP, GTP-PC and GTP-PC-SNEDDS enhanced the bioavailability of GTP significantly. In the future, this study could serve as a reference for clinical trials using GTP-PC and GTP-PC-SNEDDS.

Chrysin-phospholipid complex-based solid dispersion for improved anti-aging and neuroprotective effects in mice

The present study aimed to improve the neuroprotective effect of chrysin (CHR) by combining two formulation techniques, phospholipid (PL) complexation and solid dispersion (SD). CHR-phospholipid complex (CHR-PLC) was prepared through solvent evaporation. The molar ratio CHR/PL (1:3), which exhibited the highest complexation efficiency, was selected for the preparation of CHR-PLC loaded SD (CHR-PLC-SD) with 2-hydroxypropyl β cyclodextrin (2-HPβCD) and polyvinylpyrrolidone 8000. CHR-PLC/2-HPβCD (1:2, w/w) displayed the highest aqueous solubility of CHR (5.86 times more than that of plain CHR). CHR-SD was also prepared using 2-HPβCD for comparison. The in vitro dissolution of CHR-PLC-SD4 revealed an enhancement in the dissolution rate over CHR-PLC (1:3), CHR-SD, and plain CHR by six times. The optimum formulations and plain CHR were evaluated for their neuroprotective effect on brain aging induced by D-galactose in mice. The results demonstrated a behavioral activity elevation, an increase of AMPK, LKB1, and PGC1α brain contents as well as a reduction of AGEs, GFAP, NT-3, TNF-α, and NF-κβ brain contents when compared with those of the D-galactose control group. Thus, the developed formulations stimulated neurogenesis and mitochondrial biogenesis as well as suppressed neuroinflammation and neurodegeneration. The order of activity was as follows: CHR-PLC-SD4 > CHR-PLC (1:3) > CHR-SD > plain CHR.

Solvent Free Twin Screw Processed Silybin Nanophytophospholipid: In Silico, In Vitro and In Vivo Insights

Silybin (SIL) is a polyphenolic phytoconstituent that is commonly used to treat liver disorders. It is difficult to fabricate an orally delivered SIL product due to its low oral bioavailability (0.95%). Therefore, the current research focusses on the development of a novel composition of a phospholipid complex, termed as nanophytophospholipid, of SIL by employing a unique, solvent-free Twin Screw Process (TSP), with the goal of augmenting the solubility and bioavailability of SIL. The optimised SIL-nanophytophospholipid (H6-SNP) was subjected to physicochemical interactions by spectrometry, thermal, X-ray and electron microscopy. The mechanism of drug and phospholipid interaction was confirmed by molecular docking and dynamics studies. Saturation solubility, in vitro dissolution, ex vivo permeation and preclinical pharmacokinetic studies were also conducted. H6-SNP showed good complexation efficiency, with a high practical yield (80%). The low particle size (334.7 ± 3.0 nm) and positively charged zeta potential (30.21 ± 0.3 mV) indicated the immediate dispersive nature of H6-SNP into nanometric dimensions, with good physical stability. Further high solubility and high drug release from the H6-SNP was also observed. The superiority of the H6-SNP was demonstrated in the ex vivo and preclinical pharmacokinetic studies, displaying enhanced apparent permeability (2.45-fold) and enhanced bioavailability (1.28-fold). Overall, these findings indicate that not only can phospholipid complexes be formed using solvent-free TSP, but also that nanophytophospholipids can be formed by using a specific quantity of lipid, drug, surfactant, superdisintegrant and diluent. This amalgamation of technology and unique composition can improve the oral bioavailability of poorly soluble and permeable phytoconstituents or drugs.

Preparation of an isorhamnetin phospholipid complex for improving solubility and anti-hyperuricemia activity

To improve the solubility and anti-hyperuricemia activity of the insoluble natural flavonoid isorhamnetin (ISO), an isorhamnetin phospholipid complex (ISO-PC) was prepared. ISO-PC was prepared through solvent evaporation and its prescription process was optimized. The formation of ISO-PC was verified via multiple characterization methods. Parameters such as drug loading, solubility, octanol-water partition coefficient, stability, and in vivo anti-hyperuricemia activity of ISO-PC were investigated. The complexation efficiency of ISO-PC was 95.1% ± 0.56%. The characterization results confirmed that ISO-PC was bound by intermolecular interactions between ISO and phospholipids. Compared to ISO, the solubility of ISO-PC in water and 1-octanol increased by 122 and 16.5 times, respectively. Additionally, the octanol-water partition coefficient decreased to 1.08. Pharmacodynamic studies have reported that ISO-PC has a more significant effect on reducing serum uric acid levels and renal protection. In conclusion, the findings of this study suggested that ISO-PC could be used as a promising formulation to improve the solubility and the anti-hyperuricemia activity of ISO.

Baicalein self-microemulsion based on drug-phospholipid complex for the alleviation of cytokine storm

Cytokine storm is a phenomenon whereby the overreaction of the human immune system leads to the release of inflammatory cytokines, which can lead to multiple organ dysfunction syndrome. At present, the existing drugs for the treatment of cytokine storm have limited efficacy and severe adverse effects. Here, we report a lymphatic targeting self-microemulsifying drug delivery system containing baicalein to effectively inhibit cytokine storm. Baicalein self-microemulsion with phospholipid complex as an intermediate carrier (BAPC-SME) prepared in this study could be spontaneously emulsified to form 12-nm oil-in-water nanoemulsion after administration. And then BAPC-SME underwent uptake by enterocyte through endocytosis mediated by lipid valve and clathrin, and had obvious characteristics of mesenteric lymph node targeting distribution. Oral administration of BAPC-SME could significantly inhibit the increase in plasma levels of 14 cytokines: TNF-α, IL-6, IFN-γ, MCP-1, IL-17A, IL-27, IL-1α, GM-CSF, MIG, IFN-β, IL-12, MIP-3α, IL-23, and RANTES in mice experiencing systemic cytokine storm. BAPC-SME could also significantly improve the pathological injury and inflammatory cell infiltration of lung tissue in mice experiencing local cytokine storm. This study does not only provide a new lymphatic targeted drug delivery strategy for the treatment of cytokine storm but also has great practical significance for the clinical development of baicalein self-microemulsion therapies for cytokine storm.

Comparative Study of Preparation, Evaluation, and Pharmacokinetics in Beagle Dogs of Curcumin β-Cyclodextrin Inclusion Complex, Curcumin Solid Dispersion, and Curcumin Phospholipid Complex

Curcumin is a natural acidic polyphenol extracted from turmeric with a wide range of biological and pharmacological effects. However, the application of curcumin for animal production and human life is limited by a low oral bioavailability. In this study, natural curcumin was prepared for the curcumin β-cyclodextrin inclusion complex (CUR-β-CD), curcumin solid dispersion (CUR-PEG-6000), and curcumin phospholipid complex (CUR-HSPC) using co-precipitation, melting, and solvent methods, respectively. Curcumin complex formations were monitored using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) techniques via the shifts in the microscopic structure, molecular structure, and crystalline state. Subsequently, twenty-four female beagle dogs were randomly divided into four groups to receive unmodified curcumin and three other curcumin preparations. The validated UPLC-MS assay was successfully applied to pharmacokinetic and bioavailability studies of curcumin in beagle dog plasma, which were collected after dosing at 0 min (predose), 5 min, 15 min, 30 min, 40 min, 50 min, 1.5 h, 3 h, 4.5 h, 5.5 h, 6 h, 6.5 h, 9 h, and 24 h. The relative bioavailabilities of CUR-β-CD, CUR-PEG-6000, and CUR-HSPC were 231.94%, 272.37%, and 196.42%, respectively. This confirmed that CUR-β-CD, CUR-HSPC, and especially CUR-PEG-6000 could effectively improve the bioavailability of curcumin.

Pellets of phospholipids and D-glucose with improved intestinal absorption and oral bioavailability of salvianolic acid B

Salvianolic acid B (SAB) is a widely used cardioprotective agent, while its clinical application was limited by poor intestinal absorption and low oral bioavailability. In this study, SAB phospholipid complex (SP) was first prepared to improve the lipophicity of SAB and then combined with D-glucose to further enhance intestinal absorption. Compared with free SAB, SP or the mixture of SAB and D-glucose, combination of SP and D-glucose showed higher intestinal absorption evidenced by increased effective permeation coefficient (P_eff) in the in situ single-pass intestinal perfusion (SPIP) assay. Subsequently, SP and D-glucose at mass ratio of 1:6, with the highest P_eff of SAB, were chosen for the preparation of complexed pellets to improve oral absorption efficiency of SAB. As expected, the obtained pellets significantly enhanced oral bioavailability of SAB in the pharmacokinetic study characterized by increasing C_max and AUC_0-t of SAB by 14.88-fold and 5.02-fold than free SAB, respectively. In conclusion, combination of D-glucose in SP pellets can effectively improve the intestinal absorption and oral bioavailability of SAB.

Ternary System of Bacogenins with Fulvic Acid and Hydrogenated Soy Lecithin: Preparation, Characterization and, In-Vivo Studies

AIM

The aim of this study was to simultaneously enhance the solubility and stability of bacogenins by a ternary system comprised of hydrogenated soy lecithin and a third auxiliary substance, fulvic acid.

METHOD

Both ternary and binary complexes were prepared using the solvent evaporation method and prepared binary and ternary systems were characterized by Fourier transform infrared technique, differential scanning calorimeter and scanning electron microscope. The entrapment efficacy in both binary and ternary system was calculated and the effect on the solubility, dissolution and stability of bacogenins (hydrolyzed bacoside rich extract) in 40% ethanol was found out. Furthermore, the prepared formulations were subjected to behavioural pharmacological studies.

RESULTS

FTIR, DSC, and SEM studies in totality confirmed the formation of binary and ternary complexes. Enhancement in solubility was observed, and the order of releasecharacteristics was found to be BHFS> BHSL>BHF> BH when the dissolution studies were carried out in 40% aqueous solution of ethanol. A significant improvement in the memory and antioxidant capacity was noticed in both binary, ternary complexes and fulvic acid treatment groups.

CONCLUSION

The results revealed that the ternary complex could be a promising drug delivery system to improve the oral bioavailability of the bacogenins.

Transdermal delivery of triptolide-phospholipid complex to treat rheumatoid arthritis

The aim of this study was to develop and evaluate a triptolide phospholipid complex (TPCX) for the treatment of rheumatoid arthritis (RA) by transdermal delivery. TPCX was prepared and characterized by differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR) analysis, transmission electron microscope (TEM), and scanning electron microscope (SEM). The solubility of TPCX was determined. Then, a TPCX cream was prepared to evaluate its percutaneous permeability and the antiarthritis effect. The transdermal permeability was determined using the Franz method, and a microdialysis system was used for skin pharmacokinetic study. A rat model of RA was prepared to evaluate the pharmacological effects. TPCX increased the solubility of triptolide in water, and the percutaneous permeability of TPCX cream was greatly enhanced compared with triptolide cream. The skin pharmacokinetic study indicated that TPCX cream has a longer biological half-life (t_1/2) and mean residence time (MRT), but it has a shorter T_max than that of triptolide cream in vivo. The area under the curve (AUC_0–t)/AUC_0–∞) and the peak concentration (C_max) of TPCX cream were obviously higher than those of triptolide cream. The TPCX-loaded cream alleviated paw swelling and slowed down the progression of arthritis by inhibiting the inflammatory response by down regulating the TNF-α, IL-1β, and IL-6 levels, thus exhibiting excellent antiarthritic effects. In summary, the prepared TPCX effectively increases the hydrophilicity of triptolide, which is good for its percutaneous absorption and enhances its effect on RA rats. TPCX can be a good candidate for the transdermal delivery to treat RA.

Dual Strategy for Improving the Oral Bioavailability of Resveratrol: Enhancing Water Solubility and Inhibiting Glucuronidation

Resveratrol (RES) suffers from poor water solubility and extensive metabolism, which lead to low bioavailability. A phospholipid complex (PC) containing RES and a UDP-glucuronosyltransferase (UGT) inhibitor was prepared to address these two limiting factors, thereby improving RES bioavailability. First, 11 natural active ingredients metabolized by similar enzyme subtypes to RES were screened in a glucuronidation assay in liver microsomes. Then, glycyrrhetinic acid (GA), the strongest inhibitor, was prepared with RES in a PC. RES-PC was prepared as a control. As expected, the water solubility and the cumulative dissolution of RES were significantly enhanced by RES-PC and RES/GA-PC. Compared with the RES group, the AUC_0-10 of RES and resveratrol-3-glucuronide (R-3-G) in the RES/GA-PC group showed increases of 2.49- and 1.70-fold, respectively, with the proportion of RES absorption to total absorption increasing 1.45 times. These results demonstrated that RES/GA-PC could improve the bioavailability of RES by increasing its water solubility and inhibiting its glucuronidation.

Combination of Phospholipid Complex and Matrix Dispersion

Phospholipid complexation, despite being a successful, versatile, and burgeoning strategy, stickiness of phospholipids leads to suboptimal dissolution rate of drugs. This work was undertaken to fabricate simvastatin-phospholipid complex (SIM-PLC)-loaded matrix dispersion (SIM-PLC-MD) using Soluplus® as carrier material, to augment dispersibility and dissolution of SIM-PLC without altering complexation between simvastatin (SIM) and phospholipid. SIM-PLC and SIM-PLC-MD were prepared using solvent evaporation and discontinuous solvent evaporation techniques, respectively. The successful complexation was substantiated by FTIR method. Besides, PXRD and SEM studies disclosed the absence of crystallinity of SIM in both SIM-PLC and SIM-PLC-MD. The TEM analysis monitored the self-assembly of SIM-PLC and SIM-PLC-MD into colloidal structures, which could be correlated with redispersion in GIT fluids upon oral administration. The considerable increase in hydrophilicity of SIM-PLC-MD and SIM-PLC as evident from partition coefficient experiment can further be correlated with their remarkably improved solubility profiles in the following pattern: SIM-PLC-MD˃SIM-PLC˃SIM. Correspondingly, improved dispersibility of SIM-PLC-MD in comparison to SIM-PLC can be accountable for accelerated dissolution rate by 2.53-fold and 1.5-fold in pH 1.2 and 6.8 conditions, respectively. The oral pharmacokinetic evaluation in Sprague Dawley (SD) rats revealed 3.19-fold enhancement in oral bioavailability of SIM through SIM-PLC-MD when compared with plain SIM, whereas 1.83-fold increment was observed in the case of SIM-PLC. Finally, the efficacy experimentation in SD rats revealed that SIM-PLC-MD significantly reduced triglycerides and cholesterol levels in comparison to SIM and SIM-PLC. These outcomes suggest that a matrix dispersion strategy improves oral bioavailability and hypolipidemic activity of SIM.

Development and evaluation of puerarin-loaded controlled release nanostructured lipid carries by central composite design

The present work was aimed at developing optimized puerarin-loaded nanostructured lipid carrier (PA-NLC) on base of phospholipid complex. The puerarin phospholipid complex (PA-PC) was prepared by a solvent evaporation method and the formulation was confirmed according to the encapsulation efficiency (EE%). The hepatoprotective effect of PA-NLC on BRL 3A cell stimulated by ethanol was carried out using MTT assay, and cell imaging was done using an inverted phase contrast tissue culture microscope. The NLCs were produced by nanoemulsion method using glyceryl monostearate (GMS), olive oil, and Poloxamer 188 as the solid, liquid lipids, and surfactant. A single factor analysis determined the optimal ratio of solid lipid to liquid lipid. A three-factor, five-level central composite design (CCD) was used to predict response variables and construct 3D-response contour plots. The independent variables, which were the concentrations of PA-PC, total lipid, and surfactant affected particle size, surface charge of the nanoparticles, and the EE. An optimized NLC composition consisted of 31.25% PA-PC, 46.87% GMS, 9.38% olive oil, and 18.75% Poloxamer 188. The NLC had an average particle size of 159 ± 1.1 nm, zeta potential of -28.3 mV, EE% of 92.16%, and drug loading (DL%) of 5.75%. Differential scanning calorimetry (DSC), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) studies showed that the formation of NLC was accompanied by changes in crystallinity and intermolecular interaction. The PA-NLC system showed an enhanced therapeutic effect on alcohol-induced cell injury of BRL-3A.

Self-Assembled Lecithin/Chitosan Nanoparticles Based on Phospholipid Complex: A Feasible Strategy to Improve Entrapment Efficiency and Transdermal Delivery of Poorly Lipophilic Drug

PURPOSE

Lecithin/chitosan nanoparticles have shown great promise in the transdermal delivery of therapeutic agents. Baicalein, a natural bioactive flavonoid, possesses multiple biological activities against dermatosis. However, its topical application is limited due to its inherently poor hydrophilicity and lipophilicity. In this study, the baicalein-phospholipid complex was prepared to enhance the lipophilicity of baicalein and then lecithin/chitosan nanoparticles loaded with the baicalein-phospholipid complex were developed to improve the transdermal retention and permeability of baicalein.

METHODS

Lecithin/chitosan nanoparticles were prepared by the solvent-injection method and characterized in terms of particle size distribution, zeta potential, and morphology. The in vitro release, the ex vivo and in vivo permeation studies, and safety evaluation of lecithin/chitosan nanoparticles were performed to evaluate the effectiveness in enhancing transdermal retention and permeability of baicalein.

RESULTS

The lecithin/chitosan nanoparticles obtained by the self-assembled interaction of chitosan and lecithin not only efficiently encapsulated the drug with high entrapment efficiency (84.5%) but also provided sustained release of baicalein without initial burst release. Importantly, analysis of the permeation profile ex vivo and in vivo demonstrated that lecithin/chitosan nanoparticles prolonged the retention of baicalein in the skin and efficiently penetrated the barrier of stratum corneum without displaying skin irritation.

CONCLUSION

These results indicate the potential of drug-phospholipid complexes in enhancing the entrapment efficiency and self-assembled lecithin/chitosan nanoparticles based on phospholipid complexes in the design of a rational transdermal delivery platform to improve the efficiency of transdermal therapy by enhancing its percutaneous retention and penetration in the skin.

Development and Evaluation of Docetaxel-Phospholipid Complex Loaded Self-Microemulsifying Drug Delivery System: Optimization and In Vitro/Ex Vivo Studies

Docetaxel (DTX) has clinical efficacy in the treatment of breast cancer, but it is difficult to develop a product for oral administration, due to low solubility and permeability. This study focused on preparing a self-microemulsifying drug delivery system (SME) loaded with DTX-phospholipid complex (DTX@PLC), to improve the dissolution and gastrointestinal (GI) permeability of DTX. A dual technique combining the phospholipid complexation and SME formulation described as improving upon the disadvantages of DTX has been proposed. We hypothesized that the complexation of DTX with phospholipids can improve the lipophilicity of DTX, thereby increasing the affinity of the drug to the cell lipid membrane, and simultaneously improving permeability through the GI barrier. Meanwhile, DTX@PLC-loaded SME (DTX@PLC-SME) increases the dissolution and surface area of DTX by forming a microemulsion in the intestinal fluid, providing sufficient opportunity for the drug to contact the GI membrane. First, we prepared DTX@PLC-SME by combining dual technologies, which are advantages for oral absorption. Next, we optimized DTX@PLC-SME with nanosized droplets (117.1 nm), low precipitation (8.9%), and high solubility (33.0 mg/g), which formed a homogeneous microemulsion in the aqueous phase. Dissolution and cellular uptake studies demonstrated that DTX@PLC-SME showed 5.6-fold higher dissolution and 2.3-fold higher DTX uptake in Caco-2 cells than raw material. In addition, an ex vivo gut sac study confirmed that DTX@PLC-SME improved GI permeability of DTX by 2.6-fold compared to raw material. These results suggested that DTX@PLC-SME can significantly overcome the disadvantages of anticancer agents, such as low solubility and permeability.

A matrix dispersion based on phospholipid complex system: preparation, lymphatic transport, and pharmacokinetics

Raloxifene hydrochloride (RH) suffers from low oral bioavailability due to its low water-solubility and first-pass metabolism. Therefore, a novel phospholipid complex of RH (RHPC) and a matrix dispersion based on phospholipid complex (RHPC-MD) were successfully prepared and optimized. Several methods were used to validate the formation of RHPC and RHPC-MD, such as differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, infrared spectroscopy, particle size, and zeta potential, meanwhile, their octanol-water partition coefficient, solubility, and dissolution in vitro were also evaluated. To investigate the absorption mechanism of RHPC in vivo, the RHPC was administered to the chylomicron flow blockage rat model. Interestingly, as we expected, a significant reduction in RHPC absorption (67%) (**p< .01) in presence of cycloheximide (CXI) inhibitor was observed, thus confirming the RHPC could be absorbed by lymphatic transport in vivo. Pharmacokinetic studies revealed that the relative oral bioavailability of RHPC as well as RHPC-MD was 223% and 329%, respectively, when comparing with the commercial RH tablets. These outcomes suggested that the current study provided an attractive formulation to enhance the oral bioavailability of RH and stimulated to further research the absorption mechanism of RHPC in vivo.

Preparation of ursolic acid-phospholipid complex by solvent-assisted grinding method to improve dissolution and oral bioavailability

To improve the aqueous solubility and the oral bioavailability of a poorly water-soluble biologically active pentacyclic triterpenoid, ursolic acid (UA), ursolic acid-phospholipid complex (UA-PC) was prepared using solvent-assisted grinding method which is green and simple. The phospholipid complex was characterized by differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), scanning electron microscope (SEM), and transmission electron microscope (TEM), which confirmed the formation of the phospholipid complex. Specifically, compared with free UA, the formulation demonstrated over 276-fold higher aqueous solubility of UA and exhibited faster dissolution rate and higher cumulative dissolution percentages. Finally, the oral bioavailability of the prepared UA-PC was evaluated using Sprague-Dawley (SD) rats. Compared with free UA, the UA-PC exhibited considerable enhancement in the bioavailability with an increase in Cmax (183.80 vs 68.26 μg/l) and AUC 0-24 h (878.0 vs 212.1 μg·h/l), which was consistent with the in vitro results. This enhancement was attributed to the improvement of solubility and dissolution in vitro. Therefore, the method of solvent-assisted grinding appears to be an efficient approach for the preparation of UA-PC, and the prepared UA-PC showed a promising potential to overcome the limitation of poor oral bioavailability associated with low water solubility.

Oral absorption and lymphatic transport of baicalein following drug-phospholipid complex incorporation in self-microemulsifying drug delivery systems

PURPOSE

The aims of this study were to prepare a baicalein self-microemulsion with baicalein-phospholipid complex as the intermediate (BAPC-SMEDDS) and to compare its effects with those of conventional baicalein self-microemulsion (CBA-SMEDDS) on baicalein oral absorption and lymphatic transport.

METHODS

Two SMEDDS were characterized by emulsifying efficiency, droplet size, zeta potential, cloud point, dilution stability, physical stability, and in vitro release and lipolysis. Different formulations of 40 mg/kg baicalein were orally administered to Sprague-Dawley rats to investigate their respective bioavailabilities. The chylomicron flow blocking rat model was used to evaluate their lymphatic transport.

RESULTS

The droplet sizes of BAPC-SMEDDS and CBA-SMEDDS after 100x dilution were 9.6±0.2 nm and 11.3±0.4 nm, respectively. In vivo experiments indicated that the relative bioavailability of CBA-SMEDDS and BAPC-SMEDDS was 342.5% and 448.7% compared to that of free baicalein (BA). The AUC0-t and Cmax of BAPC-SMEDDS were 1.31 and 1.87 times higher than those of CBA-SMEDDS, respectively. The lymphatic transport study revealed that 81.2% of orally absorbed BA entered the circulation directly through the portal vein, whereas approximately 18.8% was transported into the blood via lymphatic transport. CBA-SMEDDS and BAPC-SMEDDS increased the lymphatic transport ratio of BA from 18.8% to 56.2% and 70.2%, respectively. Therefore, self-microemulsion not only significantly improves oral bioavailability of baicalein, but also increases the proportion lymphatically transported. This is beneficial to the direct interaction of baicalein with relevant immune cells in the lymphatic system and for proper display of its effects.

CONCLUSION

This study demonstrates the oral absorption and lymphatic transport characteristics of free baicalein and baicalein SMEDDS with different compositions. This is of great significance to studies on lymphatic targeted delivery of natural immunomodulatory compounds.

Preparation and preliminary pharmacokinetics study of GNA-loaded zein nanoparticles

OBJECTIVES

Gambogenic acid (GNA), one of the main active ingredients isolated from Garcinia cambogia, has shown diverse antitumour activities. However, short biological half-life and low oral bioavailability severely limit its clinical application. Here, we developed GNA-loaded zein nanoparticles (GNA-ZN-NPs) based on phospholipid complex and zein nanoparticles to prolong the circulation time and enhance oral bioavailability of GNA.

METHODS

The physicochemical properties of GNA-ZN-NP were characterized in details. The in vitro release profile, in vivo pharmacokinetic experiments and tissue distribution of GNA-ZN-NPs were also evaluated.

KEY FINDINGS

The particle size, PDI and encapsulation efficiency of GNA-ZN-NPs were 102.90 nm, 0.027 and 76.35 ± 0.64%, respectively. The results of SEM, FTIR, DSC and XRD demonstrated that GNA-ZN-NPs were prepared successfully. The in vitro dissolution of GNA-ZN-NPs exhibited controlled release compared with raw GNA solution. The pharmacokinetic study showed that the AUC of GNA-ZN-NPs was significantly increased, and the t_1/2 and MRT values of GNA-ZN-NPs were 3.21-fold and 2.19-fold higher than that of GNA solution. Tissue distribution results illustrated that GNA-ZN-NPs showed hepatic-targeting properties.

CONCLUSION

GNA-ZN-NPs significantly enhanced the oral bioavailability and prolonged half-life of GNA, providing a promising oral drug delivery system to improve in vivo pharmacokinetic behaviour of GNA.

Enhanced bioavailability and hepatoprotectivity of optimized ursolic acid-phospholipid complex

OBJECTIVE

To prepare and characterize an optimized phospholipid complex of Ursolic acid (UA) to overcome the poor pharmacokinetic properties and to investigate the impact of the complex on hepatoprotective activity and bioavailability in animal model.

SIGNIFICANCE

UA is a potential phytoconstituent obtained from several plant sources, which has been explored for its diverse pharmacological activities including hepatoprotection. Its major limitation is poor absorption, rapid elimination, and hence low bioavailability after administration.

METHODS

Response surface methodology was adopted to formulate an optimized (UA) complex. The complex was characterized by differential thermal analysis (DTA), Fourier transform-Infrared Spectroscopy, Powder X ray Diffraction, molecular docking, etc. The physico-chemical profile (solubility, oil/water partition coefficient) and in vitro dissolution profile was estimated. The formulation was then used to study hepatoprotective activity and bioavailability in animal models.

RESULTS

Results showed that the phospholipid complex of UA has enhanced the hepatoprotective potential as compared to pure UA at the same dose level. The complex restored the levels of serum hepatic marker enzymes with respect to untreated group and increased the relative bioavailability of UA in rat plasma by 8.49-fold in comparison with pure compound at the same dose level. It enhanced the elimination half-life (t1/2 el) from 0.69 ± 1.76 to 8.28 ± 1.98 h.

CONCLUSION

Complexation of UA with phospholipid markedly enhanced the hepatoprotective potential of UA by improving its bioavailability and pharmacokinetic parameters. Novelty statement The present article deals with rational optimization of the formulation parameters for phospholipid complex of ursolic acid by Response Surface Methodology analysis, characterizing the formulation by in silico approach apart from conventional instrumental techniques, and evaluating the in vitro dissolution, pharmacokinetics, and hepatoprotective activity of the complex in animals. Novelty statement The present article deals with rational optimization of the formulation parameters for phospholipid complex of ursolic acid by Response Surface Methodology analysis, characterizing the formulation by in silico approach apart from conventional instrumental techniques, and evaluating the in vitro dissolution, pharmacokinetics, and hepatoprotective activity of the complex in animals.

Phospholipid complex based nanoemulsion system for oral insulin delivery: preparation, in vitro, and in vivo evaluations

Purpose: The aim of this research was to develop a phospholipid complex based nanoemulsion system for oral insulin delivery.

Methods: Insulin-phospholipid complex (IPC) was firstly prepared by an anhydrous co-solvent lyophilization method, and then encapsulated into the oil phase of nanoemulsion to obtain the IPC-based nanoemulsion (IPC-NE). Both water-in-oil (W/O) IPC-NE and oil-in-water (O/W) IPC-NE were formulated and evaluated for comparison.

Results: The obtained W/O IPC-NE and O/W IPC-NE were both spherical in shape with a mean particle size of 18.6±0.79 nm and 27.3±1.25 nm, respectively. While both IPC-NEs exhibited enhanced Caco-2 cell monolayers permeability than IPC and insulin solution, W/O IPC-NE showed relatively greater protective effects against enzymatic degradation than O/W IPC-NE. Moreover, oral administration of W/O IPC-NE exhibited significant hypoglycemic effects, with 12.4-fold and 1.5-fold higher oral bioavailability compared with insulin solution and O/W IPC-NE, respectively.

Conclusion: IPC-NEs, especially the W/O IPC-NE showed promising efficiency in vitro and in vivo, thus could be a potential strategy for oral insulin delivery.

Investigating the Phospholipid Effect on the Bioaccessibility of Rosmarinic Acid-Phospholipid Complex through a Dynamic Gastrointestinal in Vitro Model

Phyto-phospholipid complexes have been developed as a common way of improving the oral bioavailability of poorly absorbable phyto-pharmaceuticals; however, the complexation with phospholipids can induce positive or negative effects on the bioaccessibility of such plant-derived active ingredients in different parts of the gastrointestinal tract (GIT). The purpose of this study was to investigate the effects of phospholipid complexation on the bioaccessibility of a rosmarinic acid-phospholipid complex (RA-PLC) using the TNO dynamic intestinal model-1 (TIM-1). Preparation of RA-PLC was confirmed using X-ray diffraction, Fourier-transform infrared spectroscopy, partition coefficient measurement, and Caco-2 monolayer permeation test. Bioaccessibility parameters in different GIT compartments were investigated. Complexation by phospholipids reduced the bioaccessibility of RA in jejunum compartment, while maintaining the ileum bioaccessibility. The overall bioaccessibility of RA-PLC was lower than the unformulated drug, suggesting that the improved oral absorption from a previous animal study could be considered as a net result of decreased bioaccessibility overwhelmed by enhanced intestinal permeability. This study provides insights into the effects of phospholipid on the bioaccessibility of hydrophilic compounds, and analyzes them based on the relationship between bioaccessibility, membrane permeability, and bioavailability. Additionally, TIM-1 shows promise in the evaluation of dosage forms containing materials with complicated effects on bioaccessibility.

Novel Self-Assembled Ibrutinib-Phospholipid Complex for Potently Peroral Delivery of Poorly Soluble Drugs with pH-Dependent Solubility

As an irreversible small-molecule kinase inhibitor, ibrutinib (IBR) exhibits excellent tumor suppression in various tumor cells. However, IBR is insoluble at neutral pH and can dissolve only at low pH: thus, commercial IBR products present poor bioavailability and weakened in vivo antitumor activity. Therefore, we aimed to develop a stable IBR-phospholipid complex (IBR-PC) using egg phosphatidylglycerol (EPG) as excipients to improve the bioavailability of IBR and further enhance its antitumor effects. IBR-PC was characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), X-ray powder diffraction (XPRD), and molecular docking and simulation test, which all explained the interactions of two components. Solubility tests demonstrate that the novel formulation can maintain excellent solubility (above 5 mg/mL) at various pH levels. Storage stability tests show that no change in particle size or content of IBR-PC was observed during the experimental period. In vivo pharmacokinetic results demonstrated that the relative bioavailability of IBR-PC was a 9.14-fold improvement relative to that of IBR suspension (IBR-susp). Furthermore, IBR-PC was associated with enhanced cytotoxic activity in vitro and superior tumor growth suppression in vivo compared to that resulting from the free IBR. Thus, the proposed IBR-PC system is a promising drug delivery system that enhances the oral bioavailability of IBR, resulting in its improved in vivo antitumor effect.

Preparation and Evaluation of Probucol-Phospholipid Complex with Enhanced Bioavailability and No Food Effect

To enhance the oral bioavailability and eliminate the food effect of probucol. Probucol-phospholipid complex was prepared using solvent-evaporation method in this research. Several methods were used to validate the formation of complexes, such as FT-IR, SEM, DSC and PXRD, and the solubility of PRO and PRO-PLC was detected by HPLC. Pharmacokinetic testing was conducted in the fasted and fed state. FTIR, SEM, DSC and PXRD validated the existence of PRO-PLC. The solubility of PRO in complexes was 15.05 μg/mL, which was 215-fold of the PRO-API. The dissolution rate was increased by preparing PRO-PLC. Compared with commercial tablets, the PRO-PLC complexes exhibited higher peak plasma concentration (1.69 ± 0.44 μg/mL), increased AUC_0-24 h (6.8 ± 1.3 μg/mL h), which mean the bioavailability of PRO was increased. In addition, the absorption of PRO was not interfered with food. In conclusion, an improved solubility and bioavailability was achieved with the preparation of PRO-PLC. Additionally, the dissolution behaviour was good and the food effect was eliminated.

A novel matrix dispersion based on phospholipid complex for improving oral bioavailability of baicalein: preparation, in vitro and in vivo evaluations

Phospholipid complex is one of the most successful approaches for enhancing oral bioavailability of poorly absorbed plant constituents. But the sticky property of phospholipids results in an unsatisfactory dissolution of drugs. In this study, a matrix dispersion of baicalein based on phospholipid complex (BaPC-MD) was first prepared by a discontinuous solvent evaporation method, in which polyvinylpyrrolidone-K30 (PVP-K30) was employed for improving the dispersibility of baicalein phospholipid complex (BaPC) and increasing dissolution of baicalein. The combination ratio of baicalein and phospholipids in BaPC-MD was 99.39% and baicalein was still in a complete complex state with phospholipid in BaPC-MD. Differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier Transform Infrared (FTIR) analyzes demonstrated that baicalein was fully transformed to an amorphous state in BaPC-MD and phospholipid complex formed. The water-solubility and n-octanol solubility of baicalein in BaPC-MD significantly increased compared with those of pure baicalein. Compared with baicalein and BaPC, the cumulative dissolution of BaPC-MD at 120 min increased 2.77- and 1.23-fold, respectively. In vitro permeability study in Caco-2 cells indicated that the permeability of BaPC-MD was remarkably higher than those of baicalein and BaPC. Pharmacokinetic study showed that the average C_max of BaPC-MD was significantly increased compared to baicalein and BaPC. AUC_0–14 h of BaPC-MD was 5.01- and 1.91-fold of baicalein and BaPC, respectively. The novel BaPC-MD significantly enhanced the oral bioavailability of baicalein by improving the dissolution and permeability of baicalein without destroying the complexation state of baicalein and phospholipids. The current drug delivery system provided an optimal strategy to significantly enhance oral bioavailability for poorly water-soluble drugs.

Application of Soluplus to Improve the Flowability and Dissolution of Baicalein Phospholipid Complex

In this study, a novel ternary complex system (TCS) composed of baicalein, phospholipids, and Soluplus was prepared to improve the flowability and dissolution for baicalein phospholipid complex (BPC). TCS was characterized using differential scanning calorimetry (DSC), infrared spectroscopy (IR), powder X-ray diffraction (PXRD), and scanning electron microscopy (SEM). The flowability, solubility, oil–water partition coefficient, in vitro dissolution, and in vivo pharmacokinetics of the system were also evaluated. DSC, IR, PXRD, and SEM data confirmed that the crystal form of baicalein disappeared in BPC and TCS. Furthermore, the angle of repose of TCS of 35° indicated an improvement in flowability, and solubility increased by approximately eight-fold in distilled water when TCS was compared with BPC (41.00 ± 4.89 μg/mL vs. 5.00 ± 0.16 μg/mL). Approximately 91.24% of TCS was released at the end of 60 min in 0.5% SDS (pH = 6.8), which suggested that TCS could improve the dissolution velocity and extent. Moreover, TCS exhibited a considerable enhancement in bioavailability with higher peak plasma concentration (25.55 μg/mL vs. 6.05 μg/mL) and increased AUC_0–∞ (62.47 μg·h/mL vs. 50.48 μg·h/mL) with 123.75% relative bioavailability compared with BPC. Thus, Soluplus achieved the purpose of improving the flowability and solubility of baicalein phospholipid complexes. The application of Soluplus to phospholipid complexes has great potential.

Sustained Anti-inflammatory Effect of Resveratrol-Phospholipid Complex Embedded Polymeric Patch

Resveratrol-phospholipid complex (Phytosome®) (RSVP) was found better aqueous soluble and permeable than free resveratrol (RSV). RSVPs were incorporated in polymeric patch prepared by solvent casting method using Eudragit RL 100, PVP K30, and PEG 400 for application on dermal sites for sustained treating of inflammation. Prepared patches were evaluated for various physicochemical properties, surface morphology by SEM, TEM, and compatibility of patch components by FT-IR and DSC studies. Optimized formulation (F9) gave 95.79 ± 3.02% drug release and 51.36% (4.28 ± 0.48 mg/cm²) skin permeation after 24 h. Skin extract when examined for drug accumulation showed 38.31 ± 2.42% drug content. FE-SEM images of the patch taken after drug release and skin permeation studies showed that RSVPs in polymeric patch are stable and retain their structure after 24 h long exposure to physiologic environment. Sustained anti-inflammatory effect was established in carrageenan-induced paw edema model in which test formulation gave 84.10% inhibition of inflammation at 24 h as compared to 39.58% for standard diclofenac sodium gel. The CLSM study confirmed the localization of RSVPs for a longer period, thus enabling drug targeting to the dermis for sustained effect. Skin irritation test on rabbit revealed that the patches are safe for skin application. Histological observations suggested that after exposure to the permeants, the SC integrity had not altered and no evidence of presence of inflammatory cells found. RSVP (Phytosome®) containing patches abled to give sustained therapeutic effect that may be useful in treating acute and chronic inflammation.

Improved oral bioavailability of 20(R)-25-methoxyl-dammarane-3β, 12β, 20-triol using nanoemulsion based on phospholipid complex: design, characterization, and in vivo pharmacokinetics in rats

The aim of the study was to improve the oral absorption of the compound 25-OCH3-PPD with poor hydrophilicity and lipophilicity. 25-OCH3-PPD-phospholipid complex was prepared by solvent evaporation, then characterized by differential scanning calorimetry, scanning electron microscopy, and infrared absorption spectroscopy. The aqueous solubility and oil-water partition coefficient were compared with the free compound. A nanoemulsion loaded with 25-OCH3-PPD-phospholipid complex was developed by dissolving the complex in water in the presence of hydrophilic surfactant under sonication. After oral administration of the nanoemulsion and the suspension of 25-OCH3-PPD in rats, the concentrations of 25-OCH3-PPD in plasma were determined by high-performance liquid chromatography-tandem mass spectrometry method. The results showed that the solubility of the complex in water and n-octanol was enhanced. The oil-water partition coefficient improved 1.7 times. Peak plasma concentration and area under the curve(0-24 h) of the nanoemulsion of 25-OCH3-PPD-phospholipid complex were higher than that of free compound by 3.9- and 3.5-folds.

20(S)-Protopanaxadiol Phospholipid Complex: Process Optimization, Characterization, In Vitro Dissolution and Molecular Docking Studies

20(S)-Protopanaxadiol (PPD), a bioactive compound extracted from ginseng, possesses cardioprotective, neuroprotective, anti-inflammatory, antiestrogenic, anticancer and anxiolytic effects. However, the clinical application of PPD is limited by its weak aqueous solubility. In this study, we optimized an efficient method of preparing its phospholipid complex (PPD-PLC) using a central composite design and response surface analysis. The prepared PPD-PLC was characterized by differential scanning calorimetric, powder X-ray diffraction, Fourier-transformed infrared spectroscopy and nuclear magnetic resonance analyses associated with molecular docking calculation. The equilibrium solubility of PPD-PLC in water and n-octanol increased 6.53- and 1.53-times, respectively. Afterwards, using PPD-PLC as the intermediate, the PPD-PLC-loaded dry suspension (PPD-PLC-SU) was prepared with our previous method. In vitro evaluations were conducted on PPD-PLC and PPD-PLC-SU, including dissolution behaviors and stability properties under different conditions. Results of in vitro dissolution behavior revealed the improved dissolution extents and rates of PPD-PLC and PPD-PLC-SU (p < 0.05). Results of the formulation stability investigation also exposed the better stability of PPD-PLC-SU compared with free PPD. Therefore, phospholipid complex technology is a useful formulation strategy for BCS II drugs, as it could effectively improve their hydrophilicity and lipophilicity.

Preparation and evaluation of a self-nanoemulsifying drug delivery system loaded with Akebia saponin D-phospholipid complex

BACKGROUND

Akebia saponin D (ASD) exerts various pharmacological activities but with poor oral bioavailability. In this study, a self-nanoemulsifying drug delivery system (SNEDDS) based on the drug-phospholipid complex technique was developed to improve the oral absorption of ASD.

METHODS

ASD-phospholipid complex (APC) was prepared using a solvent-evaporation method and characterized by infrared spectroscopy, differential scanning calorimetry, morphology observation, and solubility test. Oil and cosurfactant were selected according to their ability to dissolve APC, while surfactant was chosen based on its emulsification efficiency in SNEDDS. Pseudoternary phase diagrams were constructed to determine the optimized APC-SNEDDS formulation, which was characterized by droplet size determination, zeta potential determination, and morphology observation. Robustness to dilution and thermodynamic stability of optimized formulation were also evaluated. Subsequently, pharmacokinetic parameters and oral bioavailability of ASD, APC, and APC-SNEDDS were investigated in rats.

RESULTS

The liposolubility significantly increased 11.4-fold after formation of APC, which was verified by the solubility test in n-octanol. Peceol (Glyceryl monooleate [type 40]), Cremophor^® EL (Polyoxyl 35 castor oil), and Transcutol HP (Diethylene glycol monoethyl ether) were selected as oil, surfactant, and cosurfactant, respectively. The optimal formulation was composed of Glyceryl monooleate (type 40), Polyoxyl 35 castor oil, Diethylene glycol monoethyl ether, and APC (1:4.5:4.5:1.74, w/w/w/w), which showed a particle size of 148.0±2.7 nm and a zeta potential of -13.7±0.92 mV after dilution with distilled water at a ratio of 1:100 (w/w) and good colloidal stability. Pharmacokinetic studies showed that APC-SNEDDS exhibited a significantly greater C_max1 (733.4±203.8 ng/mL) than ASD (437.2±174.2 ng/mL), and a greater C_max2 (985.8±366.6 ng/mL) than ASD (180.5±75.1 ng/mL) and APC (549.7±113.5 ng/mL). Compared with ASD, T_max1 and T_max2 were both remarkably shortened by APC-SNEDDS. The oral bioavailability in rats was enhanced significantly to 183.8% and 431.8% by APC and APC-SNEDDS, respectively.

CONCLUSION

These results indicated that APC-SNEDDS was a promising drug delivery system to enhance the oral bioavailability of ASD.

Anti-inflammatory potential of a lipid-based formulation of a rotenoid-rich fraction prepared from Boerhavia diffusa

CONTEXT

Boerhavia diffusa L. (Nyctaginaceae) roots are used in Ayurveda for treating inflammatory diseases. Generally poor oral bioavailability is a major problem associated with herbal drugs.

OBJECTIVE

To develop a phospholipid complex of rotenoid-rich fraction (RRF) and evaluate its in vivo anti-inflammatory activity and pharmacokinetic study.

MATERIALS AND METHODS

RRF was prepared from a 70% ethanol extract of B. diffusa roots. This RRF was complexed with phosphatidylcholine by refluxing in 70% ethanol. In vivo anti-inflammatory activity of RRF-PC and RRF was determined using the carrageenan-induced rat paw edema method, at a dose equivalent to 100 mg/kg p.o. of RRF. Edema volume was calculated at 3 and 5 h. The plasma concentration of boeravinone B was estimated in rats at a same dose level. Blood samples were collected at 1, 2, 4, 6, 8, 10, 12, 24, and 36 h.

RESULTS

(1)H and (31)P NMR spectra of RRF-PC showed up-field shift of protons of the (+)N(CH3)3 group (3.37 → 3.23) and the phosphorus atom (-1.26 → -1.57 ppm), respectively, which confirmed phospholipid complex formation between phosphatidylcholine [PO4 and (+)N(CH3)3 groups] and phytoconstituents by hydrogen bonding. The RRF-PC showed significantly enhanced in vivo anti-inflammatory activity (64%) as compared with RRF (48%) and ibuprofen (50%) at 5 h (p < 0.001). Furthermore, detected plasma concentration of boeravinone B was two times higher in RRF-PC (75 ng/mL) as compared with RRF (40 ng/mL).

CONCLUSION

The present study demonstrated an increased anti-inflammatory potential and higher plasma level of boeravinone B in lipid-based formulation (RRF-PC) as compared with RRF.

Phospholipid complex as an approach for bioavailability enhancement of echinacoside

CONTEXT

Echinacoside (ECH) has been shown to possess a multitude of pharmacological activities, however, oral administered ECH failed to fulfill its therapeutic potential due to poor absorption and low bioavailability. Thus, there is a pressing need to develop a new oral dosage form to enhance its intestinal absorption and improve bioavailability.

OBJECTIVE

The aim of this study was to formulate ECH into phospholipid complex (phytosome, PHY) to enhance intestinal absorption and oral bioavailability of ECH in vivo.

METHODS

The PHY was prepared by a solvent evaporation method and was characterized by differential scanning calorimetry (DSC) and infrared spectroscopy (IR), and then the physicochemical properties, intestinal absorption and bioavailability of the PHY were investigated.

RESULTS

Compared with the physical mixture (MIX) or ECH alone, the n-octanol/water partition coefficient (P) determination results showed that the lipophilicity of ECH was significantly enhanced by formation of PHY. Accordingly, the intestinal absorption rate (Ka) was improved to 2.82-fold and the effective permeability coefficient (Peff) increased to 3.39-fold. The concentrations of ECH in rat plasma at different times after oral administration of PHY were determined by HPLC. Pharmacokinetic parameters of the PHY in rats were Tmax = 1.500 h, Cmax = 3.170 mg/mL, AUC0-∞ = 9.375 mg/L h and AUC0-24 = 7.712 mg/L h, respectively.

CONCLUSIONS

Compared with ECH alone or the MIX group, the relative bioavailability of ECH was increased significantly after formulation into PHY (p < 0.05). This might be mainly due to an improvement of the absorption of PHY.

Mechanism of enhanced oral absorption of morin by phospholipid complex based self-nanoemulsifying drug delivery system

Phospholipid complex (PLC) based self-nanoemulsifying drug delivery system (PLC-SNEDDS) has been developed for efficient delivery of drugs with poor solubility and low permeability. In the present study, a BCS class IV drug and a P-glycoprotein (P-gp) substrate, morin, was selected as the model drug to elucidate the oral absorption mechanism of PLC-SNEDDS. PLC-SNEDDS was superior to PLC in protecting morin from degradation by intestinal enzymes in vitro. In situ perfusion study showed increased intestinal permeability by PLC was duodenum-specific. In contrast, PLC-SNEDDS increased morin permeability in all intestinal segments and induced a change in the main absorption site of morin from colon to ileum. Moreover, ileum conducted the lymphatic transport of PLC-SNEDDS, which was proven by microscopic intestinal visualization of Nile red labeled PLC-SNEDDS and lymph fluids in vivo. Low cytotoxicity and increased Caco-2 cell uptake suggested a safe and efficient delivery of PLC-SNEDDS. The increased membrane fluidity and disrupted actin filaments were closely associated with the increased cell uptake of PLC-SNEDDS. PLC-SNEDDS could be internalized into enterocytes as an intact form in a cholesterol-dependent manner via clathrin-mediated endocytosis and macropinocytosis. The enhanced oral absorption of morin was attributed to the P-gp inhibition by Cremophor RH and the intact internalization of M-PLC-SNEDDS into Caco-2 cells bypassing P-gp recognition. Our findings thus provide new insights into the development of novel nanoemulsions for poorly absorbed drugs.

Thymopentin nanoparticles engineered with high loading efficiency, improved pharmacokinetic properties, and enhanced immunostimulating effect using soybean phospholipid and PHBHHx polymer

Formulation of protein and peptide drugs with sustained release properties is crucial to enhance their therapeutic effect and minimize administration frequency. In this study, immunomodulating polymeric systems were designed by manufacturing PHBHHx nanoparticles (NPs) containing thymopentin (TP5). The release profile of the drug was studied over a period of 7 days. The PHBHHx NPs containing TP5-phospholipid (PLC) complex (TP5-PLC) displayed a spherical shape with a mean size, zeta potential, and encapsulation efficiency of 238.9 nm, -32.0 mV, and 72.81%, respectively. The cytotoxicity results showed the PHBHHx NPs had a relatively low toxicity in vitro. TP5 entrapped in the NPs could hardly release in vitro, while the NPs had longer than 7 days release duration after a single subcutaneous injection in Wistar rats. The immunodepression rat model was built to evaluate the immunomodulating effects of TP5-PLC-NPs in vivo. The results of T-lymphocyte subsets (CD3(+), CD4(+), CD8(+), and CD4(+)/CD8(+) ratio) analysis and superoxide dismutase (SOD) values suggested that TP5-PLC-NPs had stronger immunoregulation effects than TP5 solution. In conclusion, an applicable approach to markedly enhancing the loading of a water-soluble peptide into a hydrophobic polymer matrix has been introduced. Thus, TP5-PLC-NPs are promising nanomedicine systems for sustained release effects of TP5.

Luteolin-phospholipid complex: preparation, characterization and biological evaluation

OBJECTIVES

This study aims to develop novel carrier system incorporating luteolin, a poorly soluble biologically active plant active.

METHODS

We investigated a lipid-based drug delivery system to enhance dissolution and absorption profile of luteolin. Luteolin was complexed with phospholipids, and the preparation was characterized. The formulation was evaluated for physicochemical properties, in-vitro solubility or release studies. In vivo anti-inflammatory action of luteolin and its phospholipid complex was evaluated by using carrageenan and 12-O-tetradecanoylphorbol-13-acetate as inducers.

KEY FINDINGS

The prepared luteolin-phospholipid complex (LPC) showed drug loading of about 72.64% with average particle size of 152.6 nm. The Fourier transform infrared spectroscopy and thermal studies confirm formation of complex. The solubility of luteolin as LPC was about 2.5 times higher than the solubility of pure luteolin in water. In the diffusion study, LPC showed 95.12% of drug release at the end of 2 h. Animal studies demonstrated significant differences in response of LPC and luteolin.

CONCLUSION

LPC was successfully prepared by optimizing the process parameters. The resultant delivery system improved bioavailability and efficacy of luteolin and in the future may become an efficient tool for administration of luteolin.

Soya phospholipid complex of mangiferin enhances its hepatoprotectivity by improving its bioavailability and pharmacokinetics

BACKGROUND

Mangiferin is a xanthonoid present in Mangifera indica. It has been reported for a variety of pharmacological activities, including hepatoprotection. However, the major disadvantage of mangiferin is its reduced biological activity due to poor absorption, low bioavailability and rapid elimination from the body after administration. The aim of this study was to prepare a phospholipid complex of mangiferin to overcome these limitations and to investigate the impact of the complex on hepatoprotective activity and bioavailability.

RESULTS

The results showed that the complex has an enhanced hepatoprotective and in vivo antioxidant activity as compared to pure mangiferin at the same dose level (30 and 60 mg kg⁻¹). The complex restored the levels of serum hepatic marker enzymes and liver antioxidant enzymes with respect to carbon tetrachloride-treated animals. The complex also increased the bioavailability of mangiferin in rat serum by 9.75-fold compared to pure mangiferin at the same dose level and enhanced the elimination half-life (t(1/2 el)) from 1.71 ± 0.12 h⁻¹ to 3.52 ± 0.27 h⁻¹.

CONCLUSION

The results suggested that the complexation of mangiferin with soya phospholipid enhanced the hepatoprotection and in vivo antioxidant activity, which may be due to the improved bioavailability and pharmacokinetics of mangiferin in rat serum.

Lipid nanoparticles loaded with 7-ethyl-10-hydroxycamptothecin-phospholipid complex: in vitro and in vivo studies

7-Ethyl-10-hydroxy-camptothecin (SN38), the active metabolite of irinotecan (CPT-11), is an effective antineoplastic agent against many malignancies. Although it is 100-fold to 1000-fold more potent than CPT-11, the clinical utility of SN38 has been extremely restricted because of its poor solubility in any pharmaceutically acceptable solvents. The aim of this study was to develop SN38 nanoparticles (SN38-PC-LNs) using pharmaceutically acceptable excipients, and investigate the therapeutic efficacies in vitro and in vivo. SN38-phospholipid complex (SN38-PC) was prepared and loaded into lipid nanoparticles. The particle size was approximately 200 nm with a narrow size distribution. A high encapsulation efficiency of 88.11% ± 1.41% and drug loading of 9.55% ± 0.84% were achieved under the optimal condition. SN38-PC-LNs exhibited potent cytotoxic effects against a panel of human tumor cell lines (HT-29, HepG2, A549 and MCF-7). In vivo evaluation proved the enhanced antitumor efficacy of SN38-PC-LNs in mice bearing S180 tumor as well. The results from this study demonstrated an effective formulation of SN38 has been developed, which is promising for the delivery of SN38 for tumor chemotherapy.

Preparation and characterization of tetrandrine-phospholipid complex loaded lipid nanocapsules as potential oral carriers

Background

Tetrandrine is an active constituent that is extracted from the root tuber of the Chinese herb Stephania tetrandra S. Moore. It has shown various pharmacological effects, such as antitumor activity, multidrug resistance reversal, and hepatic fibrosis resistance. In clinical applications, it has been used to treat hypertension, pneumosilicosis, and lung cancer. However, the poor water solubility of tetrandrine has limited its application. In this study, a newly emerging oral drug carrier of phospholipid complex loaded lipid nanocapsules was developed to improve the oral bioavailability of tetrandrine.

Methods

The phospholipid complex was prepared with the solvent-evaporation method to enhance the liposolubility of tetrandrine. The formation of the phospholipid complex was confirmed with a solubility study, infrared spectroscopy, and a differential scanning calorimetry (DSC) analysis. The tetrandrine-phospholipid complex loaded lipid nanocapsules (TPC-LNCs) were prepared using the phase inversion method. Lyophilization was performed with mannitol (10%) as a cryoprotectant. TPC-LNCs were characterized according to their particle size, zeta potential, encapsulation efficiency, morphology by transmission electron microscopy, and crystallinity by DSC. In addition, the in vitro release of tetrandrine from TPC-LNCs was examined to potentially illustrate the in vivo release behavior. The in vivo bioavailability of TPC-LNCs was studied and compared to tetrandrine tablets in rats.

Results

The liposolubility of tetrandrine in n-octanol improved from 8.34 μg/mL to 35.64 μg/mL in the tetrandrine-phospholipid complex. The prepared TPC-LNCs were spherical-shaped particles with a small size of 40 nm and a high encapsulation efficiency of 93.9%. DSC measurements revealed that the crystalline state was less ordered in lipid nanocapsules. The in vitro release study demonstrated a fast release of approximately 25% in the first 1 hour, which was followed by a sustained release of 70% over 12 hours. The relative bioavailability of TPC-LNCs compared to that of tablets was 208%, indicating a significant improvement in the oral absorption of tetrandrine.

Conclusion

The TPC-LNCs system developed in this study is a promising carrier that improves the oral bioavailability of tetrandrine in rats. The phospholipid complex loaded lipid nanocapsules have great potential for use as an oral drug delivery system for moderately lipophilic drugs that are encapsulated in the lipid nanocapsules.

A novel drug-phospholipid complex enriched with micelles: preparation and evaluation in vitro and in vivo

Mixed micelles are widely used to increase solubility and bioavailability of poorly soluble drugs. One promising antitumor drug candidate is 20(S)-protopanaxadiol (PPD), although its clinical application is limited by low water solubility and poor bioavailability after oral administration. In this study, we developed mixed micelles consisting of PPD-phospholipid complexes and Labrasol(®) and evaluated their potential for oral PPD absorption. Micelles were prepared using a solvent-evaporation method, and their physicochemical properties, including particle size, zeta potential, morphology, crystal type, drug loading, drug entrapment efficiency, and solubility, were characterized. Furthermore, in vitro release was investigated using the dialysis method, and transport and bioavailability of the mixed micelles were investigated through a Caco-2 cell monolayer and in vivo absorption studies performed in rats. Compared with the solubility of free PPD (3 μg/mL), the solubility of PPD in the prepared mixed micelles was 192.41 ± 1.13 μg/mL in water at room temperature. The in vitro release profiles showed a significant difference between the more rapid release of free PPD and the slower and more sustained release of the mixed micelles. At the end of a 4-hour transport study using Caco-2 cells, the apical-to-basolateral apparent permeability coefficients (P(app)) increased from (1.12 ± 0.21) × 10(6) cm/s to (1.78 ± 0.16) × 10(6) cm/s, while the basolateral-to-apical P(app) decreased from (2.42 ± 0.16) × 10(6) cm/s to (2.12 ± 0.32) × 10(6). In this pharmacokinetic study, compared with the bioavailability of free PPD (area under the curve [AUC](0-∞)), the bioavailability of PPD from the micelles (AUC(0-∞)) increased by approximately 216.36%. These results suggest that novel mixed micelles can significantly increase solubility, enhance absorption, and improve bioavailability. Thus, these prepared micelles might be potential carriers for oral PPD delivery in antitumor therapies.

A novel drug-phospholipid complex enriched with micelles: preparation and evaluation in vitro and in vivo

Mixed micelles are widely used to increase solubility and bioavailability of poorly soluble drugs. One promising antitumor drug candidate is 20(S)-protopanaxadiol (PPD), although its clinical application is limited by low water solubility and poor bioavailability after oral administration. In this study, we developed mixed micelles consisting of PPD–phospholipid complexes and Labrasol^® and evaluated their potential for oral PPD absorption. Micelles were prepared using a solvent-evaporation method, and their physicochemical properties, including particle size, zeta potential, morphology, crystal type, drug loading, drug entrapment efficiency, and solubility, were characterized. Furthermore, in vitro release was investigated using the dialysis method, and transport and bioavailability of the mixed micelles were investigated through a Caco-2 cell monolayer and in vivo absorption studies performed in rats. Compared with the solubility of free PPD (3 μg/mL), the solubility of PPD in the prepared mixed micelles was 192.41 ± 1.13 μg/mL in water at room temperature. The in vitro release profiles showed a significant difference between the more rapid release of free PPD and the slower and more sustained release of the mixed micelles. At the end of a 4-hour transport study using Caco-2 cells, the apical-to-basolateral apparent permeability coefficients (P_app) increased from (1.12 ± 0.21) × 10⁶ cm/s to (1.78 ± 0.16) × 10⁶ cm/s, while the basolateral-to-apical P_app decreased from (2.42 ± 0.16) × 10⁶ cm/s to (2.12 ± 0.32) × 10⁶. In this pharmacokinetic study, compared with the bioavailability of free PPD (area under the curve [AUC]_0–∞), the bioavailability of PPD from the micelles (AUC_0–∞) increased by approximately 216.36%. These results suggest that novel mixed micelles can significantly increase solubility, enhance absorption, and improve bioavailability. Thus, these prepared micelles might be potential carriers for oral PPD delivery in antitumor therapies.

Design and evaluation of a novel evodiamine-phospholipid complex for improved oral bioavailability

A novel evodiamine (EVO)-phospholipid complex (EPLC) was designed to improve the bioavailability of EVO. A central composite design approach was employed for process optimization. EPLC were characterized by differential scanning calorimetry, ultraviolet spectroscopy, Fourier transformed infrared spectroscopy, (1)H-NMR spectroscopy, matrix-assisted laser desorption/ionization time-of-flight spectroscopy, apparent solubility, and dissolution rate. After oral administration of EPLC, the concentrations of EVO at different time points were determined by high-performance liquid chromatography. The optimal formulation for EPLC was obtained where the values of X (1), X (2), and X (3) were 2, 0.5, and 2.5 mg/mL, respectively. The average particle size and zeta potential of EPLC with the optimized formulation were 246.1 nm and -26.94 mV, respectively. The EVO and phospholipids in the EPLC were associated with non-covalent interactions. The solubility of EPLC in water and the dissolution rate of EPLC in phosphate-buffered solution (pH 6.8) were substantially enhanced. The plasma EVO concentration-time curves of EPLC and free EVO were both in accordance with the two-compartment model. The peak concentration and AUC(0-∞) of EPLC were increased, and the relative bioavailability was significantly increased to 218.82 % compared with that of EVO.

Preparation, characterization, and in vivo evaluation of a self-nanoemulsifying drug delivery system (SNEDDS) loaded with morin-phospholipid complex

Background

As a poorly water-soluble drug, the oral application of morin is limited by its low oral bioavailability. In this study, a new self-nanoemulsifying drug delivery system (SNEDDS), based on the phospholipid complex technique, was developed to improve the oral bioavailability of morin.

Methods

Morin-phospholipid complex (MPC) was prepared by a solvent evaporation method and characterized by infrared spectroscopy and X-ray diffraction. After formation of MPC, it was found that the liposolubility of morin was significantly increased, as verified through solubility studies. An orthogonal design was employed to screen the blank SNEDDS, using emulsifying rate and particle size as evaluation indices. Ternary phase diagrams were then constructed to investigate the effects of drug loading on the self-emulsifying performance of the optimized blank SNEDDS. Subsequently, in vivo pharmacokinetic parameters of the morin-phospholipid complex self-nanoemulsifying drug delivery system (MPC-SNEDDS) were investigated in Wistar rats (200 mg/kg of morin by oral administration).

Results

The optimum formulation was composed of Labrafil^® M 1944 CS, Cremophor^® RH 40, and Transcutol^® P (3:5:3, w/w), which gave a mean particle size of approximately 140 nm. Oral delivery of the MPC-SNEDDS exhibited a significantly greater C_max (28.60 μg/mL) than the morin suspension (5.53 μg/mL) or MPC suspension (23.74 μg/mL) (all P < 0.05). T_max was prolonged from 0.48 to 0.77 hours and to 1 hour for MPC and MPC-SNEDDS, respectively. In addition, the relative oral bioavailability of morin formulated in the MPC-SNEDDS was 6.23-fold higher than that of the morin suspension, and was significantly higher than that of the MPC suspension (P < 0.05).

Conclusion

The study demonstrated that a SNEDDS combined with the phospholipid complex technique was a promising strategy to enhance the oral bioavailability of morin.

Development and evaluation of pharmacosomes of aceclofenac

Pharmacosomes are amphiphilic lipid vesicular systems containing phospholipid complexes with a potential to improve bioavailability of poorly water soluble as well as poorly lipophilic drugs. To improve the water solubility, bioavailability and minimize the gastrointestinal toxicity of aceclofenac, its pharmacosomes were prepared. Aceclofenac was complexed with phosphatidylcholine (80%) in two different ratios (1:1 and 2:1) using conventional solvent evaporation technique. Pharmacosomes thus prepared were subjected to solubility and drug content evaluation, scanning electron microscopy, differential scanning calorimetry, X ray powder diffraction and in vitro dissolution study. Pharmacosomes of aceclofenac were found to be disc shaped with rough surface in scanning electron microscopy. Drug content was found to be 91.88% (w/w) for aceclofenac phospholipid complex (1:1) and 89.03% (w/w) aceclofenac-phospholipid complex (2:1). Differential scanning calorimetric thermograms and X ray powder diffraction datas confirmed the formation of phospholipid complex. Solubility and dissolution profile of the prepared complex was found to be much better than aceclofenac.

Mixed micelles loaded with silybin-polyene phosphatidylcholine complex improve drug solubility

AIM

To prepare a novel formulation of phosphatidylcholine (PC)-bile salts (BS)-mixed micelles (MMs) loaded with silybin (SLB)-PC complex for parenteral applications.

METHODS

SLB-PC-BS-MMs were prepared using the co-precipitation method. Differential scanning calorimetry (DSC) analysis was used to confirm the formation of the complex and several parameters were optimized to obtain a high quality formulation. The water-solubility, drug loading, particle size, zeta potential, morphology and in vivo properties of the SLB-PC-BS-MMs were determined.

RESULTS

The solubility of SLB in water was increased from 40.83 ± 1.18 μg/mL to 10.14 ± 0.36 mg/mL with a high drug loading (DL) of 14.43% ± 0.44% under optimized conditions. The SLB-PC-BS-MMs were observed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) and showed spherical shapes. The particle size and zeta potential, as measured by photon correlation spectroscopy (PCS), were about 30 ± 4.8 nm and -39 ± 5.0 mV, respectively. In vivo studies showed that incorporation of the SLB-PC complex into PC-BS-MMs led to a prolonged circulation time of the drug.

CONCLUSION

This novel formulation appears to be a good candidate for drug substances that exhibit poor solubility for parenteral administration.

Process optimization, characterization and pharmacokinetic evaluation in rats of ursodeoxycholic acid-phospholipid complex

The purpose of this research was to study whether the bioavailability of ursodeoxycholic acid could be improved by administering ursodeoxycholic acid-phospholipid complex (UDCA-PLC) orally to rats. A central composite design approach was used for process optimization in order to obtain the acceptable UDCA-PLC. The physicochemical properties of the complex obtained by optimal parameters were investigated by means of scanning electron microscopy and X-ray diffraction. The pharmacokinetic parameters and bioavailability studies were conducted in rats of UDCA after oral administration of UDCA-PLC and UDCA tablet. Multiple linear regression analysis for process optimization revealed that the acceptable UDCA-PLC was obtained wherein the optimal values of X(1), X(2) and X(3) were 3, 60 degrees C and 3 h, respectively. The XRD studies of UDCA-PLC obtained by the optimal parameters demonstrated that UDCA and phospholipids in the UDCA-PLC were combined by non-covalent bonds, not form new compounds. But pharmacokinetic parameters of the complex in rats were T(max) 1.6 h, C(max) 0.1346 microg/ml, AUC(0-infinity) 11.437 microg x h/ml, respectively. The relative bioavailability of UDCA of UDCA-PLC was increased by 241%,compared with the reference ursodeoxycholic acid tablet.