Formulation and in vitro and in vivo characterization of a phenytoin self-emulsifying drug delivery system (SEDDS)

Solid Self-Nanoemulsifying Drug Delivery Systems of Furosemide: In Vivo Proof of Concept for Enhanced Predictable Therapeutic Response

Liquid self-nano emulsifying drug delivery systems (SNEDDS) of furosemide (FSM) have been explored as a potential solution for enhancing solubility and permeability but are associated with rapid emulsification, spontaneous drug release, and poor in vivo correlation. To overcome the shortcoming, this study aimed to develop liquid and solid self-emulsifying drug delivery systems for FSM, compare formulation dynamics, continue in vivo therapeutic efficacy, and investigate the advantages of solidification. For this purpose, liquid SNEDDS (L-SEDDS-FSM) were formed using oleic acid as an oil, chremophore EL, Tween 80, Tween 20 as a surfactant, and PEG 400 as a co-surfactant containing 53 mg/mL FSM. At the same time, solid SNEDDS (S-SEDDS-FSM) was developed by adsorbing liquid SNEDDS onto microcrystalline cellulose in a 1:1 ratio. Both formulations were evaluated for size, zeta potential, lipase degradation, and drug release. Moreover, in vivo diuretic studies regarding urine volume were carried out in mice to investigate the therapeutic responses of liquid and solid SNEDDS formulations. After dilution, L-SEDDS-FSM showed a mean droplet size of 115 ± 4.5 nm, while S-SEDDS-FSM depicted 116 ± 2.6 nm and zeta potentials of -5.4 ± 0.55 and -6.22 ± 1.2, respectively. S-SEDDS-FSM showed 1.8-fold reduced degradation by lipase enzymes in comparison to L-SEDDS-FSM. S-SEDDS-FSM demonstrated a sustained drug release pattern, releasing 63% of the drug over 180 min, in contrast to L-SEDDS-FSM, exhibiting 90% spontaneous drug release within 30 min. L-SEDDS-FSM exhibited a rapid upsurge in urine output (1550 ± 56 μL) compared to S-SEDDS-FSM, showing gradual urine output (969 ± 29 μL) till the 4th h of the study, providing sustained urine output yet a predictable therapeutic response. The solidification of SNEDDS effectively addresses challenges associated with spontaneous drug release and precipitation observed in liquid SNEDDS, highlighting the potential benefits of solid SNEDDS in improving the therapeutic response of furosemide.

Enhancing oral bioavailability of Ca-DTPA by self double emulsifying drug delivery system (SDEDDS)

OBJECTIVE

BCS class III drug (highly soluble, poorly permeable) possesses low oral bioavailability. The research work highlights the utility of self-double emulsifying drug delivery system (SDEDDS) which are stable isotropic mixture of w/o primary emulsion and hydrophilic surfactants for improving oral bioavailability of Ca-DTPA (Calcium diethylenetriamine pentaacetate). Upon oral administration, SDEDDS rapidly emulsifies into w/o/w double emulsions in the aqueous gastrointestinal environment, with hydrophilic drugs entrapped inside oil reservoirs.

METHODS

SDEDDS formulation was successfully developed using excipients, that is, medium chain triglycerides, oleic acid, phospholipids, Span 80, Tween 80 using double emulsification technique.

RESULTS

The optimized formulation F4 (Aq. phase: 11.6%w,w; MCT & oleic acid: 70.9%w/w; Span 80:17.5%w/w; Lecithin:16%w/w and Tween 80 (10%w/w)) appeared bright yellow liquid which upon dilution appeared milky white within 2 min, droplet size (501.7 nm), pdi value (0.044), zeta potential (-52 mV), entrapment efficiency (79.6 ± 1.63), viscosity (72.2 ± 1.8 mpA.s), significant high cumulative in vitro drug permeation (CDP) and 2.17-fold increase in apparent permeability coefficient. Pharmacokinetic studies in rats showed 1.17-fold increases in AUC of F4 and comparatively higher plasma levels (Cmax) compared with pure drug administered orally. The Absolute (OF4, OD) and Relative bioavailability was found to be 14.52%, 12.35%, and 117.47%, respectively.

CONCLUSION

The present studies have clearly demonstrated that SDEDDS could readily form w/o/w double emulsions in vivo with enhanced in vitro and in vivo oral bioavailability. Therefore, considerable augmentation in the rate and extent of oral drug absorption ratified the better performance of the SDEDDS in enhancing the bioavailability of Ca-DTPA.

Drug permeation enhancement, efficacy, and safety assessment of azelaic acid loaded SNEDDS hydrogel to overcome the treatment barriers of atopic dermatitis

Atopic dermatitis is one of the most widespread chronic inflammatory skin conditions that can occur at any age, though the prevalence is highest in children. The purpose of the current study was to prepare and optimize the azelaic acid (AzA) loaded SNEDDS using Pseudo ternary phase diagram, which was subsequently incorporated into the Carbopol 940 hydrogel for the treatment of atopic dermatitis. The composition was evaluated for size, entrapment efficiency, in vitro, ex vivo, and in vivo studies. The polydispersity index of the optimized preparation was found to be less than 0.5, and the size of the distributed globules was found to be 151.20 ± 3.67 nm. The SNEDDS hydrogel was characterized for pH, viscosity, spreadability, and texture analysis. When compared to the marketed formulation, SNEDDS hydrogel was found to have a higher rate of permeation through the rat skin. In addition, a skin irritation test carried out on experimental animals showed that the SNEDDS formulation did not exhibit any erythematous symptoms after a 24-h exposure. In conclusion, the topical delivery of AzA through the skin using SNEDDS hydrogel could prove to be an effective approach for the treatment of atopic dermatitis.

Development of Dapagliflozin Solid Lipid Nanoparticles as a Novel Carrier for Oral Delivery: Statistical Design, Optimization, In-Vitro and In-Vivo Characterization, and Evaluation

Controlling hyperglycemia and avoiding glucose reabsorption are significant goals in type 2 diabetes treatments. Among the numerous modes of medication administration, the oral route is the most common. Introduction: Dapagliflozin is an oral hypoglycemic agent and a powerful, competitive, reversible, highly selective, and orally active human SGLT2 inhibitor. Dapagliflozin-loaded solid lipid nanoparticles (SLNs) are the focus of our present investigation. Controlled-release lipid nanocarriers were formulated by integrating them into lipid nanocarriers. The nanoparticle size and lipid utilized for formulation help to regulate the release of pharmaceuticals over some time. Dapagliflozin-loaded nanoparticles were formulated by hot homogenization followed by ultra-sonication. The morphology and physicochemical properties of dapagliflozin-SLNs have been characterized using various techniques. The optimized dapagliflozin-SLNs have a particle size ranging from 100.13 ± 7.2 to 399.08 ± 2.4 nm with 68.26 ± 0.2 to 94.46 ± 0.7% entrapment efficiency (%EE). Dapagliflozin-SLNs were optimized using a three-factor, three-level Box–Behnken design (BBD). Polymer concentration (X1), surfactant concentration (X2), and stirring duration (X3) were chosen as independent factors, whereas %EE, cumulative drug release (%CDR), and particle size were selected as dependent variables. Interactions between drug substances and polymers were studied using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Differential scanning calorimetry (DSC), X-ray diffraction (XRD), and atomic force microscopy (AFM) analysis indicated the crystalline change from the drug to the amorphous crystal. Electron microscope studies revealed that the SLNs’ structure is nearly perfectly round. It is evident from the findings that dapagliflozin-SLNs could lower elevated blood glucose levels to normal in STZ-induced diabetic rats, demonstrating a better hypoglycemic impact on type 2 diabetic patients. The in vivo pharmacokinetic parameters of SLNs exhibited a significant rise in C_max (1258.37 ± 1.21 mcg/mL), AUC (5247.04 mcg/mL), and oral absorption (2-fold) of the drug compared to the marketed formulation in the Sprague Dawley rats.

Preparation and characterization of a hydroxypropyl methylcellulose based wafer for simultaneous delivery of phenytoin and insulin as wound dressing material

In this study, a novel wafer based on Hydroxypropyl methylcellulose (HPMC) was prepared as a wound dressing for the simultaneous delivery of phenytoin (PT) and insulin; evaluation of the cutaneous wound repair property was performed too. Due to its low water solubility, PT was encapsulated in polymeric micelles (PM) by the film hydration method at different polymer/drug ratios and characterized in terms of particle size (PS), polydispersity index (PdI), zeta potential (ZP), drug loading (DL) %, entrapment efficiency (EE) %, and drug release. Then, the optimized PT loaded PM (PT-PM) was embedded in the wafers prepared from the HPMC polymer, alone or in combination with Carbopol 940 (CB) and xanthan gum (XG). This wafer also contained a fixed amount of insulin (PT-PM-Insulin-wafer). The obtained wafers were evaluated in terms of morphology, water uptake ability, porosity, bioadhesion and hardness features. Finally, the efficacy of the PT-PM-Insulin-wafer was assessed in full-thickness excision wound models. The optimized PT-PM showed the PS of 84.05 ± 1.80 nm, PdI of 0.28 ± 0.22, ZP of -3.38 ± 0.26 mV, DL of 15.63 ± 0.01%, EE of 92.66 ± 0.08%, and the release efficiency of 59.95 ± 0.03%. The results obtained from the XRD studies of PT-PM also demonstrated the transition of the crystalline nature of the PT to the amorphous form, while FTIR studies showed some intermolecular interaction of PT and the Soluplus® copolymer chain. It was also found that the incorporation of XG into HPMC wafers influenced the microstructure, thus increasing the porosity, water uptake ability and bioadhesion. Compared with other groups, the PT-PM-Insulin-wafer group showed the enhancement of wound closure through increasing collagen deposition and re-epithelialization. The present study, therefore, revealed that the PT-PM-Insulin-wafer group might have very promising applications for wound healing.

Enhancement of the Solubility and Bioavailability of Pitavastatin through a Self-Nanoemulsifying Drug Delivery System (SNEDDS)

The purpose of the study was to develop an SNEDDS to improve the solubility and bioavailability of pitavastatin. The solubility of pitavastatin in different oils, surfactants, and co-surfactants was determined and a pseudo-ternary phase diagram was constructed. The SNEDDS was characterized by zeta-sizer, zeta-potential, FTIR, DSC, and TGA. Release and permeation of pitavastatin from the SNEDDS was studied for 12 and 24 h, respectively. The lipolysis test, RBC lysis, effect on lipid profile, and pharmacokinetics were studied. The SPC3 formulation showed a 104 ± 1.50 nm particle size, a 0.198 polydispersity index (PDI), and a –29 zeta potential. FTIR, DSC, and TGA showed the chemical compatibility and thermal stability. The release and permeation of pitavastatin from SPC3 was 88.5 ± 2.5% and 96%, respectively. In the lipolysis test, the digestion of SPC3 yielded a high amount of pitavastatin and showed little RBC lysis. The lipid profile suggested that after 35 days of administration of the SNEDDS, there was a marked decrease in TC, LDL, and triglyceride levels. The SNEDDS of SPC3 showed an 86% viability of Caco-2 cells. Pharmacokinetics of SPC3 showed improved values of C_max, T_max, half-life, MRT, AUC, and AUMC compared to the reference formulation. Our study demonstrated that the SNEDDS effectively enhanced the solubility and bioavailability of a BCS class II drug.

Polymeric versus lipid nanocapsules for miconazole nitrate enhanced topical delivery: in vitro and ex vivo evaluation

Nanocapsules can be equated to other nanovesicular systems in which a drug is entrapped in a void containing liquid core surrounded by a coat. The objective of the present study was to investigate the potential of polymeric and lipid nanocapsules (LNCs) as innovative carrier systems for miconazole nitrate (MN) topical delivery. Polymeric nanocapsules and LNCs were prepared using emulsification/nanoprecipitation technique where the effect of poly(ε-caprolactone (PCL) and lipid matrix concentrations with respect to MN were assessed. The resulted nanocapsules were examined for their average particle size, zeta potential, %EE, and in vitro drug release. Optimum formulation in both polymeric and lipidic nanocapsules was further subjected to anti-fungal activity and ex vivo permeation tests. Based on the previous results, nanoencapsulation strategy into polymeric and LNCs created formulations of MN with slow biphasic release, high %EE, and improved stability, representing a good approach for the delivery of MN. PNCs were best fitted to Higuchi’s diffusion while LNCs followed Baker and Lonsdale model in release kinetics. The encapsulated MN either in PNCs or LNCs showed higher cell viability in WISH amniotic cells in comparison with free MN. PNCs showed less ex vivo permeation. PNCs were accompanied by high stability and more amount drug deposition (32.2 ± 3.52 µg/cm²) than LNCs (12.7 ± 1.52 µg/cm²). The antifungal activity of the PNCs was high 19.07 mm compared to 11.4 mm for LNCs. In conclusion, PNCs may have an advantage over LNCs by offering dual action for both superficial and deep fungal infections.

Microemulsions: Unique Properties, Pharmacological Applications, and Targeted Drug Delivery

Microemulsions, comprising oil, water and a surfactant, in association with some co-surfactant, are thermodynamically stable systems. They have found applications in a large number of chemical and pharmacological processes due to their unique properties such as large interfacial area, low interfacial tension, and most importantly, the ability to solubilize and deliver hydrophobic drugs. In addition to the oral and intravenous route, they are suitable for drug delivery through the ophthalmic, vaginal, pulmonary, dental, and topical routes. This review highlights the properties and several recent developments in the use of microemulsions for medical treatment purposes including targeted drug delivery.

Development and optimization of sitagliptin and dapagliflozin loaded oral self-nanoemulsifying formulation against type 2 diabetes mellitus

Control of hyperglycemia and prevention of glucose reabsorption (glucotoxicity) are important objectives in the management of type 2 diabetes. This study deals with an oral combined dosage form design for two anti-diabetic drugs, sitagliptin and dapagliflozin using self-nanoemulsifying drug delivery systems (SNEDDS). The SNEDDS were developed using naturally obtained bioactive medium-chain/long-chain triglycerides oil, mixed glycerides and nonionic surfactants, and droplet size was measured followed by the test for antioxidant activities. Equilibrium solubility and dynamic dispersion experiments were conducted to achieve the maximum drug loading. The in vitro digestion, in vivo bioavailability, and anti-diabetic effects were studied to compare the representative SNEDDS with marketed product Dapazin^®. The representative SNEDDS containing black seed oil showed excellent self-emulsification performance with transparent appearance. Characterization of the SNEDDS showed nanodroplets of around 50–66.57 nm in size (confirmed by TEM analysis), in addition to the high drug loading capacity without causing any precipitation in the gastro-intestinal tract. The SNEDDS provided higher antioxidant activity compared to the pure drugs. The in vivo pharmacokinetic parameters of SNEDDS showed significant increase in C_max (1.99 ± 0.21 µg mL⁻¹), AUC (17.94 ± 1.25 µg mL⁻¹), and oral absorption (2-fold) of dapagliflozin compared to the commercial product in the rat model. The anti-diabetic studies showed the significant inhibition of glucose level in treated diabetic mice by SNEDDS combined dose compared to the single drug therapy. The combined dose of sitagliptin-dapagliflozin using SNEDDS could be a potential oral pharmaceutical product for the improved treatment of type 2 diabetes mellitus.

Effect Of Surfactant Chain Length On Emulsification Dynamics Of Self Emulsifying Formulation Of Poorly Soluble Drug

AIM

In this work the aim was to study the chain length of surfactant on the self emulsifying system of a poorly soluble drug, aceclofenac. The selection of almond oil as a lipid vehicle was done on basis of solubility and compatibility of the vehicle with the drug.

METHODS

The effect of varying chain length of different surfactants of Tween series namely Tween 20, Tween 40, Tween 60 and Tween 80 was evaluated on self emulsifying efficiency by constructing pseudoternary diagrams. PEG-400 was used as co-surfactant in a definite ratio with all the surfactants to minimize their concentration. The best self emulsifying ability was exhibited by Tween 80: PEG-400 combination followed by Tween 60: PEG-400, Tween 40: PEG-400, Tween 20: PEG-400. This observation indicates that as the chain length of Tweens increases their ability to form a good microemulsion increases if same co-surfactant is used.

RESULTS

However it has also been found that the presence of unsaturated bond in Tween 80 provides it an elasticity which supports good intermixing of oil and water and leading to formation of a fine microemulsion. Six different formulations were prepared using combination of almond oil, Tween 80, PEG-400 and the drug aceclofenac.

CONCLUSION

The formulations were subjected to various evaluation parameters such as dispersibility, transmittance, pH, globule size, polydispersibility, zeta potential, viscosity, refractive index and in vitro dissolution. The best formulation was found to have globule size of less than 100 nm, zeta potential of -3.35 ± 0.60 mV which indicates formation of a microemulsion of aceclofenac with good stability.

Nose-to-brain delivery of phenytoin and its hydrophilic prodrug fosphenytoin combined in a microemulsion - formulation development and in vivo pharmacokinetics

Phenytoin is a low aqueous solubility antiepileptic drug, but its phosphate ester prodrug fosphenytoin is soluble, although less permeable. In a previous study, the intranasal administration of aqueous-based formulations of fosphenytoin led to high but delayed phenytoin bioavailability compared to the intravenous route. In this work, we hypothesized that formulating an association of the prodrug fosphenytoin and the drug phenytoin (the active and diffusible form), could result in a faster and/or more effective brain targeting. Hence, nano or microemulsions containing both active drug and prodrug were developed and characterized regarding viscosity, osmolality, pH, mean size and in vitro drug release. Then, in vivo pharmacokinetics of a selected microemulsion containing fosphenytoin and phenytoin was evaluated in mice following intranasal administration and compared with a similar microemulsion containing fosphenytoin only. Both microemulsions led to higher brain drug levels at short time points than previously developed simpler aqueous based fosphenytoin formulations, likely due to the microemulsion's permeation enhancing effect. In addition, having a small amount of phenytoin in the formulation led to an equivalent maximum brain drug concentration and an overall higher absolute bioavailability, with a prolonged drug exposure. Hence, it can be concluded that if there is a need for a fast and prolonged therapeutic effect, a drug/phosphate ester prodrug combination in a microemulsion is ideal, but if a fast effect is all that is needed, having the prodrug alone could be enough, while considering a formulation with permeation enhancing components.

Intranasal fosphenytoin: The promise of phosphate esters in nose-to-brain delivery of poorly soluble drugs

Intranasal administration could increase both safety and efficacy of drugs acting on the central nervous system, but low solubility severely limits administration through this route. Phenytoin's prodrug, fosphenytoin, is hydrophilic and freely soluble in water, but less permeable since it is dianionic. We aimed to assess whether this phosphoester prodrug could be a suitable alternative to phenytoin in intranasal delivery. Secondly, we aimed to compare simple formulation strategies in fosphenytoin delivery. Fosphenytoin formulations containing thermosensitive and/or mucoadhesive (hydroxypropyl methylcellulose, HPMC) polymers were developed, guided by viscosity, gelling temperatures, osmolality, and in vitro drug release tests. Then, a pharmacokinetic study was performed, comparing an intravenous fosphenytoin solution, an intranasal fosphenytoin solution, and intranasal fosphenytoin mucoadhesive formulations with or without albumin. Formulations containing HPMC allowed high drug strengths, and had a relatively fast release profile, which was not changed by albumin. Intranasal administration of a formulation with HPMC and albumin prolonged drug concentration over time and led to complete or even increased absolute bioavailability. Moreover, phenytoin's blood levels did not reach the high peak obtained with intravenous administration. In conclusion, the use of phosphate ester prodrugs could be an efficient and safe strategy to increase the intranasal bioavailability of poorly soluble drugs.

Development, Characterization, and in-vivo Pharmacokinetic Study of Lamotrigine Solid Self-Nanoemulsifying Drug Delivery System

Purpose

This study aimed to prepare solid self-nanoemulsified drug delivery system (S-SNEDDS) of lamotrigine (LMG) for enhancing its dissolution and oral bioavailability (BA).

Methods

Nineteen liquid SNEDDS were prepared (R1-R19) using D-optimal design with different ratios of oil, surfactant (S), and cosurfactant (Cos). The formulations were characterized regarding robustness to dilution, droplet size, thermodynamic stability testing, self-emulsification time, in-vitro release in 0.1 N HCl and phosphate buffer (PB; pH 6.8). Design Expert^® 11 software was used to select the optimum formulations. Eight S-SNEDDS were prepared (S1-S8) using 2³ factorial design, and characterized by differential scanning calorimetry (DSC), powder x-ray diffraction (PXRD), and scanning electron microscopy (SEM). The optimum formulation was chosen regarding in-vitro drug released in 0.1 N HCl and PB, compared to pure LMG and commercial tablet (Lamictal^®). The BA of LMG from the optimized S-SNEDDS formulation was evaluated in rabbits compared to pure LMG and Lamictal^®.

Results

The optimized S-SNEDDS was S2, consisting of R9 adsorbed on Aeroperl^® 300 in a ratio of 1:1, with the best results regarding in-vitro drug released in 0.1 N HCl at 15 min (100%) compared to pure LMG (73.40%) and Lamictal^® (79.43%), and in-vitro drug released in PB at 45 min (100%) compared to pure LMG (30.46%) and Lamictal^® (92.08%). DSC, PXRD, and SEM indicated that LMG was molecularly dispersed within the solid nano-system. The BA of S2 was increased 2.03 and 1.605 folds compared to pure LMG, and Lamictal^®, respectively.

Conclusion

S2 is a promising S-SNEDDS formulation. It can be a potential carrier for improving dissolution, and BA of LMG.

In Silico studies of novel Sildenafil self-emulsifying drug delivery system absorption improvement for pulmonary arterial hypertension

Sildenafil is a potent selective inhibitor of phosphosdiesterase-5 previously used in erectile dysfunction and subsequently approved in 2005 for pulmonary arterial hypertension treatment. Since oral administration of sildenafil shows pharmacokinetic problems with mean absolute bioavailability of 41%, the goal of this work was to develop a novel sildenafil self-emulsifying drug delivery system (SEDDS) for oral absorption improvement and management of dosage. One pharmaceutical solution and four SEDDS containing sildenafil were successfully obtained and SEDDS formed O/W nanoemulsion with droplet size less than 300 nm. The stability studies evidenced that the SEDDS containing 3.3% w/w of sildenafil yielded the best results. The safety of 2-pyrrolidone/isobutanol in oral formulations was assessed in mice and no lethality was achieved in the placebo groups with LD50 of 490 mg/Kg for SEDDS II-3.3, suggesting it as a safe excipient for humans. Therewithal, in silico studies using PBPK models provided the pharmacokinetic profile of sildenafil SEDDS. Subsequently, in silico evaluation indicated that the sildenafil SEDDS droplet size influenced its bioavailability, enhancing absorption, assuring a good pharmacokinetic profile. These findings suggest that the formulations developed here presented the potential to enhance drug oral absorption with the possibility to control drug dosage as they are liquid pharmaceutical formulations.

Nanoemulsions and thermosensitive nanoemulgels of phenytoin and fosphenytoin for intranasal administration: Formulation development and in vitro characterization

Phenytoin is a low solubility anticonvulsant drug. It has, nonetheless, other possible therapeutic indications, such as neuropathic pain, including trigeminal neuralgia, or wound healing. Its use has decreased due to side effects, but nasal/intranasal administration could significantly increase drug safety and efficacy. The aim of this work was to develop and study nanoemulsions and thermosensitive nanoemulgels of phenytoin and fosphenytoin, in combination, for intranasal administration, with immediate and sustained release profiles. Nanoemulsions were prepared by adding the aqueous phase, containing gelling polymers in the case of nanoemulgels, to emulsion preconcentrates, followed, in the optimized procedure, by premix membrane emulsification. Formulation design and optimization was guided by drug strength, rheological behavior, osmolality, mean droplet size and polydispersity. Fosphenytoin interfered significantly with Carbopol but not with Pluronic's gelation, and allowed to achieve drug strengths equivalent to 22 or 27 mg/g of phenytoin in lead nanoemulsions, and 16.7 mg/g of phenytoin in the lead nanoemulgel. The final selected low viscosity nanoemulsions had an immediate or prolonged fosphenytoin release profile, depending of anhydrous phase proportion (10% or 40%, respectively). The thermosensitive nanoemulgel, with 10% anhydrous phase, showed prolonged drug release. Future studies will establish whether they are more suited for topical effects or therapeutic brain delivery.

Novel oral dosage regimen based on self-nanoemulsifying drug delivery systems for codelivery of phytochemicals - Curcumin and thymoquinone

Background

Curcumin and Thymoquinone are very well-known phytochemicals for their potent anti-inflammatory and anticancer properties. The major challenges for curcumin is its poor aqueous solubility and erratic oral bioavailability.

Objective

To develop a novel liquid self-nanoemulsifying drug delivery system (SNEDDS) containing curcumin and thymoquinone and further converted into a solid dosage form using adsorbents Syloid® and Neusilin® as the solid carrier.

Methods

The characterization of the liquid and solid SNEDDS was performed by particle size & zeta potential analysis, scanning electron microscopy, differential scanning calorimetry, fourier transform infrared spectroscopy and X-ray powder diffraction. The drug loading, and in vitro release studies were carried out to investigate the efficiency of curcumin release from SNEDDS.

Results

The liquid SNEDDS containing black seed oil showed excellent self-emulsification performance with transparent appearance. The results of characterization studies showed that solidification using 50% (w/w) Syloid® and Neusilin® in the liquid formulation yield free flowing powder with no agglomeration but Neusilin® produced smooth granules than Syloid® and kept the drugs stable in amorphous state. In vitro dissolution studies indicated that liquid SNEDDS formulations of F4 and its solid SNEDDS using Neusilin® provided high dissolution efficiency and reproducibility for curcumin and thymoquinone. However, Neusilin® showed higher rate of dissolution (more than 65%, p < 0.05) compared to Syloid® for curcumin.

Conclusions

Curcumin loaded-SNEDDS formulation containing thymoquinone in liquid & solid dosage forms were successfully developed with an increased drug loading and dissolution rate, which could be the potential combined delivery system for various anti-inflammatory and anti-cancer treatments.

Stabilization benefits of single and multi-layer self-nanoemulsifying pellets: A poorly-water soluble model drug with hydrolytic susceptibility

Solidified self-nanoemulsifying drug delivery systems (SNEDDS) offer strong option to enhance both drug aqueous solubility and stability. The current study was designed to evaluate the potential stabilization benefits of solidifying cinnarizine (CN) liquid SNEDDS into single and multi-layer self-nanoemulsifying pellets (SL-SNEP and ML-SNEP, respectively). The selected formulations were enrolled into accelerated, intermediate and long-term stability studies. The chemical stability was assessed based on the % of intact CN remaining in formulation. The physical stability was assessed by monitoring the in-vitro dissolution and physical appearance of the formulations. The degradation pathway of CN within lipid-based formulation was proposed to involve a hydroxylation reaction of CN molecule. The chemical stability study revealed significant CN degradation in liquid SNEDDS, SL-SNEP and ML-SNEP (lacking moisture-sealing) within all the storage conditions. In contrast, the moisture sealed ML-SNEP showed significant enhancement of CN chemical stability within the formulation. In particular, ML-SNEP coated with Kollicoat Smartseal 30D showed superior CN stabilization and no significant decrease in dissolution efficiency, at all the storage conditions. The observed stability enhancement is owing to the complete isolation between CN and SNEDDS layer as well as the effective moisture protection provided by Kollicoat Smartseal 30D. Hence, the degradation problem could be eradicated completely. The incorporation of silicon dioxide had an important role in the inhibition of pellet agglomeration upon storage. Accordingly, ML-SNEP coated with Kollicoat Smartseal 30D and/or silicon dioxide could be an excellent dosage form that combine dual enhancement of CN solubilization and stabilization.

Multi-Layer Self-Nanoemulsifying Pellets: an Innovative Drug Delivery System for the Poorly Water-Soluble Drug Cinnarizine

Beside their solubility limitations, some poorly water-soluble drugs undergo extensive degradation in aqueous and/or lipid-based formulations. Multi-layer self-nanoemulsifying pellets (ML-SNEP) introduce an innovative delivery system based on isolating the drug from the self-nanoemulsifying layer to enhance drug aqueous solubility and minimize degradation. In the current study, various batches of cinnarizine (CN) ML-SNEP were prepared using fluid bed coating and involved a drug-free self-nanoemulsifying layer, protective layer, drug layer, moisture-sealing layer, and/or an anti-adherent layer. Each layer was optimized based on coating outcomes such as coating recovery and mono-pellets%. The optimized ML-SNEP were characterized using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), in vitro dissolution, and stability studies. The optimized ML-SNEP were free-flowing, well separated with high coating recovery. SEM showed multiple well-defined coating layers. The acidic polyvinylpyrrolidone:CN (4:1) solution presented excellent drug-layering outcomes. DSC and XRD confirmed CN transformation into amorphous state within the drug layer. The isolation between CN and self-nanoemulsifying layer did not adversely affect drug dissolution. CN was able to spontaneously migrate into the micelles arising from the drug-free self-nanoemulsifying layer. ML-SNEP showed superior dissolution compared to Stugeron® tablets at pH 1.2 and 6.8. Particularly, on shifting to pH 6.8, ML-SNEP maintained > 84% CN in solution while Stugeron® tablets showed significant CN precipitation leaving only 7% CN in solution. Furthermore, ML-SNEP (comprising Kollicoat® Smartseal 30D) showed robust stability and maintained > 97% intact CN within the accelerated storage conditions. Accordingly, ML-SNEP offer a novel delivery system that combines both enhanced solubilization and stabilization of unstable poorly soluble drugs.

Self-Nanoemulsified Drug Delivery System of Hydrochlorothiazide for Increasing Dissolution Rate and Diuretic Activity

Hydrochlorothiazide (HCTZ) is a class IV drug according to the Biopharmaceutical Classification System. This study aimed the development of self-nanoemulsifying drug delivery system (SNEDDS) for HCTZ as an approach to overcome the biopharmaceutical limitations. Pre-formulation screening and ternary phase diagrams were carried out to select the oil phase, the surfactant, and the co-surfactant as the amount of each constituent. The optimized formulations, with reduced amount of surfactant, and composed of medium chain triglycerides, Cremophor EL and Transcutol P did not affect the pH or show drug incompatibilities. The SNEDDS were stabilized by the nanoscale globules and high negative zeta potential. All the physicochemical characterization assays were performed in biorelevant media to better predict the in vivo performance. The enhanced dissolution rate of the SNEDDS reflected in the in vivo diuretic activity, presenting a natriuresis, kaliuresis, and chloriuresis at early stages and an increased volume of total urine compared with HCTZ alone. The designed SNEDDS produced an improvement in the pharmacodynamics due to high dissolution and probable inhibition of intestinal efflux protein by Cremophor EL. The use of SNEDDS demonstrated to be an efficient approach to modulate the absorption of HCTZ and drug therapeutics.

Investigation of Need of Natural Bioenhancer for a Metabolism Susceptible Drug-Raloxifene, in a Designed Self-Emulsifying Drug Delivery System

Bioenhancers can increase the bioavailability of metabolism susceptible drugs. The present study was designed to understand the impact of bioenhancer on permeability and bioavailability of a biopharmaceutical drug disposition classification system (BDDCS) class II drug raloxifene (RLX). RLX undergoes extensive first pass metabolism by UGT enzymes in gastrointestinal tract (GIT) and has an oral bioavailability of about 2%. Self-emulsifying drug delivery system (SEDDS) of RLX was developed using a designed approach and this formulation was loaded with reported bioenhancers: quercetin and piperine. These formulations were tested for improvement in permeability and bioavailability of the RLX. The apparent permeability using everted gut sac (P _app) for SEDDS (5.26 ± 1.10 × 10^-8 cm/s) was found to be similar to that of SEDDS with bioenhancers (5.11 ± 1.05 × 10^-8 cm/s). In oral bioavailability study in rat, SEDDS demonstrated a 4-fold and 2.5-fold higher AUC_0-∞ than RLX suspension (control) and marketed product, respectively. No additional improvement in permeability and bioavailability was offered by inclusion of piperine and quercetin (bioenhancers) in the SEDDS.

Preparation and In Vitro/In Vivo Evaluation of Puerarin Solid Self-Microemulsifying Drug Delivery System by Spherical Crystallization Technique

The aim of this work was to establish a method for preparing stable and controllable solid self-microemulsifying drug delivery system (S-SMEDDS) by spherical crystallization technique, which was explored for promoting the dissolution, oral bioavailability, and process efficiency. Solubility test, preparation of liquid self-microemulsifying drug delivery system (L-SMEDDS), and the obtained ternary phase diagrams test have been performed to screen and optimize the composition of LSMEDDS. The optimized formulation was used to prepare puerarin solid self-microemulsifying drug delivery system (Pue-SSMEDDS) by spherical crystallization technique. Droplet size and morphological analysis of the optimal Pue-SSMEDDS were determined to evaluate the final formulation. And the Pue-SSMEDDS was also assessed by flowability study, angle of repose, Carr's index, and flow velocity. Furthermore, the vitro dissolution and pharmacokinetic profile in vivo were analyzed. The study in vitro showed the Pue-SSMEDDS could disperse in the dispersion medium within 60 s and was spherical with the particle size of 19.66 nm and zeta potential of -28.3 mV. It could keep stable at low temperature and seal condition for 3 months. In vivo pharmacokinetic experiments of rats, the mean plasma concentration of self-microemulsion group was much higher than that of conventional tablets and could play a long-lasting efficacy, while there was no significant difference between the LSMEDDS and S-SMEDDS. The results suggested the potential of S-SMEDDS could improve the oral bioavailability of poorly water-soluble drug, such as puerarin.

Nanoemulsifying drug delivery system to improve the bioavailability of piroxicam

OBJECTIVE

The aim of this study is to develop and characterize self-nanoemulsifying drug delivery system (SNEDDS) of piroxicam in liquid and solid forms to improve its dissolution, absorption and therapeutic efficacy.

MATERIALS AND METHODS

The generation of liquid SNEDDS (L-SNEDDS) was composed of soybean or coconut oil/Tween 80/Transcutol HP (12/80/8%w/w) and it was selected as the optimized formulation based on the solubility study and pseudo-ternary phase diagram. Optimized L-SNEDDS and liquid supersaturatable SNEDDS (L-sSNEDDS) preparations were then adsorbed onto adsorbents and formulated as directly compressed tablets.

RESULTS AND DISCUSSION

The improved drug dissolution rate in the solid supersaturatable preparation (S-sSNEDDS) may be due to the formation of a nanoemulsion and the presence of drug in an amorphous state with hydrogen bond interaction between the drug and SNEDDS components. In vivo pharmacokinetic studies on eight healthy human volunteers showed a significant improvement in the oral bioavailability of piroxicam from S-sSNEDDS (F12) compared with both the pure drug (PP) and its commercial product (Feldene^®) (commercial dosage form (CD)). The relative bioavailability of S-sSNEDDS (F12) relative to PP or CD was about 151.01 and 98.96%, respectively.

CONCLUSION

The obtained results ratify that S-sSNEDDS is a promising drug delivery system to enhance the oral bioavailability of piroxicam.

Development, optimization and in vitro evaluation of norcantharidin loadedself-nanoemulsifying drug delivery systems (NCTD-SNEDDS)

This study focused on developing a self-nanoemulsifying drug delivery system (SNEDDS) containing bioactive surfactants under an efficient screening approach for overcoming problems associated with the delivery of norcantharidin (NCTD), a high dose chemotherapy agent having pH dependent solubility. Preliminary screening was implemented to select proper components combination. Besides the solubility of NCTD in the oil phase, emulsifying efficiency, droplet size and size distribution were also employed to select components of the SNEDDS. Moreover, the influence of surfactant and co-surfactant on the interfacial tension and droplets of nanoemulsions were investigated to further understand the mechanism of spontaneous emulsification. Co-surfactant addition promoted the emulsification via reducing the water/oil interfacial tension and viscosity. Ternary phase diagrams were constructed to investigate the phase behavior and designate the optimum systems. The alternative formulations were characterized for cloud point, dilution robustness, droplet size, polydispersity index (PDI) and transmission electron microscopy (TEM). In vitro dissolution study showed that the dissolution rate of optimized formulation (NCTD 10 mg/g, EO 50 wt.%, Cremophor EL 35 wt.%, ethylene glycol 15 wt.%) was slower than drug suspension under the same conditions, confirming that the developed SNEDDS formulation would exhibit sustained release potential.

Novel Solid Self-Nanoemulsifying Drug Delivery System (S-SNEDDS) for Oral Delivery of Olmesartan Medoxomil: Design, Formulation, Pharmacokinetic and Bioavailability Evaluation

The main purpose of this study was to develop a solid self-nanoemulsifying drug delivery system (S-SNEDDS) of Olmesartan (OLM) for enhancement of its solubility and dissolution rate. In this study, liquid SNEDDS containing Olmesartan was formulated and further developed into a solid form by the spray drying technique using Aerosil 200 as a solid carrier. Based on the preliminary screening of different unloaded SNEDDS formulae, eight formulae of OLM loaded SNEEDS were prepared using Capryol 90, Cremophor RH40 and Transcutol HP as oil, surfactant and cosurfactant, respectively. Results showed that the mean droplet size of all reconstituted SNEDDS was found to be in the nanometric range (14.91–22.97 nm) with optimum PDI values (0.036–0.241). All formulae also showed rapid emulsification time (15.46 ± 1.34–24.17 ± 1.47 s), good optical clarity (98.33% ± 0.16%–99.87% ± 0.31%) and high drug loading efficiency (96.41% ± 1.20%–99.65% ± 1.11%). TEM analysis revealed the formation of spherical and homogeneous droplets with a size smaller than 50 nm. In vitro release of OLM from SNEDDS formulae showed that more than 90% of OLM released in approximately 90 min. Optimized SNEDDS formulae were selected to be developed into S-SNEDDS using the spray drying technique. The prepared S-SNEDDS formulae were evaluated for flow properties, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), reconstitution properties, drug content and in vitro dissolution study. It was found that S-SNEDDS formulae showed good flow properties and high drug content. Reconstitution properties of S-SNEDDS showed spontaneous self-nanoemulsification and no sign of phase separation. DSC thermograms revealed that OLM was in solubilized form and FTIR supported these findings. SEM photographs showed smooth uniform surface of S-SNEDDS with less aggregation. Results of the in vitro drug release showed that there was great enhancement in the dissolution rate of OLM. To clarify the possible improvement in pharmacokinetic behavior of OLM S-SNEDDS, plasma concentration-time curve profiles of OLM after the oral administration of optimized S-SNEDDS formula (F3) were compared to marketed product and pure drug in suspension. At all time points, it was observed that OLM plasma concentrations in rats treated with S-SNEDDS were significantly higher than those treated with the drug in suspension and marketed product.

Development of self-nanoemulsifying drug delivery systems for the enhancement of solubility and oral bioavailability of fenofibrate, a poorly water-soluble drug

Background

Self-nanoemulsifying drug delivery systems (SNEDDS) have become a popular formulation option as nanocarriers for poorly water-soluble drugs. The objective of this study was to investigate the factor that can influence the design of successful lipid formulation classification system (LFCS) Type III SNEDDS formulation and improve the oral bioavailability (BA) of fenofibrate.

Materials and methods

LFCS Type III SNEDDS were designed using various oils, water-soluble surfactants, and/or cosolvents (in considering the polarity of the lipids) for the model anticholesterol drug, fenofibrate. The developed SNEDDS were assessed visually and by measurement of the droplet size. Equilibrium solubility of fenofibrate in the SNEDDS was conducted to find out the maximum drug loading. Dynamic dispersion studies were carried out (1/100 dilution) in water to investigate how much drug stays in solution after aqueous dispersion of the formulation. The BA of SNEDDS formulation was evaluated in the rat.

Results

The results from the characterization and solubility studies showed that formulations containing mixed glycerides were highly efficient SNEDDS as they had higher solubility of the drug and produced nanosized droplets. The dispersion studies confirmed that SNEDDS (containing polar mixed glycerides) can retain >98% drug in solution for >24 hours in aqueous media. The in vivo pharmacokinetics parameters of SNEDDS formulation in comparison with pure drug showed significant increase in C_max and AUC_0–t, ~78% and 67%, respectively. The oral BA of fenofibrate from SNEDDS in rats was ~1.7-fold enhanced as compared with the BA from pure drug.

Conclusion

Fenofibrate-loaded LFCS Type III SNEDDS formulations could be a potential oral pharmaceutical product for administering the poorly water-soluble drug, fenofibrate, with an enhanced oral BA.

Development and application of an ex vivo fosphenytoin nasal bioconversion/permeability evaluation method

There is an increasing interest in the intranasal delivery of central nervous system-active drugs due to the existence of a direct nose-to-brain connection. However, poor solubility limits the amount of drug that can be administered within an aqueous solution. In the present work, the objectives were to develop an ex vivo bioconversion/permeability evaluation method and to study the ex vivo bioconversion of the hydrophilic phosphate ester prodrug fosphenytoin (FOS) to the active drug phenytoin (PHT) and their comparative nasal permeation. Bioconversion/permeability studies were performed in excised porcine nasal mucosa mounted in Ussing chambers. The physical integrity of the tissues was evaluated by measurement of the transepithelial electrical resistance (TEER). The simultaneous quantitative assay of FOS, PHT and its major metabolite, 5-(4-hydroxyphenyl)-5-phenylhydantoin (HPPH) was developed and validated according to international guidelines using a liquid chromatography analytical method. The FOS bioconversion rate and PHT and FOS apparent permeability coefficients (Papp) were determined at different time points. FOS bioconversion was also qualitatively investigated in human nasal mucus. The developed liquid chromatography method combines a fast and inexpensive sample preparation with inactivation of the enzymatic metabolism of the prodrug during sample manipulation and storage. It was linear, precise, accurate, and presented a high analyte recovery. FOS was converted ex vivo to PHT but the metabolite HPPH was not detected. The bioconversion rate increased with FOS concentration and with time, which suggests a diffusion-limited process. FOS was also converted to its active drug by human nasal mucus. A novel mathematical data analysis method was developed to reduce the bias introduced by variable mucosal TEER in the permeability results. At comparable FOS and PHT concentrations the ln(Papp(PHT)) of both compounds showed little difference, which indicates that the use of a hydrophilic and charged prodrug did not hinder overall drug permeation. At the highest tested FOS concentration it was possible to quantify FOS in the receiver chambers, meaning that at a sufficiently high concentration the FOS permeation rate overcame its bioconversion rate. The ln(Papp(PHT)) tended to similar equilibrium values as the assay progressed, but with higher FOS concentrations that equilibrium was attained faster. Acidic pH reduced the permeability of both PHT and FOS. The developed bioconversion/permeability evaluation method will constitute an important tool to select the most promising formulations before proceeding to in vivo studies. Importantly, it allowed the demonstration of phosphatase activity and FOS bioconversion in nasal mucosa, as well as the prodrug's nasal permeation potential. Furthermore, this study demonstrates the possibility of formulating phosphate prodrugs of poorly soluble central nervous system-active drugs as a strategy to increase the solubilized drug doses administered through the nasal route.

Development of Solid Self-Emulsifying Formulation for Improving the Oral Bioavailability of Erlotinib

To improve the solubility and oral bioavailability of erlotinib, a poorly water-soluble anticancer drug, solid self-emulsifying drug delivery system (SEDDS) was developed using solid inert carriers such as dextran 40 and Aerosil® 200 (colloidal silica). The preliminary solubility of erlotinib in various oils, surfactants, and co-surfactants was determined. Labrafil M2125CS, Labrasol, and Transcutol HP were chosen as the oil, surfactant, and co-surfactant, respectively, for preparation of the SEDDS formulations. The ternary phase diagram was evaluated to show the self-emulsifying area. The formulations were optimized using the droplet size and polydispersity index (PDI) of the resultant emulsions. Then, the optimized formulation containing 5% Labrafil M2125CS, 65% Labrasol, and 30% Transcutol was spray dried with dextran or Aerosil® and characterized for surface morphology, crystallinity, and pharmacokinetics in rats. Powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC) exhibited the amorphous form or molecular dispersion of erlotinib in the formulations. The pharmacokinetic parameters of the optimized formulations showed that the maximum concentration (C max) and area under the curve (AUC) of erlotinib were significantly increased, compared to erlotinib powder (p < 0.05). Thus, this SEDDS could be a promising method for enhancing the oral bioavailability of erlotinib.

Quality-by-design based development of a self-microemulsifying drug delivery system to reduce the effect of food on Nelfinavir mesylate

Poor aqueous solubility and moderate permeability of Nelfinavir mesylate (NFM) leads to high variability in absorption after oral administration. To improve the solubility and bioavailability of NFM, the self microemulsifying drug delivery system (SMEDDS) was developed. For this purpose, Quality by design (QbD) approach employing D-optimal mixture design was used to prepare SMEDDS of NFM. Further, the software generated numerically optimized SMEDDS were developed by utilizing desirability function. Maisine 35-1, Tween 80, and Transcutol HP were identified as oil, surfactant, and co-surfactant that had best solubility for NFM. Ternary phase diagrams were plotted to identify the self-emulsification region. Dissolution of putative NFM in simulated fasted or fed small intestinal conditions, respectively, predicted that there is a positive food effect. However, NFM loaded SMEDDS showed absence of food effect with no significant difference in dissolution performance either in Fasted or fed state simulated intestinal fluid (FaSSIF or FeSSIF) biorelevent dissolution media. The prepared SMEDDS were thermodynamically stable with droplet size (121 nm), poly dispersity index (PDI) (0.198) and emulsification time (<1 min). Transmission electron microscopy (TEM) analysis confirmed the spherical shape of the reconstituted SMEDDS droplets. The ex vivo performance revealed 4.57 fold enhancement in the apparent permeability of NFM as compared to NFM suspension. The animal pharmacokinetic analysis in New Zealand strain rabbits indicated food effect on pure NFM suspension. However, absence of food effect and 3.5-3.6 fold enhancement in the oral bioavailability was observed when NFM was formulated into SMEDDS. Thus, it could be envisaged that development of SMEDDS formulation of NFM could be one of the best alternative to enhance oral bioavailability of NFM.

The role of lipid-based drug delivery systems for enhancing solubility of highly selective antiviral agent acyclovir

The study aimed to improve the aqueous solubility and dissolution rate of acyclovir (ACV) using self-emulsifying lipid formulations (SEDDS/SMEDDS). ACV was formulated in various SEDDS/SMEDDS using wide ranges of oils (mono-/di-/triglycerides), nonionic surfactants and water-soluble cosolvents with the aid of phase behavior studies. The drug solubility was determined in anhydrous, 10% and 99% diluted formulations. Drug precipitation and release profiles of the SEDDS/SMEDDS were also investigated. The ACV was highly soluble in the formulations containing high concentration of hydrophilic materials. The addition of propylene glycol (PG) significantly enhanced the drug solubility. In addition, with only 1% 0.1 M HCl, the drug solubility improved 10-fold higher without any precipitation. In the dissolution studies, the representative SEDDS/SMEDDS showed superior release profiles (>90% ACV released) than marketed Zovirax® suspension (<26% released). Formulations containing water-soluble cosolvent (e.g. PG), were the most suitable systems for ACV due to the extensive drug solubilization and release profile.

Spontaneous emulsification of nifedipine-loaded self-nanoemulsifying drug delivery system

Self-nanoemulsifying drug delivery system (SNEDDS) can be used to improve dissolution of poorly water-soluble drugs. The objective of this study was to prepare SNEDDS by using ternary phase diagram and investigate their spontaneous emulsifying property, dissolution of nifedipine (NDP), as well as the pharmacokinetic profile of selected SNEDDS formulation. The results showed that the composition of the SNEDDS was a great importance for the spontaneous emulsification. Based on ternary phase diagram, the region giving the SNEDDS with emulsion droplet size of less than 300 nm after diluting in aqueous medium was selected for further formulation. The small-angle X-ray scattering curves showed no sharp peak after dilution at different percentages of water, suggesting non-ordered structure. The system was found to be robust in different dilution volumes; the droplet size was in nanometer range. In vitro dissolution study showed remarkable increase in dissolution of NDP from SNEDDS formulations compared with NDP powders. The pharmacokinetic study of selected SNEDDS formulation in male Wistar rats revealed the improved maximum concentration and area under the curve. Our results proposed that the developed SNEDDS formations could be promising to improve the dissolution and oral bioavailability of NDP.

K K, V NSKV. Porous polystyrene spheres loaded self nano-emulsifying systems of rosuvastatin calcium

The aim of the study was to investigate potential of Solid Self Nano-Emulsifying Drug Delivery System (SNEDDS) for enhancing solubility and oral bioavailability of Rosuvastatin Calcium (RC).

Self-Microemulsifying Drug Delivery Systems: An Attractive Strategy for Enhanced Therapeutic Profile

Ease of administration and painless approach made oral route the most preferred. Poor oral bioavailability is pronounced with the majority of recent active ingredients because of dissolution rate limited absorption. Failure to attain intended therapeutic effect of the poor water soluble drugs by this route led to development of novel drug delivery systems which will fulfill therapeutic needs with minimum dose. Although many formulation approaches like solid dispersions, complexation, pH modification, and cocrystals exist, lipid based delivery systems finding increased appliance with the apparent increase in absorption of drug. Among lipid based formulations, self-microemulsifying formulations (droplet size < 100 nm) are evident to improve the oral bioavailability of hydrophobic drugs primarily due to their efficiency in facilitating solubilization and in presenting the hydrophobic drug in solubilized form whereby dissolution process can be circumvented. Various components that are used to formulate these dosage forms like surfactants and lipids contribute to the overall improvement in oral bioavailability via promoting the lymphatic transport; thereby hepatic first pass metabolism can be surmounted. The present paper gives exhaustive information on the formulation design and characterization of SMEDDS along with the probable mechanisms by which the bioavailability can be improved with SMEDDS.

Comparison of α2-macroglobulin synthesis by juvenile vs. mature rats after identical inflammatory stimulation

Synthesis of α2-macoglobulin (α2M) by 3-week-old juvenile rats was compared to that of mature 7- and 11-week-old rats. Serum concentrations of α2M, interleukin (IL)-6- and cytokine-induced neutrophil chemoattractant (CINC)-1 were measured by enzyme-linked immunosorbent assay. The area under the concentration vs. time curve (AUC) for α2M was significantly different among the three groups. The synthesis of α2M increased in an age-dependent manner. No significant difference was observed for the AUC of IL-6, but that of CINC-1 in 3-week-old rats was significantly lower than that in 7- or 11-week-old rats. These results suggest that synthesis of α2M was increased in mature compared to juvenile rats, possibly due to differences in liver function. The maximum concentration of CINC-1 in 3-week-old rats was observed 6 h after turpentine oil injection. The serum concentrations of IL-6 and CINC-1 increased more quickly in juvenile rats than in mature rats after inflammatory stimulation.