Comparative Study on the Effects of Some Polyoxyethylene Alkyl Ether and Sorbitan Fatty Acid Ester Surfactants on the Performance of Transdermal Carvedilol Proniosomal Gel Using Experimental Design

The aim of this work was to investigate the effects of formulation variables on development of carvedilol (CAR) proniosomal gel formulations as potential transdermal delivery systems. Different non-ionic surfactants; polyoxyethylene alkyl ethers, namely Brij 78, Brij 92, and Brij 72; and sorbitan fatty acid esters (Span 60) were evaluated for their applicability in preparation of CAR proniosomal gels. A 2³ full factorial design was employed to evaluate individual and combined effects of formulation variables, namely cholesterol content, weight of proniosomes, and amount of CAR added on performance of proniosomes. Prepared proniosomes were evaluated regarding entrapment efficiency (EE%), vesicle size, and microscopic examination. Also, CAR release through cellulose membrane and permeation through hairless mice skin were investigated. Proniosomes prepared with Brij 72 and Span 60 showed better niosome forming ability and higher EE% than those prepared with Brij 78 and Brij 92. Higher EE% was obtained by increasing both weight of proniosomes and amount of CAR added, and decreasing cholesterol content. Release rate through cellulose membrane was inversely affected by weight of proniosomes. In Span 60 proniosomes, on increasing percent of cholesterol, a decrease in release rate was observed. While in Brij 72 proniosomes, an enhancement in release rate was observed on increasing amount of CAR added. Permeation experiments showed that skin permeation was mainly affected by weight of proniosomes and that Span 60 proniosomal gels showed higher permeation enhancing effect than Brij 72. Proniosomal gel could constitute a promising approach for transdermal delivery of CAR.     

Proniosomal Oral Tablets for Controlled Delivery and Enhanced Pharmacokinetic Properties of Acemetacin

Free-flowing proniosomal powders of acemetacin (AC) were prepared using the slurry method and maltodextrin as carrier. Positively charged proniosomes composed of 70:20:10 of Span 60/cholesterol (Chol)/stearylamine (SA), respectively, were successively compressed into tablets using direct compression method. The tablets were characterized for weight variability, friability, hardness, drug content uniformity, and dissolution properties. The in vivo evaluation of the prepared proniosomes (powder or tablet forms) after oral administration was investigated by the determination of AC and its active metabolite indomethacin (IND) in the blood of albino rabbits. Results indicated that the increase of Chol from 10% to 20% markedly reduced the efflux of the drug. Further Chol addition from 30% to 50% led to increased AC release rates. The proniosome tablets of AC showed greater hardness and disintegration time and less friability than AC plain tablets. The dissolution of proniosomal tablets indicated a lower drug release percentage compared to powdered proniosomes and AC plain tablets. The mean pharmacokinetic parameters of AC and IND from different formulations indicated increased t_1/2 and area under the curve (AUC) of both AC and IND for proniosomal tablets compared with both proniosomal powders and AC plain tablets. This study suggested the formulation of AC proniosomal powder into tablets to control and extend its pharmacologic effects.KEY WORDS: acemetacin, proniosomes, sustained-release tablet, pharmacokinetics     

In Vitro Evaluation of Proniosomes as a Drug Carrier for Flurbiprofen

The purpose of the present investigation is to formulate and evaluate proniosomal transdermal carrier systems for flurbiprofen. Proniosomes were prepared using various non-ionic surfactants, namely span 20 (Sp 20), span 40 (Sp 40), span 60 (Sp 60) and span 80 (Sp 80) without and with cholesterol at percentages ranging from 0% to 50%. The effect of surfactant type and cholesterol content on drug release was investigated. Drug release was tested by diffusion through cellophane membrane and rabbit skin. Drug release from the prepared systems was compared to that from flurbiprofen suspensions in distilled water and HPMC (hydroxypropylmethylcellulose) gels. In case of Sp 20 and Sp 80, the added amount of cholesterol affected the preparation type to be either proniosomal alcoholic solutions or liquid crystalline gel systems. On the other hand, both Sp 40 and Sp 60 produced gel systems in presence or absence of cholesterol. Microscopic observations showed that either proniosomal solutions or gel formulations immediately converted to niosomal dispersions upon hydration. Due to the skin permeation barrier, rabbit skin showed lower drug diffusion rates compared to cellophane membrane. The proniosomal composition controlled drug diffusion rates to be either faster or slower than the prepared flurbiprofen suspensions in HPMC gels or distilled water, respectively. In conclusion, this study demonstrated the possibility of using proniosomal formulations for transdermal drug delivery.     

Design and evaluation of proniosomes as a carrier for ocular delivery of lomefloxacin HCl

The current investigation aims to develop and evaluate novel ocular proniosomal gels of lomefloxacin HCl (LXN); in order to improve its ocular bioavailability for the management of bacterial conjunctivitis. Proniosomes were prepared using different types of nonionic surfactants solely and as mixtures with Span 60. The formed gels were characterized for entrapment efficiency, vesicle size, and in vitro drug release. Only Span 60 was able to form stable LXN-proniosomal gel when used individually while the other surfactants formed gels only in combination with Span 60 at different ratios. The optimum proniosomal gel; P-LXN 7 (Span 60:Tween 60, 9:1) appeared as spherical shaped vesicles having high entrapment efficiency (>80%), appropriate vesicle size (187?nm) as well as controlled drug release over 12?h. Differential scanning calorimetry confirmed the amorphous nature of LXN within the vesicles. Stability study did not show any significant changes in entrapment efficiency or vesicle size after storage for 3 months at 4?°C. P-LXN 7 was found to be safe and suitable for ocular delivery as proven by the irritancy test. The antibacterial activity of P-LXN 7 evaluated using the susceptibility test and topical therapy of induced ocular conjunctivitis confirmed the enhanced antibacterial therapeutic efficacy of the LXN-proniosomal gel compared to the commercially available LXN eye drops.     

Formulation of Niosomal Gel for Enhanced Transdermal Lopinavir Delivery and Its Comparative Evaluation with Ethosomal Gel

The aim was to develop niosomal gel as a transdermal nanocarrier for improved systemic availability of lopinavir. Niosomes were prepared using thin-film hydration method and optimized for molar quantities of Span 40 and cholesterol to impart desirable characteristics. Comparative evaluation with ethosomes was performed using ex vivo skin permeation, fluorescence microscopy, and histopathology studies. Clinical utility via transdermal route was acknowledged using in vivo bioavailability study in male Wistar rats. The niosomal formulation containing lopinavir, Span 40, and cholesterol in a molar ratio of 1:0.9:0.6 possessed optimally high percentage of drug entrapment with minimum mean vesicular diameter. Ex vivo skin permeation studies of lopinavir as well as fluorescent probe coumarin revealed a better deposition of ethosomal carriers but a better release with niosomal carriers. Histopathological studies indicated the better safety profile of niosomes over ethosomes. In vivo bioavailability study in male Wistar rats showed a significantly higher extent of absorption (AUC_0→∞, 72.87 h × μg/ml) of lopinavir via transdermally applied niosomal gel as compared with its oral suspension. Taken together, these findings suggested that niosomal gel holds a great potential of being utilized as novel, nanosized drug delivery vehicle for transdermal lopinavir delivery.KEY WORDS: ethosomes, lopinavir, niosomes, transdermal     

<Emphasis Type="Italic">In Vitro</Emphasis> and <Emphasis Type="Italic">In Vivo</Emphasis> Evaluation of Proniosomes Containing Celecoxib for Oral Administration

The objectives of this research were to prepare celecoxib proniosomes and evaluate the influence of proniosomal formulation on the oral bioavailability of the drug in human volunteers. A new proniosomal delivery system for a poorly water-soluble drug such as celecoxib was developed and subjected to in vitro and in vivo studies. Proniosomes were prepared by sequential spraying method, which consisted of cholesterol, span 60, and dicetyl phosphate in a molar ratio of 1:1: 0.1, respectively. The average entrapment percent of celecoxib proniosome-derived niosomes was about 95%. The prepared proniosomes showed marked enhancement in the dissolution of celecoxib as compared to pure drug powder. The bioavailability of 200 mg single dose of both celecoxib proniosomal formulation and a conventional marketed celecoxib capsule was studied in human volunteers. The obtained results show that the proniosomal formulation significantly improved the extent of celecoxib absorption than conventional capsule. The mean relative bioavailability of the proniosomal formulation to the conventional capsule was 172.06 ± 0.14%. The mean T _max for celecoxib was prolonged when given as proniosomal capsule. There was no significant difference between the values of K _el and t _1/2 for both celecoxib preparations. In conclusion, the proniosomal oral delivery system of celecoxib with improved bioavailability was established.     

Sorbitan ester niosomes for topical delivery of rofecoxib

The aim of the present investigation is to encapsulate rofecoxib in niosomes and incorporate the prepared niosomes into dermal gel base for sustained therapeutic action. Niosomes were prepared by lipid film hydration technique and were analyzed for size, entrapment efficiency and drug retention capacity. Niosomal vesicles were then incorporated into blank carbopol gel to form niosomal gel. The in vitro permeation study across pig skin was performed using Keshary-Chien glass diffusion cell. The size and entrapment efficiency of the niosomal vesicles increased with gradual increase in HLB value of nonionic surfactants used. Maximum drug entrapment was observed with Span 20 with HLB value of 8.6 and drug leakage from vesicles was less at refrigerated condition than at the room temperature. Higher proportion of cholesterol made the niosomal formulation more stable with high drug retention properties. The niosomal gel showed a prolong drug release behavior compared to plain drug gel. Differential scanning calorimetric study of drug loaded gel and pig skin after permeation study confirmed inertness of carbopol gel base toward rofecoxib and absence of drug metabolism in the skin during permeation study, respectively. The niosomal formulations were successfully prepared by lipid film hydration technique using cholesterol and Span as nonionic surfactant. Presence of cholesterol made niosomes more stable with high drug entrapment efficiency and retention properties. The lower flux value of niosomal gel as compared to plain drug gel across pig skin assured the prolong drug release behavior with sustained action.     

Preparation and evaluation of niosome gel containing acyclovir for enhanced dermal deposition

Niosomes suggest a versatile vesicle delivery system with possible transport of drugs via topical route for skin delivery. The aim of the present research was to optimize niosome gel formulation of acyclovir and to evaluate in both in vitro and in vivo rabbit model. Niosome formulations were formulated by coacervation phase separation technique with different ratios of nonionic surfactants, phospholipids and cholesterol using 3² factorial design. Altering the surfactant concentration has influenced the drug entrapment, but not vesicle size. At high surfactant combinations, the acyclovir release from niosomes was strongly influenced by cholesterol:lecithin ratio. Ex vivo drug permeation data indicate substantial difference in flux values and was influenced by the niosome composition. Ex vivo studies using formulation (B₈) for drug deposition indicate greater amount of niosome being diffused into the skin layers and formed a depot, compared to commercial acyclovir cream (control). Two distinct dermatopharmacokinetic profiles were observed, in vivo, for niosome gel formulation (B₈) and control, which were analog to the profiles observed with ex vivo deposition studies. In vivo plasma drug level suggests low systemic exposure of acyclovir (C_max: 9.44?±?2.27?ng/mL and 14.54?±?3.11?ng/mL for niosome formulation and control, respectively). Comparison of kinetic data of acyclovir in the stratum corneum and plasma signifies that the niosome formulation forms a depot in the epidermis or dermis region. This study concludes that the niosome gel formulation (B₈) could be a viable vesicular system for an impressive transdermal delivery of acyclovir by topical application.     

Nanoemulsion based gel for transdermal delivery of meloxicam: Physico-chemical,mechanistic investigation

AimsThe aim of the present investigation was to develop a nanoemulsion (NE) gel formulation for the transdermal delivery of meloxicam (MLX) in order to ensure maximum controlled and sustained drug release capacity.Main methodsThe MLX containing NE gel was prepared and characterized for particle size, zeta potential, pH, rheology, in vitro drug release, in vitro skin permeation, and in vitro hemolysis. Differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) of MLX-NE gel treated rat skin was performed to investigate the skin permeation mechanism of meloxicam from NE gel. Skin permeation potential of the developed gel formulation was assessed using confocal laser scanning microscopy (CLSM). The in vivo toxicity of MLX-NE gel was assessed by histopathological examination in rat. The rat paw edema test was performed to evaluate the anti-inflammatory activity of MLX-NE gel.Key findingsPercutaneous absorption studies demonstrated a higher permeation of meloxicam from NE gel, than the drug solution. FTIR and DSC studies supported stratum corneum lipid extraction as a possible penetration enhancer mechanism for MLX-NE gel. CLSM studies confirmed the permeation of the NE gel formulation to the deeper layers of the skin (up to 130 μm). MLX-NE gel turned out to be non-irritant, biocompatible, and provided maximum inhibition of paw edema in rats over 24 h in contrast to MLX solution.SignificanceThe nanoemulsion gel formulation may hold promise as an effective alternative for the transdermal delivery of meloxicam.     

Development and characterization of a novel controlled release drug delivery system based on nanostructured lipid carriers gel for meloxicam

Aim

The main objective of the current investigation was to develop nanostructured lipid carriers (NLC) based gel for the enhancement of transdermal absorption of meloxicam (MLX) to achieve local as well as systemic drug action without concurrent gastrointestinal toxicity.

Main methods

NLC gel containing MLX was prepared and characterized for particle size, polydispersity, zeta potential, pH, rheology, entrapment efficiency, occlusion factor, and thermal behavior. In vitro drug release, in vitro skin permeation and deposition studies were carried out using Franz diffusion cells. Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) of MLX-NLC gel treated stratum corneum (SC) were undertaken to get an insight into the skin permeation enhancement mechanism of MLX-NLC gel. Toxicity potential of the developed gel formulation was assessed by in vitro hemolysis and histopathological examinations. The rat paw edema test was performed to evaluate the anti-inflammatory activity of MLX-NLC gel.

Key findings

MLX-NLC gel demonstrated sustained release and enhanced the skin permeation and deposition of meloxicam especially into the dermis in comparison to meloxicam gel (control). MLX-NLC had an impact on the barrier properties of the skin and acted via protein and lipid modifications in the stratum corneum. MLX-NLC gel turned out to be hemocompatible, non-irritant, and non toxic with significant anti-inflammatory activity.

Significance

The results suggest that NLC gel could be a promising carrier for the transdermal delivery of meloxicam.     

Solid lipid nanoparticles for transdermal delivery of avanafil: optimization,formulation, in-vitro and ex-vivo studies

Context: Avanafil (AVA) is used in the treatment of erectile dysfunction, but is reported for its poor aqueous solubility. Solid lipid nanoparticles (SLNs) are lipid carriers that can greatly enhance drug solubility and bioavailability.

Objective: This work was aimed to formulate and optimize AVA SLNs with subsequent loading into hydrogel films for AVA transdermal delivery.

Materials and methods: AVA SLNs were prepared utilizing homogenization followed by ultra-sonication technique. The prepared SLNs were characterized for particle size, charge, surface morphology and drug content. The optimized SLNs formulation was incorporated into transdermal films prepared using HPMC and chitosan. Hydrogel films were evaluated for ex-vivo rat skin permeation using automated Franz diffusion cells. The permeation parameters and the release mechanism were evaluated. The transdermal permeation of the prepared AVA SLNs through the skin layers was studied using confocal laser scanning microscope.

Results: Lipid concentration and % of oil in lipid had a pronounced effect on particle size while, entrapment efficiency was significantly affected by lipid concentration and % of cholesterol. The optimized AVA SLNs showed particle size and entrapment efficiency of 86?nm and 85.01%, respectively. TEM images revealed spherecity of the particles. High permeation parameters were observed from HPMC films loaded with AVA SLNs. The release data were in favor of Higuchi diffusion model. The prepared AVA SLNs were able to penetrate deeper in skin layers.

Conclusion: HPMC transdermal film-loaded AVA SLNs is an effective and alternative to per-oral drug administration.     

Nano-transfersomal formulations for transdermal delivery of asenapine maleate: in vitro and in vivo performance evaluations

Context: Asenapine maleate (ASPM) is an antipsychotic drug for the treatment of schizophrenia and bipolar disorder. Extensive metabolism makes the oral route inconvenient for ASPM.

Objective: The objective of this study is to increase ASPM bioavailability via transdermal route by improving the skin permeation using combined strategy of chemical and nano-carrier (transfersomal) based approaches.

Materials and methods: Transfersomes were prepared by the thin film hydration method using soy-phosphatidylcholine (SPC) and sodium deoxycholate (SDC). Transfersomes were characterized for particle size, polydispersity index (PDI), zeta potential (ZP), entrapment efficiency, surface morphology, and in vitro skin permeation studies. Various chemical enhancers were screened for skin permeation enhancement of ASPM. Optimized transfersomes were incorporated into a gel base containing suitable chemical enhancer for efficient transdermal delivery. In vivo pharmacokinetic study was performed in rats to assess bioavailability by transdermal route against oral administration.

Results and discussion: Optimized transfersomes with drug:SPC:SDC weight ratio of 5:75:10 were spherical with an average size of 126.0?nm, PDI of 0.232, ZP of??43.7?mV, and entrapment efficiency of 54.96%. Ethanol (20% v/v) showed greater skin permeation enhancement. The cumulative amount of ASPM permeated after 24?h (Q₂₄) by individual effect of ethanol and transfersome, and in combination was found to be 160.0, 132.9, and 309.3?μg, respectively, indicating beneficial synergistic effect of combined approach. In vivo pharmacokinetic study revealed significant (p?Conclusion: Dual strategy of permeation enhancement was successful in increasing the transdermal permeation and bioavailability of ASPM.     

Metformin hydrochloride and wound healing: from nanoformulation to pharmacological evaluation

Abstract

Niosomes as drug delivery systems have the ability to decrease drugs' side effects and increase their therapeutic effectiveness. Metformin HCl is an oral antihyperglycemic agent belonging to biguanides. It is the most commonly chosen drug as a startup therapy for patients newly diagnosed with type 2 diabetes. This study aims to encapsulate metformin HCl inside niosomes to be used as a transdermal formulation helping to prolong its antidiabetic effect and investigate its ability to enhance wound healing in diabetic patients. Thin film hydration method was used to prepare metformin HCl niosomes using different proportions of Span 60, Span 40, Tween 80, and cholesterol. All formulations were characterized using transmission electron microscope, zeta potential, and vesicle size. In vitro release studies, stability studies and in vivo evaluation were conducted on selected niosomal formulations. The results of entrapment efficiency ranged from 13% to 32%. Vesicle sizes were determined in nano-range. The in vitro release profile of metformin HCl from niosomes occurred in two consecutive phases. Biological evaluation on diabetic rats revealed that metformin HCl niosomal gel given every 2 days showed a better sustained antidiabetic effect than oral doses given daily. It also showed an improvement in wound healing for diabetic rats given metformin formulations compared to nontreated ones.     

Formulation and development of novel control release transdermal patches of carvedilol to improve bioavailability for the treatment of heart failure

The main aim of this study is to optimize and evaluate transdermal patch of Carvedilol by the use of different polymer and different permeation enhancers which help to release drug in controlled action and thereby increase the bioavailability of the drug. Main objective was to avoid first pass metabolism of Carvedilol. Transdermal patches were developed by solvent evaporation method. The combination of Eudragit RS-100 as rate controlling polymer and Span 80 as a permeation enhancer was found to be ideal formulation (Formulation F7) with maximum drug release i.e. 100.29 ± 0.44 % within 12 h. Formulation F7 showed maximum bioavailability and showed maximum drop of BP at 6 h. From this study the conclusion was, transdermal patch of Carvedilol which contains Eudragit RS-100 polymer and Span 80 as penetration enhancer produced sustained and continued drug release.     

Dry Gel Containing Optimized Felodipine-Loaded Transferosomes: a Promising Transdermal Delivery System to Enhance Drug Bioavailability

Felodipine has a very low bioavailability due to first-pass metabolism. The aim of this study was to enhance its bioavailability by transdermal application. Felodipine-loaded transferosomes were prepared by thin-film hydration using different formulation variables. An optimized formula was designed using statistical experimental design. The independent variables were the used edge activator, its molar ratio to phosphatidylcholine, and presence or absence of cholesterol. The responses were entrapment efficiency of transferosomes, their size, polydispersity index, zeta potential, and percent drug released after 8 h. The optimized formula was subjected to differential scanning calorimetry studies and its stability on storage at 4°C for 6 months was estimated. This formula was improved by incorporation of different permeation enhancers where ex vivo drug flux through mice skin was estimated and the best improved formula was formulated in a gel and lyophilized. The prepared gel was subjected to in vivo study using Plendil® tablets as a reference. According to the calculated desirability, the optimized transferosome formula was that containing sodium deoxycholate as edge activator at 5:1 M ratio to phosphatidylcholine and no cholesterol. The thermograms of this formula indicated the incorporation of felodipine inside the prepared vesicles. None of the tested parameters differed significantly on storage. The lyophilized gel of labrasol-containing formula was chosen for in vivo study. The relative bioavailability of felodipine from the designed gel was 1.7. In conclusion, topically applied lyophilized gel containing felodipine-loaded transferosomes is a promising transdermal delivery system to enhance its bioavailability.     

Design and development of ethosomal transdermal drug delivery system of valsartan with preclinical assessment in Wistar albino rats

Abstract

Valsartan (VLT) is a highly selective and orally active antihypertensive drug. However, its oral administration is associated with drawbacks like low bioavailability. The objective of this study was to design and develop a transdermal delivery system for VLT using ethosomal carriers to investigate their enhanced transdermal delivery potential. VLT ethosomes were prepared by cold method. VLT ethosomes were characterized by scanning electron microscopy. The prepared ethanolic liposomes were characterized to be spherical having low polydispersity of nano-size range with good entrapment efficiency. ETC5 ethosomal suspension with 4% of phospholipon 90H and 40% of ethanol was found to have highest entrapment efficiency, i.e. 80.230?±?0.8748%. The permeation study of ethosomes was evaluated by ex vivo diffusion study through rat abdominal skin using Franz’s diffusion cells and ETC5 ethosomal suspension was found to have highest permeation with flux of 92.819?±?1.539?µg/cm²/h, when compared to the permeation profiles of drug solutions either in water or in a water–ethanol mixture. Transdermal application of ethosomal VLT on Wistar rats showed better and prolonged antihypertensive activity in comparison to orally administered VLT suspension by virtue of transdermal permeation through Wistar rat skin. Histopathological study of skin applied with ETC5 showed intercellular permeation across skin by dissolving intercellular lipids in epidermis without causing any rigorous changes in the skin cellular structure. In conclusion, ethosomes enabled the transdermal permeation of VLT, which amply proves its superiority over oral administration for antihypertensive treatment.     

Topical Delivery of Fenoprofen Calcium <Emphasis Type="Italic">via</Emphasis> Elastic Nano-vesicular Spanlastics: Optimization Using Experimental Design and <Emphasis Type="Italic">In Vivo</Emphasis> Evaluation

The aim of this study was to investigate the potential of surfactant-based nanovesicular system (spanlastics) for topical delivery of fenoprofen calcium (FPCa) to eliminate its oral gastrointestinal adverse effects. FPCa-loaded spanlastics were prepared by thin film hydration (TFH) technique according to a full factorial design to investigate the influence of formulation variables on the drug entrapment efficiency (%EE), particle size (PS), deformability index (DI), and the % drug released after 24 h through the cellulose membrane (Q24h) using Design-Expert® software. The optimized formula (composed of Span 60 and Tween 60 as an edge activator at weight ratio of 8: 2 in presence of Transcutol P as a cosolvent in the hydration media) exhibited the highest %EE (49.91 ± 2.60%), PS of 536.1 ± 17.14 nm, DI of 5.07 ± 0.06 g, and Q24h of 61.11 ± 2.70%; it was also characterized for morphology and physical stability. In vitro release study of FPCa-loaded spanlastic gel and conventional FPCa gel through a synthetic membrane and hairless rat skin were evaluated. The skin permeation study revealed that spanlastic gel exhibited both consistent and prolonged action. Finally, the % inhibition of carrageenan-induced rat paw edema of spanlastic gel was three times higher than the conventional FPCa gel after 24 h. In conclusion, spanlastic-based gel could be a great approach for improving topical delivery of fenoprofen calcium, providing both prolonged and enhanced anti-inflammatory activity in the treatment of arthritis.     

Poloxamer 407-based intranasal thermoreversible gel of zolmitriptan-loaded nanoethosomes: formulation,optimization, evaluation and permeation studies

Zolmitriptan is the drug of choice for migraine, but low oral bioavailability (<50%) and recurrence of migraine lead to frequent dosing and increase in associated side effects. Increase in the residence time of drug at the site of drug absorption along with direct nose to brain targeting of zolmitriptan can be a solution to the existing problems. Hence, in the present investigation, thermoreversible intranasal gel of zolmitriptan-loaded nanoethosomes was formulated by using mucoadhesive polymers to increase the residence of the drug into the nasal cavity. The preparation of ethosomes was optimized by using 3² factorial design for percent drug entrapment efficiency, vesicle size, zeta potential, and polydispersity index. Optimized formulation E6 showed the vesicle size (171.67?nm) and entrapment efficiency (66%) when compared with the other formulations. Thermoreversible gels prepared by using poloxamer 407 showed the phase transition temperature at 32–33?°C which was in line with the nasal physiological temperature. The optimized ethosomes were loaded into the thermoreversible mucoadhesive gel optimized by varying concentrations of poloxamer 407, carbopol 934, HPMC K100, and evaluated for gel strength, gelation temperature, mucoadhesive strength, in vitro drug release, and ex vivo drug permeation, where G3 and G6 were found to be optimized formulations. In vitro drug release was studied by different kinetic models suggested that G3 (n?=?0.582) and G6 (n?=?0.648) showed Korsemeyer–Peppas (K_KP) model indicating non-Fickian release profiles. A permeation coefficient of 5.92 and 5.9?µg/cm² for G3 and G6, respectively, revealed very little difference in release rate after 24?h between both the formulations. Non-toxic nature of the gels on columnar epithelial cells was confirmed by histopathological evaluation.     

Oral delivery of allopurinol niosomes in treatment of gout in animal model

Context: Gout is a painful disorder which does not have an efficient delivery system for its treatment.

Objective: Development and in vitro, in vivo evaluation of allopurinol-loaded nonionic surfactant-based niosomes was envisaged.

Materials and methods: Niosomes were prepared with Span 20 and Tween 20 (1:1 molar ratio) using ether injection method. The formulations were screened for entrapment efficiency, particle size analysis, zeta potential, release kinetics, in vivo activity, and stability studies.

Result: Stable, spherical vesicles of average particle size 304?nm with zeta-potential and entrapment efficiency of 22.2?mV and 79.44?±?0.02%, respectively, were produced. In vitro release study revealed 82.16?±?0.04% release of allopurinol within 24?h. The niosomal formulation was further evaluated for its antigout potential in monosodium urate (MSU) crystal induced gout animal model. The formulation demonstrated significant uric acid level reduction and enhanced antigout activity when compared with the pure allopurinol.

Discussion: The better antigout activity displayed by niosomal formulation could be attributed to sustained release of drug, higher drug solubility within biological fluids, better membrane interaction, smaller size, and presence of cholesterol and surfactant.

Conclusions: This study reveals that niosomes can be an efficient delivery system for the treatment of gout.     

Proultraflexible lipid vesicles for effective transdermal delivery of levonorgestrel: Development,characterization, and performance evaluation

The present investigation aimed at formulation, performance evaluation, and stability studies of new vesicular drug carrier system protransfersomes for transdermal delivery of the contraceptive agent, levonorgestrel. Protransfersome gel (PTG) formulations of levonorgestrel were prepared and characterized for vesicle shape, size, entrapment efficiency, turbidity, and drug permeation across rat skin and were evaluated for their stability. The system was evaluated in vivo for biological assay of progestational activity including endometrial assay, inhibition of the formation of corpora lutea, and weight gain of uterus. The effects of different formulation variables (type of alcohol, type and concentration of surfactant) on transdermal permeability profile were assessed. The optimized PTG formulation showed enhanced in vitro skin permeation flux of 15.82±0.37 μg/cm²/hr as compared to 0.032±0.01 μg/cm²/hr for plain drug solution. PTG also showed good stability and after 2 months of storage there was no change in liquid crystalline nature, drug content, and other characteristic parameters. The peak plasma concentration of levonorgestrel (0.139±0.05 μg/mL) was achieved within 4 hours and maintained until 48 hours by a single topical application of optimized PTG formulation. In vivo performance of the PTG formulation showed increase in the therapeutic efficacy of drug. Results indicated that the optimized protransfersomal formulation of levonorgestrel had better skin permeation potential, sustained release characteristic, and better stability than proliposomal formulation.