Nanosized ethosomal dispersions for enhanced transdermal delivery of nebivolol using intradermal/transfollicular sustained reservoir: in vitro evaluation, confocal laser scanning microscopy, and in vivo pharmacokinetic studies.

Nebivolol (NBV), a BCS class II anti-hypertensive drug, suffers from limited solubility and oral bioavailability. Nanosized ethosomes were adopted as an approach to solubilize and deliver NBV transdermally, as a substitute to oral route. Ethosomal dispersions were prepared employing thin film hydration method. Formulation variables were adjusted to obtain entrapment efficiency; EE > 50%, particle size; PS < 100 nm, zeta potential; ZP > ±25 mV, and polydispersity index; PDI < 0.5. The optimized ethosomal dispersion (OED) showed accepted EE 86.46 ± 0.15%, PS 73.50 ± 0.08 nm, ZP 33.75 ± 1.20 mV, and PDI 0.31 ± 0.07. It also showed enhanced cumulative amount of NBV permeated at 8 h (Q8) 71.26 ± 1.46% and 24 h (Q24) 98.18 ± 1.02%. TEM images denoted spherical vesicles with light colored lipid bi-layer and dark core. Confocal laser scanning microscopy showed deeply localized intradermal and transfollicular permeation of the fluorolabelled OED (FL-OED). Nanosized FL-OED (<100 nm) can permeate through hair follicles creating a drug reservoir for enhanced systemic absorption. OED formulated into transdermal patch (OED-TP1) exhibited accepted physicochemical properties including; thickness 0.14 ± 0.01 mm, folding endurance 151 ± 0.07, surface pH 5.80 ± 0.15, drug content 98.64 ± 2.01%, mucoadhesion 8534 ± 0.03, Q8 87.61 ± 0.11%, and Q24 99.22 ± 0.24%. In vivo pharmacokinetic studies showed significantly enhanced bioavailability of OED-TP1 by 7.9 folds compared to oral Nevilob® tablets (p = 0.0002). It could be concluded that OED-TP1 can be a promising lipid nanocarrier TDDS for NBV and an efficacious alternative route of administration for hypertensive patients suffering from dysphagia.

Ethosomes loaded with lipophilic drugs, as NBV, can have two possible pathways of permeation through the skin; intradermal and transfollicular.Nanosized ethosomes (< 100 nm) can produce efficient intradermal and transfollicular reservoirs for sustained drug delivery.The formulated transdermal patch loaded with the optimized ethosomal dispersion (OED) showed enhanced bioavailability by 7.9 folds compared to Nevilob® oral tablets.

Formulation of novel niosomal repaglinide chewable tablets using coprocessed excipients: in vitro characterization, optimization and enhanced hypoglycemic activity in rats.

Repaglinide (RPG), a monotherapy insulin secretagogue used to treat diabetes mellitus-type II yet, it suffers from poor water solubility and variable bioavailability (∼ 50%) due to hepatic first pass metabolism. In this study, 2FI I-Optimal statistical design was employed to encapsulate RPG into niosomal formulations using cholesterol,span 60 and peceolTM. The optimized niosomal formulation (ONF) showed particle size 306.60 ± 84.00 nm, zeta potential -38.60 ± 1.20 mV, polydispersity index 0.48 ± 0.05 and entrapment efficiency 92.00 ± 2.60%. ONF showed > 65% RPG release that lasted for 3.5 h, and significantly higher sustained release compared to Novonorm® tablets after 6 h (p < 0.0001). TEM for ONF showed spherical vesicles with dark core and light-colored lipid bilayer membrane. RPG peaks disappeared in FTIR confirming successful RPG entrapment. To eliminate dysphagia associating conventional oral tablets, chewable tablets loaded with ONF were prepared using coprocessed excipients; Pharmaburst® 500, F-melt® and Prosolv® ODT. Tablets showed friability <1%, hardness 3.9 ± 0.423-4.7 ± 0.410 Kg, thickness 4.1 ± 0.045-4.4 ± 0.017 mm and acceptable weight.All tablets showed robust RPG release at 30 min compared to Novonorm® tablets. At 6h, chewable tablets containing only Pharmaburst® 500 and F-melt® showed sustained and significantly increased RPG release compared to Novonorm® tablets (p < 0.05). Pharmaburst® 500 and F-melt® tablets showed rapid in vivo hypoglycemic effect with 5 and 3.5 fold significant reduction in blood glucose compared to Novonorm® tablets (p < 0.05) at 30 min. Also, at 6h the same tablets showed 1.5 and 1.3 fold significant extended reduction in blood glucose compared to the same market product (p < 0.05). It could be concluded that chewable tablets loaded with RPG ONF represent promising novel oral drug delivery systems for diabetic patients suffering from dysphagia.

Olive Oil/Pluronic Oleogels for Skin Delivery of Quercetin: In Vitro Characterization and Ex Vivo Skin Permeability.

The main objective of this study was to prepare and characterize oleogel as potential carrier for quercetin skin delivery. The formulations were prepared by adding olive oil (5-30%) to Pluronic F127 hydrogel and were evaluated for particle size, zeta potential, viscosity in vitro quercetin release and stability, and were compared with that of Pluronic F127 hydrogel. The selected formulation was characterized for its interaction possibility, ex vivo skin permeation and skin histological changes and safety. The particle sizes ranged from 345.3 ± 5.3 nm to 401.5 ± 2.8 nm, and possessed negative charges. The viscosities of the formulations were found in the range of 6367-4823 cps with inverse proportionality to olive oil percentage while the higher percentages showed higher quercetin release. Percentages of 25% and 30% olive oil showed instability pattern under the conditions of accelerated stability studies. Differential scanning calorimetry verified the existence of quercetin in micellar aggregation and the network in the case of hydrogel and oleogel respectively. Ex vivo skin permeation showed an improved skin permeation of quercetin when 20% olive oil containing oleogel was used. Skin histology after 10 days of application showed stratum corneum disruption and good safety profile. Based on these findings, the proposed oleogel containing 20% olive oil denotes a potential carrier for topical delivery of quercetin.

Enhanced Transdermal Delivery of Bisoprolol Hemifumarate via Combined Effect of Iontophoresis and Chemical Enhancers: Ex Vivo Permeation/In Vivo Pharmacokinetic Studies.

Bisoprolol hemifumarate (BH) is an antihypertensive drug that is used as first-line treatment for chronic hypertension and angina pectoris. Our study was performed to enhance the transdermal delivery of BH, a hydrophilic drug active with high molecular weight, through differently prepared hydrogels. The synergistic effect of permeation enhancers and iontophoresis was investigated via both ex vivo and in vivo permeation studies. Ex vivo iontophoretic permeation studies were performed by using male albino Wistar rat skin. Cellosolve® hydrogel (F7) showed a 1.5-fold increase in Q180, Jss, and FER compared to F5 (lacking permeation enhancer). BH pharmacokinetic data were studied in human volunteers, following transdermal delivery of F7, using Phoresor® Unit II iontophoresis device, compared to conventional oral tablets. F7 showed 1.9- and 2-fold higher values of Cmax and AUC0-40, respectively compared to Concor® tablets, as well as a smaller Tmax (2.00 ± 2.00 h). The relative bioavailability of F7 was found to be 201.44%, relative to Concor® tablets, demonstrating the significantly enhanced transdermal permeation of BH from the selected hydrogel by iontophoresis, in human volunteers. Finally, results showed the successful utility of permeation enhancers combined with iontophoresis in significantly enhanced transdermal permeation of BH, despite its large molecular weight and hydrophilic nature. Therefore, this strategy could be employed as a successful alternative route of administration to conventional oral tablets.

Preparation of solid dispersion systems for enhanced dissolution of poorly water soluble diacerein: In-vitro evaluation, optimization and physiologically based pharmacokinetic modeling.

Diacerein (DCN), a BCS II compound, suffers from poor aqueous solubility and limited bioavailability. Solid dispersion systems (SD) of DCN were prepared by solvent evaporation, using hydrophilic polymers. In-vitro dissolution studies were performed and dissolution parameters were evaluated. I-Optimal factorial design was employed to study the effect of formulation variables (drug:polymer ratio and polymer type) on the measured responses including; drug content (DC) (%), dissolution efficiency at 15 min (DE (15 min)%) and 60 min (DE (60 min)%) and mean dissolution time (MDT) (min). The optimized SD was selected, prepared and evaluated, allowing 10.83 and 3.42 fold increase in DE (15 min)%, DE (60 min)%, respectively and 6.07 decrease in MDT, compared to plain drug. DSC, XRD analysis and SEM micrographs confirmed complete amorphization of DCN within the optimized SD. Physiologically based pharmacokinetic (PBPK) modeling was employed to predict PK parameters of DCN in middle aged healthy adults and geriatrics. Simcyp® software established in-vivo plasma concentration time curves of the optimized SD, compared to plain DCN. Relative bioavailability of the optimized SD compared to plain drug was 229.52% and 262.02% in healthy adults and geriatrics, respectively. Our study reports the utility of PBPK modeling for formulation development of BCS II APIs, via predicting their oral bio-performance.

Development of orally disintegrating tablets containing solid dispersion of a poorly soluble drug for enhanced dissolution: In-vitro optimization/in-vivo evaluation.

Diacerein (DCN), a potent anti-inflammatory API used to treat osteoarthritis yet, it suffers from poor water solubility which affects its oral absorption. Unabsorbed colonic DCN is converted into rhein, which is responsible for laxation as a main side effect of DCN treatment. Therefore, in this study orally disintegrating tablets (ODTs) loaded with optimized DCN solid dispersion system were prepared using different co-processed excipients (Prosolv® ODT, Pharmaburst® 500 and F-melt®), aiming to achieve improved solubility, rapid absorption and consequently limited amount of rhein reaching the colon. Prepared ODTs were evaluated for physical characteristics, in-vitro drug release, disintegration and wetting times. Dissolution parameters; dissolution efficiency percent at 10 (DE (10 min)%) and 30 (DE (30 min)%) min and mean dissolution time (MDT) were determined. The optimized ODT showed 1.50 and 1.12 fold increase in DE (10 min)% and DE (30 min)%, respectively and 2 fold decrease in MDT, compared to Diacerein® capsules. In-vivo anti-inflammatory effect of optimized ODT, using rat paw edema revealed significant increase in edema inhibition (p < 0.0465) and promoted onset of action compared to Diacerein® capsules at 0.5 hr. It could be concluded that optimized ODT could be promising for enhanced dissolution and rapid absorption of DCN from the oral cavity.

Novel instantly-dispersible nanocarrier powder system (IDNPs) for intranasal delivery of dapoxetine hydrochloride: in-vitro optimization, ex-vivo permeation studies, and in-vivo evaluation.

Dapoxetine (D) suffers from poor oral bioavailability (42%) due to extensive metabolism in the liver. The aim of this study was to enhance the bioavailability of D via preparing instantly-dispersible nanocarrier powder system (IDNPs) for intranasal delivery of D. IDNPs were prepared using the thin film hydration technique, followed by freeze-drying to obtain easily reconstituted powder providing rapid and ready method of administration. The produced nanocarrier systems were evaluated for drug content, entrapment efficiency percentage, particle size, polydispersity index, zeta potential, and drug payload. The optimized nanocarrier system was morphologically evaluated via transmission electron microscopy and the optimized freeze-dried IDNPs were evaluated for ex-vivo permeation and in-vivo pharmacokinetic studies in rabbits following intranasal and oral administration. The relative bioavailability of D after intranasal administration of freeze-dried IDNPs was about 235.41% compared to its corresponding oral nanocarrier formulation. The enhanced D permeation and improved bioavailability suggest that IDNPs could be a promising model for intranasal delivery of drugs suffering from hepatic first pass effect.

Novel instantly-soluble transmucosal matrix (ISTM) using dual mechanism solubilizer for sublingual and nasal delivery of dapoxetine hydrochloride: In-vitro/in-vivo evaluation.

Dapoxetine (D) suffers from poor oral bioavailability (42%) due to extensive first pass metabolism. The usefulness of transmucosal (sublingual and intranasal) drug delivery to improve bioavailability of D, a weak basic drug, has been hampered by its poor solubility in the neutral pH of the body fluids. In this study, instantly-soluble transmucosal matrices (ISTMs) of D, containing dual mechanism solubilizer (Pluronic F-127/citric acid mixture), were prepared by lyophilization technique to enhance matrix disintegration, dissolution and transmucosal permeation. The matrices were evaluated for in-vitro disintegration, wetting time, in-vitro dissolution, ex vivo transmucosal permeation, scanning electron microscopy and in-vivo studies. Dissolution studies confirmed the higher ability of ISTMs to enhance the early time point dissolution and maintain complete drug dissolution in pH 6.8 compared to conventional lyophilized matrices. The optimized ISTM gave approximately 77.54 and 88.40 folds increase of D dissolution after 1 and 3min relative to the drug powder in pH 6.8. ISTMs containing the highest F127 concentration (2%) and the lowest gelatin and mannitol concentrations (1%) exhibited the shortest in-vitro disintegration times (<10s), the fastest dissolution in the neutral pH of body fluids (∼99% in 3min) and the highest enhancement of transmucosal permeation. The relative bioavailabilities of D after sublingual and intranasal administration of ISTMs to rabbits were about 124.58% and 611.15%, respectively, in comparison to the oral market tablet. The significant increase of drug dissolution in nasal fluids, rapid permeation rate together with the improved bioavailability propose that ISTMs could be promising for intranasal delivery of drugs suffering from oral hepatic metabolism and have limited solubility in nasal fluids.

Microemulsion and poloxamer microemulsion-based gel for sustained transdermal delivery of diclofenac epolamine using in-skin drug depot: in vitro/in vivo evaluation.

Microemulsion (ME) and poloxamer microemulsion-based gel (PMBG) were developed and optimized to enhance transport of diclofenac epolamine (DE) into the skin forming in-skin drug depot for sustained transdermal delivery of drug. D-optimal mixture experimental design was applied to optimize ME that contains maximum amount of oil, minimum globule size and optimum drug solubility. Three formulation variables; the oil phase X1 (Capryol(®)), Smix X2 (a mixture of Labrasol(®)/Transcutol(®), 1:2 w/w) and water X3 were included in the design. The systems were assessed for drug solubility, globule size and light absorbance. Following optimization, the values of formulation components (X1, X2, and X3) were 30%, 50% and 20%, respectively. The optimized ME and PMBG were assessed for pH, drug content, skin irritation, stability studies and ex vivo transport in rat skin. Contrary to PMBG and Flector(®) gel, the optimized ME showed the highest cumulative amount of DE permeated after 8h and the in vivo anti-inflammatory efficacy in rat paw edema was sustained to 12h after removal of ME applied to the skin confirming the formation of in-skin drug depot. Our results proposed that topical ME formulation, containing higher fraction of oil solubilized drug, could be promising for sustained transdermal delivery of drug.