Darifenacin Self-assembled Liquid Crystal Cubic Nanoparticles: a Sustained Release Approach for an Overnight Control of Overactive Bladder.

The current study is regarding the development and characterization of Darifenacin-loaded self-assembled liquid crystal cubic nanoparticles (LCCN). An anhydrous approach was used for the preparation of these cubic nanoparticles using a hydrotropic agent (propylene glycol), with minimal energy input. Upon dispersion in aqueous medium, the system was successfully transformed to cubosomal nanoparticles counterpart as depicted by transmission electron micrographs. A Box-Behnken design was used to optimize formulation variables, namely A: amount of GMO, B: amount of Pluronic F127, C: amount of PG, and D: amount of HPMC. The design has generated 29 formulae which were tested regarding drug content uniformity, dispersibility in water, particle size, zeta potential, polydispersity index, and in vitro release behavior. The numerical optimization algorithms have generated an optimized formula with high desirability ≈ 1. The optimized formula displayed small particle size, good homogeneity, and zeta potential along with controlled in vitro release profile and ex vivo permeation through rabbit intestine. Thus, self-assembled LCCN might offer an alternative anhydrous approach for the preparation of cubosomal nanoparticles with controlled release profile for a possibly better control of overactive bladder syndrome which tremendously affect the overall life quality.

The potential of intranasal delivery of nanocrystals in powder form on the improvement of zaleplon performance: in-vitro, in-vivo assessment.

OBJECTIVE: The present work focuses on improving zaleplon (ZAP) performance through nanosizing its insoluble particles which were then delivered intranasally in powder form. SIGNIFICANCE: Since nanopowders have an exceptional ability to cross cell membrane, their absorption is facilitated in the solid form. Hence, delivering insoluble ZAP nanocrystals (NC) through intranasal route improves its bioavailability due to both nanosization and the escape of hepatic metabolism. METHODS: Nanocrystals were prepared by anti-solvent precipitation followed by probe sonication in presence of Soluplus®, Poloxamer-188 (0.25%), sodium lauryl sulfate (0.5%), and mannitol. Physicochemical evaluation of the prepared NC was done by DSC and XRPD. TGA was performed for stability detection. Ex vivo permeation study through isolated cattle nasal mucosal membrane, in addition to an in vivo bioavailability study was performed for assessment of the prepared NC. RESULTS: Nanosization to 200 nm contributed to the enhancement in dissolution ∼100% within 30 min and reduced half-life to 1.63 min. Confirmation of adsorption of polymers over NC' surface was elucidated. TGA confirmed their thermal stability. Ex vivo permeation study showed a 2.7 enhancement ratio in favor of the prepared NC. Both the extent and rate of NC absorption through nasal mucosa of rabbits were significantly higher (p Ë‚ .05) than in case of oral tablets. The relative bioavailability of NC was increased 3.14 times as compared to the Sleep aid® tablets. CONCLUSION: The intranasal delivery of nanoscale ZAP powder proved to be a successful alternative to oral formulations that suffer poor absorption and limited bioavailability.

Chronological Delivery of Antihypertensive Drugs in Bilayered Core-in-Cup Buccoadhesive Tablets: In Vitro and In Vivo Evaluation.

Hypertension shows circadian blood pressure rhythms (day-night pattern) that urge the delivery of antihypertensive drugs at the right time in the desired levels. Thus, a bilayered core-in-cup buccoadhesive tablet was formulated that immediately releases olmesartan, to give a burst effect, and controls azelnidipine release, to prolong its therapeutic effect. The main challenge was the poor bioavailability of azelnidipine due to its poor aqueous solubility and first-pass effect. Hence, liquisolid compact buccoadhesive tablets were prepared to enhance solubility, dissolution profiles, and bypass the oral route. Two factorial designs were conducted to study the type and concentration effect of the mucoadhesive polymers on the dissolution and mucoadhesion of olmesartan and azelnidipine. Characterization studies were conducted regarding drug content, surface pH, water uptake, mucoadhesive strength, in vitro release, and ex vivo permeability. The core-in-cup olmesartan/azelnidipine buccoadhesive tablet showed similar release profile to the statistically optimized formulae of each drug. In vitro dissolution study showed enhanced release of azelnidipine than the directly compressed tablets, to comply with the regulatory standards of controlled release systems. In vivo pharmacokinetic study of olmesartan and azelnidipine conducted on human volunteers against Rezaltas® 10/8 mg tablet showed percentage relative bioavailability of 106.12 and 470.82%, respectively. Graphical Abstract.

Facile development, characterization, and optimization of new metformin-loaded nanocarrier system for efficient colon cancer adjunct therapy.

PURPOSE: Metformin hydrochloride (MF) repurposing as adjuvant anticancer therapy for colorectal cancer (CRC) proved effective. Several studies attempted to develop MF-loaded nanoparticles (NPs), however the entrapment efficiency (EE%) was poor. Thus, the present study aimed at the facile development of a new series of chitosan (CS)-based semi-interpenetrating network (semi-IPN) NPs incorporating Pluronic® nanomicelles as nanocarriers for enhanced entrapment and sustained release of MF for efficient treatment of CRC. METHODS: The NPs were prepared by ionic gelation and subsequently characterized using FTIR, DSC, TEM, and DLS. A full factorial design was also adopted to study the effect of various formulation variables on EE%, particle size, and zeta-potential of NPs. RESULTS: NPs had a spherical shape and a mean particle size ranging between 135 and 220 nm. FTIR and DSC studies results were indicative of successful ionic gelation with the drug being dispersed in its amorphous form within CS-Pluronic® matrix. Maximum EE% reaching 57.00 ± 12.90% was achieved using Pluronic®-123 based NPs. NPs exhibited a sustained release profile over 48 h. The MF-loaded NPs sensitized RKO CRC cells relative to drug alone. CONCLUSION: The reported results highlighted the novel utility of the developed NPs in the arena of colon cancer treatment.

Zero-order release and bioavailability enhancement of poorly water soluble Vinpocetine from self-nanoemulsifying osmotic pump tablet.

Solid self-nanoemulsifying (S-SNEDDS) asymmetrically coated osmotic tablets of the poorly water-soluble drug Vinpocetine (VNP) were designed. The aim was to control the release of VNP by the osmotic technology taking advantage of the solubility and bioavailability-enhancing capacity of S-SNEDDS. Liquid SNEDDS loaded with 2.5 mg VNP composed of Maisine™ 35-1, Transcutol® HP, and Cremophor® EL was adsorbed on the solid carrier Aeroperl®. S-SNEDDS was mixed with the osmotic tablet excipients (sodium chloride, Avicel®, HPMC-K4M, PVP-K30, and Lubripharm®), then directly compressed to form the core tablet. The tablets were dip coated and mechanically drilled. A 32*21 full factorial design was adopted. The independent variables were: type of coating material (X1), concentration of coating solution (X2), and number of drills (X3). The dependent variables included % release at 2 h (Y1), at 4 h (Y2), and at 8 h (Y3). The in vivo performance of the optimum formula was assessed in rabbits. Zero-order VNP release was obtained by the single drilled 1.5% Opadry® CA coated osmotic tablets and twofold increase in VNP bioavailability was achieved. The combination of SNEDDS and osmotic pump tablet system was successful in enhancing the solubility and absorption of VNP as well as controlling its release.

Effect of formulation variables on design, in vitro evaluation of valsartan SNEDDS and estimation of its antioxidant effect in adrenaline-induced acute myocardial infarction in rats.

Valsartan is a specific angiotensin II antagonist used for the treatment of hypertension. It suffers from low aqueous solubility and high variability in its absorption after oral administration. The aim of this study was to improve the dissolution and thereby the bioavailability of Valsartan through the development of self nano-emulsifying drug delivery systems. Four ternary phase diagrams were constructed to identify the self-emulsification region of Capmul® MCM, Labrafil® M1944, Capryol™ 90 and Labrafac® PG together with Cremophore® RH 40 and Transcutol™ HP as oil, surfactant and co-surfactant, respectively. The effect of oil type, oil and surfactant concentration on droplet size and in vitro Valsartan dissolution were studied. The protective effect of the optimum formula F5 in adrenaline-induced oxidative stress in rats during myocardial infarction was determined. Formula F5 exhibited globule size of (13.95 nm) with 76.07% ± 1.10 of Valsartan dissolved after five minutes compared to Disartan 80 mg capsules (13.43%). Results revealed a significant reduction (p < 0.05) in serum aspartate transaminase, creatine kinase myocardial band and malondialdehyde levels, while a significant increase (p < 0.05) in serum glutathione in F5. Therefore, self nano-emulsifying drug delivery systems could be considered as a promising approach to improve the dissolution and thereby the bioavailability of Valsartan.

Multiplexed integrating plasmids for engineering of the erythromycin gene cluster for expression in Streptomyces spp. and combinatorial biosynthesis.

Bacteria in the genus Streptomyces and its close relatives are prolific producers of secondary metabolites with antibiotic activity. Genome sequencing of these bacteria has revealed a rich source of potentially new antibiotic pathways, whose products have never been observed. Moreover, these new pathways can provide novel genes that could be used in combinatorial biosynthesis approaches to generate unnatural analogues of existing antibiotics. We explore here the use of multiple orthologous integrating plasmid systems, based on the int/attP loci from phages TG1, SV1, and ϕBT1, to express the polyketide synthase (PKS) for erythromycin in a heterologous Streptomyces host. Streptomyces strains containing the three polyketide synthase genes eryAI, eryAII, and eryAIII expressed from three different integrated plasmids produced the aglycone intermediate, 6-deoxyerythronolide B (6-dEB). A further pair of integrating plasmids, both derived from the ϕC31 int/attP locus, were constructed carrying a gene cassette for glycosylation of the aglycone intermediates, with or without the tailoring gene, eryF, required for the synthesis of erythronolide B (EB). Liquid chromatography-mass spectrometry of the metabolites indicated the production of angolosaminyl-6-dEB and angolosaminyl-EB. The advantages of using multiplexed integrating plasmids for engineering expression and for combinatorial biosynthesis were demonstrated.

Novel mucoadhesive celecoxib-loaded cubosomal sponges: Anticancer potential and regulation of myeloid-derived suppressor cells in oral squamous cell carcinoma.

Oral squamous-cell carcinoma (OSCC) is a widespread health problem. Myeloid-derived suppressor cells (MDSCs) are major tumor microenvironment (TME) population that govern many carcinogenesis aspects by establishing immunosuppressive milieu favoring tumor aggressiveness and treatment resistance. Cyclooxygenase-2 (COX-2) regulates MDSCs activity, hence, COX-2-selective inhibition by celecoxib (CXB) showed good anticancer effect at relatively high doses with possible subsequent cardiovascular complications. Therefore, targeted CXB delivery to MDSCs may represent a promising OSCC treatment strategy. Novel mucoadhesive-cubosomal buccal sponges were prepared for MDSCs targeting and were evaluated for their in-vitro quality attributes, ex-vivo mucoadhesion using buccal chicken-mucosa. Optimally-selected formulation showed considerable uptake by CD33+/11b+MDSCs in human OSCC cell-line (SCC-4) when quantitatively analyzed by flow-cytometry and examined using confocal-laser microscope. Optimum formulations loaded with low CXB doses (12 mg) were promoted to in-vivo studies via local application, using 4-nitroquinoline-1-oxide-induced OSCC in rats, and compared to their corresponding CXB gels. SP16 revealed the highest ability to decrease MDSC activation, recruitment and TME-immunosuppression in the isolated tumors. Consequently, SP16 exerted the greatest capacity to reduce histologic tumor grade, the OSCC-specific serum tumor markers levels, cancer hallmarks and stemness markers. CXB-loaded cubosomal sponges preferentially target MDSCs with noticeable anticancer potential and may exemplify novel mucoadhesive nanocarriers for OSCC treatment.

Effective loading of incompatible drugs into nanosized vesicles: a strategy to allow concurrent administration of furosemide and midazolam in simulated clinical settings.

The current study aims to assess the use of nanocarriers to limit drug incompatibilities in clinical settings, and thus eliminating serious clinical consequences (e.g., catheter obstruction and embolism), and enhancing in vivo bioavailability and efficacy. As a proof-of-concept, the impact of loading well-documented physically incompatible drugs (i.e., furosemide and midazolam) into nanosized vesicles on in vitro stability and in vivo bioavailability of the two drugs was investigated. Furosemide and midazolam were loaded into nanosized spherical vesicles at high entrapment efficiency (ca. 62-69%). The drug-loaded vesicles demonstrated a sustained drug release patterns, high physical stability and negligible hemolytic activity. Physical incompatibility was assessed by exploiting microscopic technique coupled with image processing and analysis, dynamic light scattering and laser Doppler anemometry. Incorporation of drugs separately inside the nanosized vesicles dramatically decreased size and number of the precipitated particles. In vivo, the niosomal drug mixture demonstrated a significant improvement in pharmacokinetic profiles of furosemide and midazolam compared to the mixed free drug solutions, as evidenced by their longer circulation half-lives and higher area under the plasma-concentration time curves of both drugs. Nanocarriers could provide an auspicious strategy for circumventing drug incompatibilities, thus reducing adverse reactions, hospitalization period and improving therapeutic outcomes.

Floating tablet of trimetazidine dihydrochloride: an approach for extended release with zero-order kinetics.

Trimetazidine dihydrochloride is an effective anti-anginal agent; however, it is freely soluble in water and suffers from a relatively short half-life. To solve this encumbrance, it is a prospective candidate for fabricating trimetazidine extended-release formulations. Trimetazidine extended-release floating tablets were prepared using different hydrophilic matrix forming polymers including HPMC 4000 cps, carbopol 971P, polycarbophil, and guar gum. The tablets were fabricated by dry coating technique. In vitro evaluation of the prepared tablets was performed by the determination of the hardness, friability, content uniformity, and weight variation. The floating lag time and floating duration were also evaluated. Release profile of the prepared tablets was performed and analyzed. Furthermore, a stability study of the floating tablets was carried out at three different temperatures over 12 weeks. Finally, in vivo bioavailability study was done on human volunteers. All tablet formulas achieved < 0.5 min of floating lag time, more than 12 h of floating duration, and extended t (1/2). The drug release in all formulas followed zero-order kinetics. T4 and T8 tablets contained the least polymer concentration and complied with the dissolution requirements for controlled-release dosage forms. These two formulas were selected for further stability studies. T8 exhibited longer expiration date and was chosen for in vivo studies. T8 floating tablets showed an improvement in the drug bioavailability compared to immediate-release tablets (Vastrel® 20 mg).

Effect of formulation design and freeze-drying on properties of fluconazole multilamellar liposomes.

Fluconazole-entrapped multilamellar liposomes were prepared using the thin-film hydration method. The effects of cholesterol molar ratio, charge-inducing agents, and α-tocopherol acetate on encapsulation efficiency values and in vitro drug release of multilamellar liposomes were studied. Freeze-dried liposomal products were prepared with or without cryoprotectants. Results showed that incorporation of stearylamine resulted in an increased entrapment of fluconazole, whereas incorporation of dicetyl phosphate decreased the drug entrapment efficiency. The incorporation of α-tocopherol acetate into fluconazole multilamellar liposomes resulted in the increase of entrapment efficiency of fluconazole liposomes. In vitro release studies revealed that incorporation of cholesterol into multilamellar liposomal formulations decreased drug permeability from formulations. Positively charged fluconazole multilamellar liposomes gave rise to a slow release rate compared to neutral liposomes whereas negatively charged fluconazole liposomes showed a rapid release rate. Physical stability studies showed that lyophilized cake of liposomes without cryoprotectants was compact and difficult to reconstitute compared to fluffy easily reconstituted cakes upon using cryoprotectants. Fluconazole retained in freeze-dried liposomes without cryoprotectants was 63.452% compared to 91.877% using three grams of trehalose as a cryoprotectant per gram lipid in positively charged multilamellar liposomes. Physical stability studies showed superior potentials of the lyophilized product after reconstitution in comparison with those of a solution product.

Integrated nanovesicular/self-nanoemulsifying system (INV/SNES) for enhanced dual ocular drug delivery: statistical optimization, in vitro and in vivo evaluation.

Ocular drug administration is usually problematic and suffers low bioavailability due to several physiological and biological factors that hinder their effective treatment. Terconazole (TZ) is considered as one of the effective ocular antifungal agents that is usually administrated intravitreally for higher efficacy. The aim of the work in this study is to formulate a TZ-loaded ocular drug delivery system with high efficiency and good tolerability. First, TZ-loaded bile-based nanovesicles (BBNV) were prepared and the formulation variables (namely, Span 60, cholesterol, and sodium deoxycholate levels) were optimized based on the results of the entrapment efficiency (EE%), particle size (PS), and zeta potential (ZP) using Box-Behnken statistical design. The optimized system was formulated using 73.59 mg Span 60, 1.28 mg cholesterol, and 3.11 mg sodium deoxycholate. The formulated system showed vesicles with PS of 526 nm, - 42.2 mV ZP, and 93.86% EE%. TZ release, cellular uptake, and cytotoxicity of the optimized system were evaluated in vitro. In addition, in vivo assessment of its safety was conducted histopathologically and via ocular irritation test to ensure the ocular tolerance of the system. Afterwards, the optimized TZ-loaded BBNV was integrated into a self-nanoemulsifying system (SNES) to allow faster TZ release for immediate antifungal effect, enhanced ocular residence, and improved ocular permeation. TZ release study revealed more than 2 folds increment in drug release rate from the integrated system compared to BBNV alone. Finally, this integrated system was assessed for its antifungal activity in vivo where it demonstrated higher antifungal activity against induced Candida albicans infection. Graphical abstract.

Colon targeting of celecoxib nanomixed micelles using pulsatile drug delivery systems for the prevention of inflammatory bowel disease.

Inflammatory bowel disease (IBD) is a debilitating condition characterized by chronic inflammation of the colon which can increase the risk of colon cancer. Celecoxib (CXB), a cyclooxygenase-2 inhibitor, showed potential for the prophylaxis against IBD. However, it suffers from poor aqueous solubility and cardiovascular toxicity on prolonged use. Here, CXB solubility was enhanced using nanomixed micelles (NMMs) and then colon targeted in a pulsatile system to minimize systemic side effects. Pluronic P123 NMMs with bile salts or hydrophilic Pluronics were prepared using the thin film hydration technique. NMMs were characterized for particle size, size distribution and zeta potential before and after freeze drying and for solubility enhancement. The freeze dried NMMs were then loaded in pulsatile systems with varying tablet plugs containing time-dependent polymers at different concentrations. The optimum NMM consisted of Pluronic P123 and sodium taurocholate (1:1) and CXB:surfactant mixture ratio of 1:30. The pulsatile capsules, containing a tablet plug made of 75% Carbopol®, achieved the target release profile with 88.35% of the dose released after an 8 hrs lag period. Finally, the optimum NMM/pulsatile system showed protective effect against experimentally-induced colitis compared to conventional capsules and pulsatile capsules filled with pure CXB.

A New Crystal Engineering Technique for Dissolution Enhancement of Poorly Soluble Drugs Combining Quasi-emulsion and Crystallo-co Agglomeration Methods.

A target of best dissolution improvement of poorly soluble drugs is a necessity for the success of formulation in industry. The present work describes the preparation, optimization, and evaluation of a new spherical agglomeration technique for glimepiride as a model of poorly soluble drugs. It involved the emulsification of a drug solution containing a dispersed carrier that tailors the crystal habit of the drug to a perfect spherical geometry, in a poor solvent containing a hydrophilic polymer which imparts sphericity and strength to the formed agglomerates. The FTIR peaks of optimized product did not show any sign of chemical interaction between the drug and adsorbed carrier. The DSC and X ray diffractogram showed a peak characteristic of spherical agglomerates with much less intensity than that of glimepiride. The dissolution t1/2 of the drug slightly decreased from 381 min to 334 min in plain agglomerates. Introducing polymers in the aqueous phase of emulsion led to an improvement in the dissolution, reflected in t1/2 ranging from 118 to 231 min. Agglomerates prepared with Starlac/PVP demonstrated the most optimum physicochemical characteristics being spherical, with the best flowability and packability parameters. The t1/2 was as short as 19 min. The new carrier/polymer system offered a synergistic combination that highly contributed in dissolution enhancement of glimepiride. The spheronization and amorphisation offered by the new technique could account for such improvement.

Coated Lipidic Nanoparticles as a New Strategy for Enhancing Nose-to-Brain Delivery of a Hydrophilic Drug Molecule.

Oral Almotriptan maleate (ALM) is used in the treatment of migraine; however, due to its extreme aqueous solubility, shows poor penetration and lesser concentration in the brain thus requiring frequent oral dosing. Being flexible and lipophilic in nature, nanostructured lipid carriers (NLCs) represent a promising tool in delivering therapeutic substances to the brain. This investigation is meant to explore the capability of mucoadhesive chitosan-coated NLCs to efficiently deliver ALM to the brain through the nasal route as a non-invasive alternative route for targeting the central nervous system (CNS). D-optimal design was adopted and thirteen different formulae were prepared using hot homogenization and ultrasonication technique; where an accurate amount of the almotriptan was added to the molten lipid mixture followed by the addition of the heated aqueous phase under stirring, then the mixture was subjected to homogenization and ultrasonication. The prepared systems were then assessed for their particle size, PDI (polydispersity index), zeta potential (ZP), and entrapment efficiency (EE). The optimized selected formula; F1; composed of 50/50 Compritol/Labrafil and a co-mixture of 2:1 tween 80: Lauroglycol all coated in chitosan, showed a PS of 255 nm, PDI 0.27, ZP 34.1 mV, and 80% EE. A bi-phasic in vitro drug release pattern was obtained, enhanced mucoadhesive property and ex-vivo permeability through sheep nasal mucosa were attained. The In vivo studies performed on albino rabbits showed significantly higher Cmax results in plasma of the optimized ALM-NLC (1.54 µg/mL) compared to those of IN ALM solution (0.25 µg/mL) and ALM oral tablet market product (0.58 µg/mL). Brain Cmax were found to be 3.64 µg/mL, 0.5 µg/mL and 0.48 µg/mL for IN ALM-NLC, oral ALM market product and, IN ALM solution, respectively. Histopathological examination marked the formula as safe.

Fluconazole mucoadhesive buccal films: in vitro/in vivo performance.

Fluconazole mucoadhesive buccal films were prepared using film forming polymers namely; hydroxypropyl methyl cellulose (HPMC), hydroxyethyl cellulose (HEC), chitosan, Eudragit and sodium alginate (SALG) either alone or in combination with bioadhesive polymers. The bioadhesive polymers studied were sodium carboxymethyl cellulose (SCMC), Carbopol 974P, and polycarbophil (AA-A). The prepared films were characterized by means of film thickness, surface pH, swelling capacity, in vitro adhesion, in vivo residence time, in vitro drug release and in vivo drug release to determine the amount of drug release from selected film formulae using microbiological assay and HPLC. Optimum release behavior, convenient bioadhesion, acceptable elasticity were exhibited by film containing 2% HPMC and 1% SCMC (fresh or stored for 6 months). Determination of the amount of drug released in saliva after application of the selected fluconazole films confirmed the ability of the film to deliver the drug over a period of approximately 300 minutes and to reduce side effects and possibility of drug interaction encountered during systemic therapy of fluconazole, which would be beneficial in the case of oral candidiasis.

Core-in-cup/liquisol dual tackling effect on azelnidipine buccoadhesive tablet micromeritics, in vitro release, and mucoadhesive strength.

Reduced bioavailability of azelnidipine is related to its poor aqueous solubility and extensive first-pass metabolism, which hinder its efficacy. These problems were addressed by implementing (1) a liquisol technique for promoting the dissolution rate in a controlled-release manner and (2) a core-in-cup bucco-adhesive drug delivery system as an alternative to the oral route. A 33 factorial design was used to study the effects of polymer type (sodium carboxymethyl cellulose (CMC Na), chitosan, or Carbomer P940) concentration (5, 10 or 15 %) and preparation technique (simple mix, liquisol or wet granulation) on the dissolution and mucoadhesion of core-in-cup azelnidipine buccoadhesive tablets. Tablet micromeritics, swelling index, mucoadhesive strength and in vitro release were characterized. Statistical analyses of these factors show ed significant effects on the studied responses, where F#16 prepared by the liquisol technique and containing 15 % CMC Na was chosen with an overall desirability of 0.953.

Superhydrophobic Substrates for Ultrahigh Encapsulation of Hydrophilic Drug into Controlled-Release Polyelectrolyte Complex Beads: Statistical Optimization and In Vivo Evaluation.

: In this work, ultrahigh drug-loaded chitosan (Ch)/K-carrageenan (Kc) polyelectrolyte complex (PEC) beads were formed in situ by cross-linking in a glutaraldehyde-saturated atmosphere and were prepared on superhydrophobic substrates fabricated by spraying glass surfaces with ready-made spray for domestic use (NeverWet®). Verapamil hydrochloride (VP), a highly hydrophilic drug with a short biological half-life, was incorporated into a series of Ch-based and/or Ch/Kc-PEC-based beads to control its release profile in vivo. The formulation of VP-loaded beads was optimized using stepwise statistical designs based on a prespecified criterion. Several characteristics of the prepared beads, such as entrapment efficiency (EE%), in vitro drug release, swelling ratio, size and surface microstructure as well as molecular interactions between the drug and formulation ingredients, were investigated. In vivo pharmacokinetic (PK) studies were carried out using the rabbit model to study the ability of the optimized VP-loaded beads to control the absorption rate of VP. Results revealed that the prepared superhydrophobic substrates were able to fabricate VP-loaded beads with extremely high EE exceeding 90% w/w compared to only 27.80% when using conventional ionotropic gelation technique. PK results showed that the rate of VP absorption was well controlled following oral administration of the optimized beads to six rabbits compared to a marketed VP immediate release (IR) tablet, as evidenced by a 2.2-fold increase in mean residence time (MRT) and 5.24-fold extension in half value duration (HVD) over the marketed product without any observed reduction in the relative oral bioavailability.

Design and in vitro/in vivo evaluation of novel mucoadhesive buccal discs of an antifungal drug: relationship between swelling, erosion, and drug release.

Two groups of fluconazole mucoadhesive buccal discs were prepared: (a) Fluconazole buccal discs prepared by direct compression containing bioadhesive polymers, namely, Carbopol 974p (Cp), sodium carboxymethyl cellulose (SCMC), or sodium alginate (SALG) in combination with hydroxypropyl methylcellulose (HPMC) or hydroxyethyl cellulose (HEC). (b) Fluconazole buccal discs prepared by freeze drying containing different polymer combinations (SCMC/HPMC, Cp/HPMC, SALG/HPMC, and chitosan/SALG). The prepared discs were evaluated by investigating their release pattern, swelling capacity, mucoadhesion properties, and in vitro adhesion time. In vivo evaluation of the buccal disc and in vivo residence times were also performed. Fluconazole salivary concentration after application of fluconazole buccal systems to four healthy volunteers was determined using microbiological assay and high-performance liquid chromatography. SCMC/HPMC buccal disc prepared by direct compression could be considered comparatively superior mucoadhesive disc regarding its in vitro adhesion time, in vivo residence time, and in vitro/in vivo release rates of the drug. Determination of the amount of drug released in saliva after application of the selected fluconazole disc confirmed the ability of the disc to deliver the drug over a period of approximately 5 h and to reduce side effects and possibility of drug interaction encountered during systemic therapy of fluconazole, which would be beneficial in the case of oral candidiasis.

Gastroretentive raft liquid delivery system as a new approach to release extension for carrier-mediated drug.

Gabapentin (GBP), an antiepileptic and anti-neuropathic agent, suffers from short half-life (5-7 h), has narrow absorption window, and is absorbed via carrier-mediated mechanism resulting in frequent dosing, poor compliance, and poor bioavailability (<60%). Moreover, GBP is a freely water-soluble drug, thus it is considered a challenging candidate to be formulated as extended release dosage form. In this study, raft forming systems were investigated as a potential drug delivery system for prolonging gastric residence time of GBP. A 23 full factorial design was adopted to study the effect of formulation variables (% gellan gum, % GMO, and % LM-pectin 101), on the percent of GBP released at different time intervals (1, 5, and 8 h) as well as the gel strength, and thus was achieved an optimized formula with zero-order release profile suitable for once-daily administration. In vivo assessment was performed in rats to evaluate gastric residence of the gel formed. In addition, the oral bioavailability of GBP relative to commercially available Neurontin® immediate release oral solution was also investigated. Significant increase was observed for Cmax, AUC(0-t), and AUC(0-∞). The increase in relative bioavailability of GBP from the optimized formula was 1.7 folds.