Ketorolac tromethamine floating beads for oral application: Characterization and in vitro/in vivo evaluation

The floating beads have been employed to make a sustained release of the drug in the stomach and to decrease the dose of the drug and hence overcome its side effects. The common benefits of the floating beads were it is easy preparation, without the need of a high temperature, and high percentage of the drug entrapment. In the present work, the Ketorolac tromethamine (KT) floating beads were prepared by extrusion congealing method utilizing calcium carbonate as a gas forming agent. The physical characters of the produced beads were investigated such as KT yield, KT loading, and entrapment efficiency of the drug. In addition, floating behavior, swelling, particle size, morphology and KT stability were also evaluated. In vitro drug release study was carried out, and the kinetics of the release was evaluated using the linear regression method. Furthermore, the in vivo analgesic effect of KT after oral administration of the selected formula of floating beads (F10) was carried out using hot plate and tail flick methods. Oral commercial KT tablets and KT solution were used for the comparison. The prepared beads remained floated for more than 8 h. The optimized formulation (F10) exhibited prolonged drug release (more than 8 h) and the drug release follows the Higuchi kinetic model, with a Fickian diffusion mechanism according to Korsmeyer-Peppas (n = 0.466). Moreover, F10 showed a sustained analgesic effect as compared to the commercial tablet.     

Formulation,in vitro,and in vivo evaluation of matrix-type transdermal patches containing olanzapine

Transdermal patches of olanzapine were aimed to be prepared to overcome the side effects by oral application. The strategy was formulation of eudragit-based polymeric films to prepare transdermal patches by using nonionic (span-20), anionic (sodium lauryl sulfate), cationic surfactant (benzalkonium chloride), and vegetable oil (olive oil) as permeation enhancers. The patches were subjected to physicochemical, in vitro release and ex vivo permeation studies. On the basis of in vitro release performance, ERL 100:ERS 100 in the ratio of 3:2 was selected for incorporation of permeation enhancers. The permeation studies showed that formulation containing 10% span 20 (OD3) exhibited greatest cumulative amount of drug permeated (19.02?±?0.21?mg) in 72?h, so OD3 was concluded as optimized formulation and assessed for pharmacokinetic, pharmacodynamic, and skin irritation potential. In vivo studies of optimized olanzapine patch in rabbit model revealed prolongation of action with F_rel 116.09% during 72-h study period. Neuroleptic efficacy of transdermal patch was comparable to oral formulation during rotarod and grip test in Wistar albino rats with no skin irritation. Thus, developed formulation of olanzapine is expected to improve the patient compliance, form better dosage regimen, and provide maintenance therapy to psychotic patients.     

含天然乳化剂的盐酸小檗碱自微乳的制备与体内外性能评价

目的:制备含阿拉伯胶的盐酸小檗碱自微乳,考察其体内外性能。方法:以天然乳化剂阿拉伯胶部分代替合成非离子型乳化剂聚山梨酯80制备盐酸小檗碱自微乳;评价两种自微乳的自乳化速率、微乳形态、粒径分布和释放度;采用大鼠在体单向肠灌流模型对两种自微乳的吸收动力学进行体内评价。结果:与合成乳化剂自微乳相比,天然乳化剂自微乳的自乳化速率基本相同,微乳乳滴粒径及粒径分布范围有所变大,体外释放速度略有降低,对盐酸小檗碱在大鼠在体肠吸收的促进效果更好。结论:用天然乳化剂阿拉伯胶部分代替合成乳化剂所制备的盐酸小檗碱自微乳可保持自微乳原有的体内外行为。     

Preparation and in vitro/in vivo evaluation of revaprazan hydrochloride nanosuspension

Revaprazan hydrochloride (RH) is a new reversible proton pump inhibitor. However, due to poor water solubility, oral bioavailability of the drug was relatively low. To investigate the particle size reduction effect of RH on dissolution and absorption, three suspensions that containing different sized particles were prepared by high pressure homogenization and in vitro/in vivo evaluations were carried out. DSC and powder X-ray diffraction were used to study crystalline state of freeze dried powder of RH suspensions and the results showed that particles of RH microsuspension and nanosuspension remained in the same crystalline state as coarse suspension, but had lower lattice energy. In the in vitro dissolution test, both microsuspension and nanosuspension showed increased dissolution rate. In the in vivo evaluation, compared to coarse suspension, RH nanosuspension exhibited significant increase in AUC(0-t), C(max) and decrease in T(max), MRT. Nevertheless, RH microsuspension did not display any significant differences in these pharmacokinetic parameters compared to the coarse suspension. The findings revealed that particle size reduction can influence RH absorption in gastrointestinal tract and nanosuspension can enhance oral bioavailability of RH in rats.     

Controlled release of paclitaxel from microemulsion containing PLGA and evaluation of anti-tumor activity in vitro and in vivo

The main objective of this study was to develop an optimal paclitaxel microemulsion prepared by self-microemulsifying drug delivery system (SMEDDS) which is a mixture of paclitaxel, tetraglycol, Cremophor ELP, and Labrafil 1944 and a paclitaxel microemulsion containing poly(D,L-lactide-co-glycolide) (PLGA) in order to offer controlled release of paclitaxel. To achieve this goal, paclitaxel and PLGA were dissolved by solubilizer like tetraglycol. There was not observed any change in molecular weight of PLGA after being solubilized by tetraglycol. The droplet size for all of the formulation of microemulsion was found in the range of 45-270nm by dynamic light scattering (DLS). It was observed that the droplet size of microemulsion without PLGA was smaller than that of microemulsion containing PLGA by transmission electron microscopy (TEM). The droplet of microemulsion containing PLGA was almost of spherical shape with smooth surface and there was no aggregation or adhesion among droplet of microemulsion by atomic force microscopy (AFM). The release behaviour of paclitaxel from microemulsion containing PLGA having various molecular weights (8K, 33K, and 90K) exhibited a biphasic pattern characterized by a fast initial release during the first 48h, followed by a slower and continuous release for 144h, in contrast that the release of paclitaxel from microemulsion without PLGA was finished during 24h. This result was identical with the result of anti-tumor activity in vitro of paclitaxel from microemulsion containing PLGA against human breast cancer cell line MCF7 and this formulation enhanced anti-tumor activity in vivo compared with microemulsion without PLGA against SKOV-3 human ovarian cancer cells bearing nude mice model.     

Rapid-onset sildenafil nasal spray carried by microemulsion systems: in vitro evaluation and in vivo pharmacokinetic studies in rabbits

An oleic acid-based microemulsion system with a member of the Tween series or Cremophor EL as the surfactant and a short-chain alcohol as the cosolvent was developed for rapid-onset intranasal delivery of sildenafil. The phase behaviour and solubilization capacity of the microemulsion system were characterized, and nasal absorption of sildenafil from the microemulsion formulations was investigated in rabbits. Sildenafil displayed a high solubility of 124?mg/mL in the microemulsion consisting of 40% oleic acid, 10% H(2)O, and 50% Tween 80:ethanol (EA) (at a 1:4 weight ratio). Nasal absorption of sildenafil from this microemulsion was found to be fairly rapid. With a 10-mg dose, the onset of action was arrived instantly following intranasal administration and the duration was over 3?h using an in vivo rabbit studies. In addition, nasal ciliotoxicity studies were carried out using in vivo rat nasal mucosa model and showed no ciliotoxicity. Therefore, the prepared systems are no serious nasal ciliotoxicity for intranasal administration. The microemulsion system composed of oleic acid, Tween 80, EA, and water may be a practical approach for the rapid-onset delivery of sildenafil for the treatment of erectile dysfunction.     

Formulation,characterization, in vitro and in vivo evaluation of castor oil based self-nano emulsifying levosulpiride delivery systems

Context: Levosulpiride (LSP) is a hydrophobic benzamide derivative used in the treatment of schizophrenia. SNEDDS were extensively practiced for systemic delivery of poorly aqueous soluble drugs to achieve maximum bioavailability.

Objective: The present study was focussed on the formulation, optimisation and evaluation of LSP SNEDDS using castor oil, for enhancement of drug absorption and bioavailability.

Materials and methods: Pseudo-ternary phase diagram was plotted to identify the range of SNEDDS components. Twenty formulations were designed, prepared and characterised by its particle size, zeta potential, viscosity, and stability. In vitro dissolution data modelling was performed. Microscopy, FTIR and in vivo bioavailability studies were conducted for optimum formulation.

Results, discussion and conclusion: F18 containing castor oil, 0.9?mL; PEG 600, 1.36?mL and Tween 80, 2.74?mL was found to be optimum. The optimised formulation had shown uniform globule size, no interactions of LSP with SNEDDS components and higher pharmacokinetic parameters than that of commercial preparation.     

Preparation and in vitro/in vivo evaluation of sustained-release venlafaxine hydrochloride pellets

The objective of this study was to prepare different venlafaxine hydrochloride sustained-release products and to elucidate the influence of composition of the coating film on the in vitro drug release profiles and in vivo pharmacokinetics. Pellets were prepared by a standardized process of extrusion/spheronization. A selected fraction size (0.8-1.0 mm diameter) of pellets of each formulation was coated with Eudragit NE30D or ethylcellulose (10 cps). Many efforts have been made to tailor drug release rate by choosing different coating materials, different percent of pore forming components and coating weight variation to achieve a desired sustained-release effect. The dissolution studies were performed and data were analyzed in terms of cumulative release as a function of time. The influence on the release of venlafaxine from sustained-release capsules was observed in dissolution media of different pH and gradient pH. Scanning electron microscope (SEM) micrographs revealed morphological changes of the pellet coating surface which were related to in vitro drug release profiles. The relative bioavailability for Formulation 1 and Formulation 2 was evaluated in six healthy beagle dogs after oral administration in a fast state using sustained-release capsules (Effexor XR) as a reference. The results suggested that Formulation 1 and Formulation 2 both had better bioavailability compared with Effexor XR. It could be found that there existed quite difference in the in vivo release and oral absorption performances, despite the similar in vitro drug release behavior for the two formulations. It might be attributable to complex in vivo environment and then variation in the release behavior. Thus differences in the film micro-structure and surface roughness caused by aqueous dispersion and organic solvent coating techniques strongly influence the in vivo release and oral absorption performances.     

Pulsatile systems for colon targeting of budesonide: In vitro and in vivo evaluation

The purpose of this study is to increase the lag time and prevent release of budesonide, a corticosteroid drug used in Crohn’s disease for the first 5?h and efficiently deliver it to the colon. Eudragit S100 spray-coated capsules and pulsatile systems using tablet plugs of cellulose acetate butyrate (CAB), HPMC K4M, guar gum, and pectin were prepared. Eudragit S100-coated capsules released 80.62% after 5?h. In pulsatile systems, decreasing the ratio of the polymer significantly increased the rate and extent of drug release. Spray-coating with EUD S100 decreased the extent of drug release to 48.41%, 69.94%, 80.58%, and 45.23% in CAB, HPMC K4M, pectin, and guar gum, respectively; however, the entire amount was released in the target area. In the presence of bacterial enzymes, selected formulas showed nearly 100% release. X-ray imaging performed to monitor the capsules throughout the GIT in human volunteers of the capsules and spray-coated pulsatile systems with 25% guar gum in the plug showed bursting in the transverse and ascending colon, respectively. Both formulations showed marked reduction in induced rabbit colitis model.     

Biocompatible lidocaine and prilocaine loaded-nanoemulsion system for enhanced percutaneous absorption: QbD-based optimisation,dermatokinetics and in vivo evaluation

Abstract

Barrier properties of the skin and physicochemical properties of the drugs are the main hiccups in delivering local anaesthetic molecules topically. The present work endeavours for systematic optimisation and evaluation of nanoemulsions (NEs) of local anaesthetic drugs, lidocaine and prilocaine, employing the systematic approach of Quality by Design. A 3³ Box–Behnken design was employed for systematic optimisation of the factors obtained from screening studies employing Plackett–Burman design and risk assessment studies. The superior permeation rates, and higher concentrations of the drugs in skin layers from the optimised NE carriers, were achieved in permeation and dermatokinetic studies, when compared to marketed cream. Furthermore, rapid onset of action was demonstrated by the NE system in rabbit eye corneal reflex model and biocompatibility was confirmed from the absence of any marked skin change(s) in the normal skin histology. The developed NE systems demonstrated it as a promising carrier for topical delivery of lidocaine and prilocaine.     

水飞蓟素自微乳化浓乳的制备和体内外评价

目的:制备和评价水飞蓟素自微乳化浓乳(self-microemulsifying concentrated microemulsion,SCM)。方法:由以前的工作确定微乳的组成;以光散射法测定微乳的粒度及其分布;用透射电镜考察微乳的形态;用加速试验的方法考察SCM的物理和化学稳定性;用透析袋法评价该SCM的释放特征;以市售水飞蓟素胶囊为对照,测定了SCM经家犬口服的生物利用度。结果:SCM在5 min内即可形成粒径均匀、单分散的微乳,其平均粒径为21 nm;所形成微乳乳滴为球形;SCM于加速试验条件下放置6个月,所有指标未见明显变化;SCM和市售水飞蓟素胶囊在12 h的释放百分率分别为(72.5±4.0)%及(44.0±6.9)%;SCM和水飞蓟素胶囊的AUC值分别为(4.78±1.02)和(2.09±0.15)μg.mL-1.h,相对生物利用度为227.2%。结论:本实验研制的SCM可迅速自发形成粒径均匀、液滴呈球形的微乳,且长期放置的稳定性良好,体外释放特征和家犬体内生物利用度均优于市售水飞蓟素胶囊,有望成为水飞蓟素的优良口服制剂。     

Preparation and in vitro/in vivo evaluation of sustained-release metformin hydrochloride pellets.

In this study, metformin hydrochloride (MH) sustained-release pellets were successfully prepared by centrifugal granulation. Seed cores preparation, drug layering, talc modification and coating of polymeric suspensions were carried out in a centrifugal granulator. Talc modification was performed before coating in order to overcome the high water solubility of metformin. The influence of surface modification by talc, the effects of Eudragit types and ratios, as well as the correlation between in vitro release and in vivo absorption were investigated in detail. Experimental results indicated that talc modification made a decisive contribution to controlling the drug release by avoiding drug dumping. Three dissolution media: 0.1 M HCl, distilled water and pH 6.8 phosphate buffer were employed to determine the in vitro release behaviors of the above metformin hydrochloride pellets. The relative bioavailability of the sustained-release pellets was studied in 12 healthy volunteers after oral administration in a fast state using a commercially available immediate release tablet (Glucophage) as a reference. Following coating with a blend of Eudragit L30D-55 and Eudragit NE30D (1:20), at 7% or 10% coating level, respectively (referred to as F-2, F-3), the pellets acquired perfect sustained-release properties and good relative bioavailability. The Cmax, Tmax and relative bioavailability for F-2 and F-3 coated pellets were 1.21 microg/ml, 6 h, 97.6% and 1.65 microg/ml, 8 h, 165%, respectively. Combined use of two Eudragit polymers with different features as coating materials produced the desired results. Restricted delivery of metformin hydrochloride to the small intestine from differently coated pellets resulted in increased relative bioavailability and a sustained release effect. The adoption of several different pH dissolution media established a better relationship between the in vitro release and in vivo absorption of the sustained-release pellets.     

Curcumin entrapped hyaluronan containing niosomes: preparation,characterisation and in vitro/in vivo evaluation

Curcumin, a natural polyphenolic compound, has numerous pharmacological activities; while it faces several bioavailability problems, due to its poor solubility and stability. So, many nanostructures have been designed to overcome these drawbacks. The aim of this study was to prepare a polymeric niosomal structure by incorporating hyaluronan to improve curcumin efficiencies. Hyaluronan containing niosomes were prepared by thin film hydration medium with slight modifications. In the formulation of hyaluronan containing niosomes size and zeta potential studies, Atomic Force Microscopy (AFM), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), X-Ray Diffraction (XRD), in-vitro release test, DPPH antioxidant assay and in-vivo anti-inflammatory test were investigated. The results showed that hyaluronan containing niosomes were 249.83?±?6.38?nm and the entrapment of curcumin was 98.28?±?0.278% (w/w). In addition, the shape of the hyaluronan containing niosomes was spherical. 500?µl of the prepared formulation with 4.002?×?10^?7 moles of curcumin showed 100% antioxidant effect. Moreover, the anti-inflammatory effect of the hyaluronan containing niosomes was higher than the anti-inflammatory effect of the simple suspension of curcumin.     

Formulation,characterization, and in vitro/ex vivo evaluation of quercetin-loaded microemulsion for topical application

The aim of this study was to develop a new microemulsion formulation for topical application of poorly soluble drug named quercetin. In order to design suitable microemulsion system, the pseudo-ternary phase diagrams of microemulsion systems were constructed at different surfactant/co-surfactant ratios using tween 80 as surfactant, transcutol^® P as a co-surfactant and oleic acid as an oil phase. Some physicochemical properties such as droplet size, density, refractive index, electrical conductivity, pH, surface tension, and viscosity of the microemulsion systems were measured at 298.15 K. The average hydrodynamic droplet size of the optimized microemulsions was obtained by dynamic light scattering method. Morphology assessment of the optimized quercetin-loaded microemulsion by transmission electron microscopy analysis indicated that the particles have the size of about 25?nm and spherical with narrow size distribution. Equilibrium solubility, in vitro drug release at a 24?h time period, release kinetic evaluation as well as ex vivo permeation and retention of quercetin-loaded microemulsions through rat skin has been investigated. The obtained results showed a slow release behavior without any transdermal delivery. Most of the formulations fitted best with zero-order kinetic model with a non-Fickian mechanisms. This study illustrated that the proposed QU-microemulsion has a good potential for use in sunscreen formulations.

     

Cow ghee fortified ocular topical microemulsion; in vitro,ex vivo,and in vivo evaluation

Abstract

Aim: Utility of cow ghee (CG) as permeation enhancer in development of topical ocular microemulsion (ME) for delivery of fluocinolone acetonide (FA) to posterior eye.

Methods: For ME preparation, oil, surfactant and cosurfactant were screened based on solubility of FA. Pseudoternary phase diagrams were constructed to determine their ratios. The developed MEs were characterised for their physicochemical properties like size, polydispersity index, zeta potential, and stability etc. They were evaluated for ex vivo permeation and irritation. In vivo pharmacokinetic studies were performed on Sprague dawley rats.

Results: Lauroglycol as oil, labrasol as surfactant and Transcutol as cosurfactant were selected. The optimised ratio of oil:surfactant:cosurfactant:water was 4:23:23:50. The developed FA loaded ME fortified with CG was characterised. Ex vivo study revealed higher permeation and non-irritancy. In vivo pharmacokinetic study showed retention of CG fortified ME in posterior rat eye.

Conclusion: Present investigation established CG as permeation enhancer for ocular topical formulation.     

Formulation and optimization of duloxetine hydrochloride buccal films: in vitro and in vivo evaluation

Duloxetine hydrochloride (DH) is a serotonin–norepinephrine reuptake inhibitor (SSNRI) indicated for the treatment of depression. Duloxetine suffers from reduced oral bioavailability (≈50%) due to hepatic metabolism. This study aims to develop DH buccoadhesive films to improve its bioavailability. DH buccoadhesive films were prepared adopting the solvent casting method using hydroxypropyl methylcellulose (HPMC) and polyvinyl alcohol (PVA). The prepared films were evaluated for weight uniformity, drug content, surface pH, swelling index, mucoadhesion strength and drug release percentages. Accelerated stability and bioavailability studies in healthy human volunteers were also performed for the selected films. Results of the evaluation tests showed that the optimum physicochemical characters were obtained by the films prepared with 2% HPMC using 10% propylene glycol (F2 films). Accelerated stability studies revealed that DH showed proved stability throughout the experiment time. DH bioavailability from F2 films was determined and compared with that of the marketed oral capsules (Cymbalta^® 30?mg). The pharmacokinetic results showed that C_max for F2 was higher than the market product. In addition, ANOVA analysis showed that a T_max of F2 film was significantly lower, while, the AUC_0–72 of F2 was significantly higher than that of Cymbalta capsules. The percentage relative bioavailability of DH from F2 was found to be 296.39%. Therefore, the prepared buccal films offer an alternative route for the administration of DH with the possibility of improving its bioavailability.     

Preparation and in vitro/in vivo evaluation of metformin hydrochloride rectal dosage forms for treatment of patients with type II diabetes

Background: Metformin hydrochloride (MtHCL) is an oral antidiabetic drug and has many other therapeutic benefits. It has poor bioavailability, narrow absorption window and extensive liver metabolism. Moreover, children and elders face difficulty to swallow the commercial oral tablets.

Objectives: Preparation, in vitro/in vivo evaluation of MtHCL suppositories for rectal administration to solve some of these problems.

Methods: Suppository fatty bases (Witepsol^®, Suppocire^® and Massa^®; different grades) and PEG bases 1000, 4000 and 6000 (different ratios), were used to prepare rectal suppository formulations each containing 500?mg drug. These were characterized for manufacturing defects, and pharmacotechnical performance and formulations showing superior results were subjected to bioavailability testing in human volunteers compared with the commercial oral tablet (Ref) applying LC–MS/MS developed analytical technique.

Results: The preparation method produced suppositories with satisfactory characteristics and free of manufacturing defects. The fatty bases were superior compared with PEG bases regarding the physical characteristics. Three formulations were chosen for bioavailability testing and the results showed comparable bioavailability compared to the Ref.

Conclusions: The fatty bases showed superior characteristics compared with the PEG bases. MtHCL formulated in selected fatty bases could be a potential alternative to the commercial oral tablets particularly for pediatric and geriatric patients.     

Pilocarpine hydrochloride liposomes: characterization in vitro and preliminary evaluation in vivo in rabbit eye

Liposomes containing either pilocarpine hydrochloride or pilocarpine free base were prepared by the sonication method. This manufacturing process yielded after removal of non-encapsulated solute, small multilamellar vesicles (MLV) as was confirmed by electron microscopy examinations. For an identical liposomal composition, the encapsulation capacity and the drug content of the liposomes were drastically higher for pilocarpine hydrochloride than for pilocarpine free base. Investigation of the preparative parameters revealed that increasing the initial amount of drug decreased the drug content and the encapsulation efficiency of the liposomes formed. Since fixed amounts of lipids were used, the volume sequestration rate decrease was attributed to a moderate viscosity increase of the dispersion medium. Increase of phospholipid concentration at a constant ratio of cholesterol and dicetylphosphate to phosphatidylcholine reduced the aqueous volume entrapped per mg of lipid and subsequently the pilocarpine content in the liposomes. Negatively charged liposomes gave larger rates of pilocarpine hydrochloride and aqueous volume encapsulation than neutral liposomes but, on the contrary, positively charged liposomes gave the lowest rates of pilocarpine hydrochloride and aqueous volume encapsulation. Thus, for drug carrying the same net charge as the phospholipids an increase in the surface charge density of the liposome was not only ineffective, but actually resulted in a lower drug encapsulation due to electrostatic repulsion. Preliminary in vivo results on rabbit eyes suggested that the liposomal vehicle was probably unable to improve sufficiently the corneal penetration of pilocarpine to reach satisfactory therapeutic levels when administered at lower concentrations than commonly used.