Brain targeting of chitosan-based diazepam mucoadhesive microemulsions via nasal route: formulation optimization,characterization, pharmacokinetic and pharmacodynamic evaluation

Objective: The aim of present investigation was to develop microemulsions (MEs) and mucoadhesive microemulsions (MME) of diazepam for brain uptake through nasal administration for the treatment of seizure emergency.

Significance: Status epilepticus (SE) is a medical emergency, requires intravenous administration of diazepam which requires hospitalization of patient. Initiation of therapy at home via nasal administration of diazepam could prevent the damage of brain due to delay of therapy initiation.

Methods: Diazepam MEs were prepared by phase titration method, optimized by using Box–Behnken design. The influence of independent variables oleic acid, surfactant mixture (tween 80:propylene glycol), and water on dependent variables size, flux, and zeta potential was investigated. Optimized MEs, MMEs, and Calmpose (i.v route) were evaluated for pharmacokinetic and pharmacodynamic studies on rats.

Results: MME2 composed of oleic acid (5), surfactant mixture (50), water (45), and chitosan (0.5) showed size of 96.45?nm, PDI 0.21 and zeta potential 13.52?mV. MME2 showed significantly high flux of 846.96?±?34?µg/cm2/h and AUCbrain 1206.49?±?145.8. The drug targeting efficiency (314%) and direct nose-to-brain transport (68.1%) of MME2 were significantly high compared to Calmpose (i.v) and ME. The latency periods of minimal clonal seizures and generalized tonic–clonic seizures of MME2 was significantly increased (p?<?0.0001) compared to drug solution and Calmpose (i.v).

Conclusion: The brain uptake of diazepam from chitosan-based MMEs via nasal route is significantly high compared to i.v route.     

Solid lipid nanoparticles as vesicles for oral delivery of olmesartan medoxomil: formulation,optimization and in vivo evaluation

Objective: Olmesartan medoxomil (OLM) is an antihypertensive drug with low oral bioavailability (28%) resulting from poor aqueous solubility, presystemic metabolism and P-glycoprotein mediated efflux. The present investigation studies the role of lipid nanocarriers in enhancing the OLM bioavailability through oral delivery.

Materials and methods: Solid lipid nanoparticles (SLN) were prepared by solvent emulsion-evaporation method. Statistical tools like regression analysis and Pareto charts were used to detect the important factors effecting the formulations. Formulation and process parameters were then optimized using mean effect plot and contour plots. The formulations were characterized for particle size, size distribution, surface charge, percentage of drug entrapped in nanoparticles, drug–excipients interactions, powder X-ray diffraction analysis and drug release in vitro.

Results and discussion: The optimized formulation comprised glyceryl monostearate, soya phosphatidylcholine and Tween 80 as lipid, co-emulsifier and surfactant, respectively, with an average particle size of 100?nm, PDI 0.291, zeta potential of ?23.4?mV and 78% entrapment efficiency. Pharmacokinetic evaluation in male Sprague Dawley rats revealed 2.32-fold enhancement in relative bioavailability of drug from SLN when compared to that of OLM plain drug on oral administration.

Conclusion: In conclusion, SLN show promising approaches as a vehicle for oral delivery of drugs like OLM.     

Formulation,optimization, hemocompatibility and pharmacokinetic evaluation of PLGA nanoparticles containing paclitaxel

Objective: Paclitaxel (PTX)-loaded polymer (Poly(lactic-co-glycolic acid), PLGA)-based nanoformulation was developed with the objective of formulating cremophor EL-free nanoformulation intended for intravenous use.

Significance: The polymeric PTX nanoparticles free from the cremophor EL will help in eliminating the shortcomings of the existing delivery system as cremophor EL causes serious allergic reactions to the subjects after intravenous use.

Methods and results: Paclitaxel-loaded nanoparticles were formulated by nanoprecipitation method. The diminutive nanoparticles (143.2?nm) with uniform size throughout (polydispersity index, 0.115) and high entrapment efficiency (95.34%) were obtained by employing the Box–Behnken design for the optimization of the formulation with the aid of desirability approach-based numerical optimization technique. Optimized levels for each factor viz. polymer concentration (X1), amount of organic solvent (X2), and surfactant concentration (X3) were 0.23%, 5?ml %, and 1.13%, respectively. The results of the hemocompatibility studies confirmed the safety of PLGA-based nanoparticles for intravenous administration. Pharmacokinetic evaluations confirmed the longer retention of PTX in systemic circulation.

Conclusion: In a nutshell, the developed polymeric nanoparticle formulation of PTX precludes the inadequacy of existing PTX formulation and can be considered as superior alternative carrier system of the same.     

Spray drying of a poorly water-soluble drug nanosuspension for tablet preparation: formulation and process optimization with bioavailability evaluation

Spray drying experiments of an itraconazole nanosuspension were conducted to generate a dry nanocrystal powder which was subsequently formulated into a tablet formulation for direct compression. The nanosuspension was prepared by high pressure homogenization and characterized for particle-size distribution and surface morphology. A central composite statistical design approach was applied to identify the optimal drug-to-excipient ratio and spray drying temperature. It was demonstrated that the spray drying of a nanosuspension with a mannitol-to-drug mass ratio of 4.5 and at an inlet temperature of 120?°C resulted in a dry powder with the smallest increase in particle size as compared with that of the nanosuspension. X-ray diffraction results indicated that the crystalline structure of the drug was not altered during the spray-drying process. The tablet formulation was identified by determining the micromeritic properties such as flowability and compressibility of the powder mixtures composed of the spray dried nanocrystal powder and other commonly used direct compression excipients. The dissolution rate of the nanocrystal tablets was significantly enhanced and was found to be comparable to that of the marketed Sporanox®. No statistically significant difference in oral absorption between the nanocrystal tablets and Sporanox® capsules was found. In conclusion, the nanosuspension approach is feasible to improve the oral absorption of a BCS Class II drug in a tablet formulation and capable of achieving oral bioavailability equivalent to other well established oral absorption enhancement method.     

A combination of complexation and self-nanoemulsifying drug delivery system for enhancing oral bioavailability and anticancer efficacy of curcumin

Abstract

Objective: Curcumin, the golden spice from Indian saffron, has shown chemoprotective action against many types of cancer including breast cancer. However, poor oral bioavailability is the major hurdle in its clinical application. In the recent years, self-nanoemulsifying drug delivery system (SNEDDS) has emerged as a promising tool to improve the oral absorption and enhancing the bioavailability of poorly water-soluble drugs. In this context, complexation with lipid carriers like phospholipid has also shown the tremendous potential to improve the solubility and therapeutic efficacy of certain drugs with poor oral bioavailability.

Methods: In the present investigation, a systematic combination of both the approaches is utilized to prepare the phospholipid complex of curcumin and facilitate its incorporation into SNEDDS. The combined use of both the approaches has been explored for the first time to enhance the oral bioavailability and in turn increase the anticancer activity of curcumin.

Results: As evident from the pharmacokinetic studies and in situ single pass intestinal perfusion studies in Sprague–Dawley rats, the optimized SNEDDS of curcumin–phospholipid complex has shown enhanced oral absorption and bioavailability of curcumin. The cytotoxicity study in metastatic breast carcinoma cell line has shown the enhancement of cytotoxic action by 38.7%. The primary tumor growth reduction by 58.9% as compared with the control group in 4T1 tumor-bearing BALB/c mice further supported the theory of enhancement of anticancer activity of curcumin in SNEDDS.

Conclusion: The developed formulation can be a potential and safe carrier for the oral delivery of curcumin.     

Chitosan based mucoadhesive nanoparticles of ketoconazole for bioavailability enhancement: formulation,optimization, in vitro and ex vivo evaluation

Purpose: The conventional dosage form of Ketoconazole (KZ) shows poor absorption due to rapid gastric emptying. Chitosan based mucoadhesive nanoparticles (NPs) of KZ were developed to efficiently release drug at its absorption window i.e. stomach and the site of action i.e. esophagus.

Method: The NPs were prepared by ionic gelation method. Concentration of polymer, cross-linking agent and ratio of drug/polymer as well as polymer/cross linking agent were optimized.

Results: NPs had 69.16?±?5.91% mucin binding efficiency, particle size of 382.6?±?2.384?nm, ζ potential of +48.1?mv and entrapment efficiency of 59.84 ± 1.088%. DSC thermogram indicated absence of any drug polymer interaction. The drug release was by controlled, non-fickian diffusion mechanism. Ex vivo diffusion studies were performed by emptying the stomach contents after 2?h to simulate in vivo gastric emptying. The results showed that drug diffusion from the solution across stomach mucosa stopped after emptying whereas that from the NPs continued upto 5?h. Hence we could conclude that the NPs must have adhered to the stomach mucosa and thereby would have been retained at this absorption site even after gastric emptying.

Conclusion: The orally delivered KZ loaded mucoadhesive NPs can be used as an efficient carrier for delivering drug at its absorption window i.e. the stomach and the site of action i.e. esophagus even after gastric emptying.     

Preparation and optimization of a novel microbead formulation to improve solubility and stability of curcumin

Curcumin is an active ingredient which is poorly water-soluble, leading to a low oral bioavailability. The aim of this research was to prepare a novel microbead formulation, and to solubilize, solidify, and improve storage stability of curcumin. Firstly, curcumin was solubilized with Kolliphor^TM RH40 and then microencapsulated by cross linking of sodium alginate with calcium chloride. A three-factor, three-level Box–Behnken design was employed to acquire the optimum microbead formulation, namely the best entrapment efficiency and in vitro curcumin release. The independent variables were sodium alginate concentration, calcium chloride concentration, and the weight of curcumin solution, while the dependent variables were entrapment efficiency and in vitro curcumin release. The optimized microbead formulation was 2.06% sodium alginate, 24.33% calcium chloride, and 1.28 g curcumin solution (containing curcumin and RH40 with a ratio of 1:22, g/g). Results showed that high concentrations of sodium alginate and calcium chloride could increase the entrapment efficiency. In vitro curcumin release decreased with increasing of sodium alginate as well as decreasing of calcium chloride. In conclusion, the optimum microbead formulation increased the solubility of curcumin and enhanced its stability, and achieved a high entrapment efficiency and in vitro curcumin release.     

Improved oral bioavailability of fexofenadine hydrochloride using lipid surfactants: ex vivo,in situ and in vivo studies

The aim of the present study was to improve the dissolution, permeability and therefore oral bioavailability of the fexofenadine hydrochloride (FEX), by preparing lipid surfactant based dispersions using self-emulsifying carriers, i.e. Gelucire 44/14 (GLC) and d-α-tocopheryl polyethylene glycol 1000 succinate (Vitamin E TPGS or TPGS). The reprecipitation studies were conducted using these carriers to evaluate inhibition of reprecipitation by maintaining super saturation state. The aqueous solubility of the FEX was increased linearly with increasing GLC, TPGS concentrations as verified by the phase solubility studies. The dispersions of FEX were prepared in different drug/GLC (GD) and drug/TPGS (TD) ratios by melt method and evaluated. The prepared dispersions showed improved dissolution rate in distilled water as dissolution media and highest dissolution rate was achieved with dispersions prepared using TPGS. The solid state characterization was carried by differential scanning calorimetry and scanning electron microscopy indicated reduced crystallinity of the drug. Fourier transform infrared spectroscopy revealed the compatibility of drug with carriers. The ex vivo permeation studies conducted using intestinal gut sac technique, resulted in reduced efflux of the drug by inhibiting intestinal P-glycoprotein from the dispersions. The in situ perfusion studies and in vivo pharmacokinetic studies in male wistar rats showed improved absorption and oral bioavailability from the prepared dispersions as compared to pure drug.     

Implementation of two different experimental designs for screening and optimization of process parameters for metformin-loaded carboxymethyl chitosan formulation

Abstract

Metformin (MET) was effectively encapsulated into O-carboxymethyl chitosan (O-CMC) polymeric formulation using an experimental design method. Six factors Plackett–Burman (PB) design was utilized to find the significant process parameters. Linear equations used to study the effect of each process parameters on particle size (PS), encapsulation efficiency (EE), and zeta potential (ZP) and the most influential three factors decided for further optimization. Optimization was carried out by implementing three-factor three-level Box–Behnken (BB) design. Mathematical models were generated by regression analysis for responses of PS, EE, and ZP. Two-step experimental design took into account for the preparation of optimized formulation with maximum %EE (72.78?±?9.7%) and minimum PS (225.67?±?5.53?nm) at optimum process conditions with a ZP of –5.22?mV for the nano-polymeric formulation in an economical matter by reduction chemical use and formulation time. Furthermore, the biological activity of the final formulation was determined by in vitro cytotoxicity study compared to free MET. The cytotoxicity result reveals that both pure drug and nano-formulation biocompatible with MCF10A non-tumorigenic cell line and lethal for the MCF7 cell line. These in vitro results were the first helpful step to further investigate O-CMC loaded MET nanoparticles in diagnostic and therapeutic applications of breast cancer.     

Development of isradipine loaded self-nano emulsifying powders for improved oral delivery: in vitro and in vivo evaluation

Isradipine (ISR) is a potent calcium channel blocker with low oral bioavailability due to low aqueous solubility, extensive first-pass metabolism and P-glycoprotein (P-gp)-mediated efflux transport. In the present investigation, an attempt was made to develop isradipine-loaded self-nano emulsifying powders (SNEP) for improved oral delivery. The liquid self-nano emulsifying formulations (L-SNEF/SNEF) of isradipine were developed using vehicles with highest drug solubility, i.e. Labrafil® M 2125 CS as oil phase, Capmul® MCM L8 and Cremophor® EL as surfactant/co-surfactant mixture. The developed formulations revealed desirable characteristics of self-emulsifying system such as nano-size globules ranging from 32.7 to 40.2?nm, rapid emulsification (around 60?s), thermodynamic stability and robustness to dilution. The optimized stable self-nano emulsifying formulation (SNEF₂) was transformed into SNEP using Neusilin US2 (SNEP_N) as adsorbent inert carrier, which exhibited similar characteristics of liquid SNEF. The solid state characterization of SNEP_N by Fourier transform infrared spectroscopy, differential scanning calorimetry, powder X-ray diffraction and scanning electron microscopic studies shown transformation of crystalline drug into amorphous form or molecular state without any chemical interaction. The in vitro dissolution of SNEP_N compared to pure drug was indicated by 18-fold increased drug release within 5?min. In vivo pharmacokinetic studies in Wistar rats showed significant improvement of oral bioavailability of isradipine from SNEP_N with 3- and 2.5-fold increments in peak drug concentration (C_max), area under curve (AUC_0–∞) compared to pure isradipine. In conclusion, these results signify the improved oral delivery of isradipine from developed SNEP.     

Nanostructured lipid carriers engineered for intranasal delivery of teriflunomide in multiple sclerosis: optimization and in vivo studies

Background: Multiple sclerosis (MS) is one of the most severe autoimmune disorder of the central nervous system (CNS).

Objective: The present research work was aimed to formulate and investigate teriflunomide (TFM)-loaded intranasal (i.n.) nanostructured lipid carriers (NLC) for the treatment of multiple sclerosis (MS).

Methods: The TFM-loaded NLC (TFM-NLC) nanoparticles were prepared by melt emulsification ultrasonication method using biodegradable and biocompatible polymers. The Box–Behnken statistical design was applied to optimize the formulation. The optimized NLC formulation was subjected to evaluate for particle size, entrapment efficiency (%), in vitro and ex vivo permeation. The safety and efficacy of optimized formulations were demonstrated using pharmacodynamic, subacute toxicity and hepatotoxicity data.

Results: Experimental data demonstrated that optimized NLC formulation (F17) showed significant size (99.82?±?1.36?nm), zeta potential (?22.29?±?1.8?mV) and % entrapment efficiency (83.39?±?1.24%). Alternatively, ex vivo permeation of TFM mucoadhesive NLC (TFM-MNLC) and TFM-NLC was observed 830?±?7.6 and 651?±?9.8?µg/cm², respectively. Whereas, TFM-MNLC shows around 2.0-folds more J_ss than the TFM-NLC. Finally, TFM-MNLC (i.n.) formulation produced the rapid remyelination in cuprizone-treated animals and decreases the number of entries in open compartment of EPM when compared with negative control and TFM-NLC (oral) animals. Simultaneously, the nanoformulation did not reflect any gross changes in hepatic biomarkers and subacute toxicity when compared with control.

Conclusions: Hence it can be inferred that the nose-to-brain delivery of TFM-MNLC can be considered as effective and safe delivery for brain disorders.     

Development of meloxicam in situ implant formulation by quality by design principle

Objective: The focus of this study was to develop and optimize in situ implant formulation of meloxicam by quality by design (QbD) principle for long-term management of musculoskeletal inflammatory disorders.

Methods: The formulation was optimized by Box–Behnken design with polylactide-co-glycolide (PLGA) level (X₁), N-methyl pyrrolidone level (X₂) and PLGA intrinsic viscosity (X₃) as the independent variables and initial burst release of drug (Y₁), cumulative release (Y₂), and dissolution efficiency (Y₃) as the dependent variables. The formulation was physicochemically characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy and powder X-ray diffraction (PXRD). Pharmacokinetic studies of the optimized formulation were performed on Sprague--Dawley rats.

Results: Y₁ was significantly affected by X₂ and X₃. Y₂ was affected by X₁ and X₃ while Y₃ was affected by all three independent variables employed in the formulations. Responses for the optimized formulation were in close agreement with the values predicted by the model. SEM photomicrographs indicated uniform gel formulation. No chemical interaction between the components of formulation was observed by FT-IR and meloxicam was found to be present in the amorphous form in the gel matrix as revealed by PXRD. The maximum plasma concentration (C_max), time to achieve C_max and area under plasma concentration curve were significantly different from those of the solution formulation used as the control. Plasma concentration of meloxicam was maintained above its IC₅₀ concentration required for COX-2 inhibition for 23 days.

Conclusion: Meloxicam in situ implant may provide long-term management of inflammatory conditions with improved patient compliance and better therapeutic index.     

Development and optimization of locust bean gum and sodium alginate interpenetrating polymeric network of capecitabine

Objective: The objective of the study was to develop interpenetrating polymeric network (IPN) of capecitabine (CAP) using natural polymers locust bean gum (LBG) and sodium alginate (NaAlg).

Significance: The IPN microbeads were optimized by Box–Behnken Design (BBD) to provide anticipated particle size with good drug entrapment efficiency. The comparative dissolution profile of IPN microbeads of CAP with the marketed preparation proved an excellent sustained drug delivery vehicle.

Methods: Ionotropic gelation method utilizing metal ion calcium (Ca²⁺) as a cross-linker was used to prepare IPN microbeads. The optimization study was done by response surface methodology based Box–Behnken Design. The effect of the factors on the responses of optimized batch was exhibited through response surface and contour plots. The optimized batch was analyzed for particle size, % drug entrapment, pharmacokinetic study, in vitro drug release study and further characterized by FTIR, XRD, and SEM. To study the water uptake capacity and hydrodynamic activity of the polymers, swelling studies and viscosity measurement were performed, respectively.

Results: The particle size and % drug entrapment of the optimized batch was 494.37?±?1.4?µm and 81.39?±?2.9%, respectively, closer to the value predicted by Minitab 17 software. The in vitro drug release study showed sustained release of 92% for 12?h and followed anomalous drug release pattern. The derived pharmacokinetic parameters of optimized batch showed improved results than pure CAP.

Conclusion: Thus, the formed IPN microbeads of CAP proved to be an effective extended drug delivery vehicle for the water soluble antineoplastic drug.     

Design and optimization of thermosensitive nanoemulsion hydrogel for sustained-release of praziquantel

Objective: This work aimed to develop an alternative sustained-release thermosensitive praziquantel-loaded nanoemulsion (PZQ-NE) hydrogel for better schistosomiasis treatment.

Significance: PZQ-NE-dispersed chitosan/glycerol 2-phosphate disodium/HPMC (NE/CS/β-GP/HMPC) hydrogel was successfully prepared to improve bioavailability of PZQ.

Methods: Solubility tests and pseudo-ternary phase diagrams were applied to screen optimal oils, surfactants and co-surfactants of NE. The hydrogels were characterized for gelling time, surface exudates, rheological properties and in vitro drug release. Formulation optimization of NE/CS/β-GP/HMPC hydrogel was conducted by Box–Behnken experimental design combined with response surface methodology. In vitro cytotoxicity of hydrogel was studied by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide method. The sustained-release property of PZQ in NE and optimized hydrogel was evaluated by pharmacokinetic study in rabbits.

Results: The formulation of PZQ-NE consisted of mass ratio of 12.5% capryol 90 containing PZQ (160?mg/g), 40% cremophor RH 40/tween 20 and transcutol HP (S/CoS?=?2:1), 47.5% deionized water. PZQ releasing from NE/CS/β-GP/HMPC hydrogels was best fitted to Higuchi model and governed by diffusion. Rheological investigation evidenced the themosensitive gelation of different hydrogel systems and their gel-like character at 37?°C. The optimized hydrogel formulation consisted of HPMC solution (103.69?mg/g), 3.03% (w/v) chitosan and 14.1% (w/v) β-GP showed no cytotoxicity when the addition of NE was no more than 100?mg/g. Pharmacokinetic parameters indicated that NE/CS/β-GP/HMPC hydrogel can significantly slow down drug elimination, prolong mean residence time and improve bioavailability of PZQ.

Conclusions: NE/CS/β-GP/HMPC hydrogel possessed sustained-release property and could be an alternative antischistosomal drug delivery system with improved therapeutic effect.     

7-Ethyl-10-hydroxycamptothecin proliposomes with a novel preparation method: optimized formulation,characterization and in-vivo evaluation

Context:?The proliposomes were used to solve the stability of the ordinary liposomes. Objective: 7-ethyl-10-hydroxycamptothecin (SN-38) proliposomes for intravenous (i.v.) administration were prepared successfully by a new method.

Materials and methods:?SN-38 liposomes solution was reconstituting automatically from proliposomes on contact with the acetic acid buffer solution (0.2 M, pH 2.6). The formulation was optimized by the Box–Behnken design. The physicochemical characteristics of the SN-38 proliposomes were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The stability studies were also carried on. The FLU–HPLC system was served to study the concentration of SN-38 in the plasma of Sprague Dawley (SD) rats.

Results:?The optimized formulation was SN-38: 0.03 g; Soybean phospholipid (SP): 0.6 g; dextrose: 3.00 g. The entrapment efficiency of the optimized formulation was >85% and the mean particle size was about 231 nm. The stability studies showed that SN-38 proliposomes were stable in dark at 20–25°C for 6 months at least. The pharmacokinetic parameters of i.v. administration demonstrated that the half-life of SN-38 loaded in the liposomes was prolonged in vivo.

Discussion and conclusion:?The SN-38 proliposomes was prepared successful by the analysis of TEM, SEM, DSC and XRD, and SN-38 liposomes could be reconstituted on contact with the hydration medium. SN-38 liposomes circulated for a longer time in the blood circulating system than SN-38 solution, which contributed to maintaining the drug action.     

Process,optimization, and characterization of budesonide-loaded nanostructured lipid carriers for the treatment of inflammatory bowel disease

The major challenge involved in the treatment of inflammatory bowel disease is targeted delivery of the drug at the site of inflammation. As nanoparticles possess the ability to accumulate at the site of inflammation, present investigation aims at development of Budesonide-loaded nanostructured lipid carrier systems (BDS-NLCs) for the treatment of inflammatory bowel disease. BDS-NLCs were prepared by employing a high pressure homogenization technique. Various preliminary trials were performed for optimization of the NLCs in which different processes, as well as formulation parameters, were studied. The BDS-NLCs was optimized statistically by applying a 3-factor/3-level Box–Behnken design. Drug concentration, surfactant concentration, and emulsifier concentration were selected as independent variables, and % entrapment efficiency and particle size were selected as dependent variables. The best batch comprises of 10%, 7%, and 20% w/w concentration of drug, surfactant, and emulsifier, respectively, with % entrapment efficiency of 92.66?±?3.42% and particle size of 284.0?±?4.53?nm. Further, in order to achieve effective delivery of nanoparticulate system to colonic region, the developed BDS-NLCs were encapsulated in Eudragit^® S100-coated pellets. The drug release studies of pellets depict intactness of BDS-NLCs during palletization process, with f₂ value of 75.879. The in vitro evaluation of enteric-coated pellets revealed that a coating level of 15% weight gain is needed in order to impart lag time of 5?h (transit time to reach colon). The results of the study demonstrate that the developed BDS-NLCs could be used as a promising tool for the treatment of inflammatory bowel disease.     

In vitro and in vivo evaluation of cyclodextrin-based nanosponges for enhancing oral bioavailability of atorvastatin calcium

The aim of this study was to explore the feasibility of complexing the poorly water-soluble drug atorvastatin calcium (AC) with β-cyclodextrin (β-CD) based nanosponges (NS), which offer advantages of improving dissolution rate and eventually oral bioavailability. Blank NS were fabricated at first by reacting β-CD with the cross-linker carbonyldiimidazole at different molar ratios (1:2, 1:4, and 1:8), then NS of highest solubilization extent for AC were complexed with AC. AC loaded NS (AC-NS) were characterized for various physicochemical properties. Pharmacokinetic, pharmacodynamics and histological finding of AC-NS were performed in rats. The prepared AC-NS showed particles size ranged from 408.7?±?12.9 to 423?±?15.9?nm while zeta potential values varied from ?21.7?±?0.90 to ?22.7?±?0.85?mV. The loading capacity varied from 17.9?±?1.21 to 34.1?±?1.16%. DSC, FT–IR, and PXRD studies confirmed the complexation of AC with NS and amorphous state of the drug in the complex. AC-NS displayed a biphasic release pattern with increase in the dissolution rate of AC as compared to plain AC. Oral administration of AC-NS (1:4 w/w, drug: NS) to rats led to 2.13-folds increase in the bioavailability as compared to AC suspension. Pharmacodynamics studies in rats with fatty liver revealed significant reduction (p?in vivo performance of AC.     

Formulation,optimization, and characterization of rifampicin-loaded solid lipid nanoparticles for the treatment of tuberculosis

Abstract

Mycobacterium tuberculosis, being the causative infectious agent, is the leading cause of death worldwide amongst the infectious disease. The low bioavailability of rifampicin (RIF), one of the vital constituent of antitubercular therapy, instigates an urge to develop nanocarrier, which can prevent its degradation in the acidic pH of the stomach. Solid lipid nanoparticles (SLNs) have been proven to be promising versatile platform for oral delivery of lipophilic drugs. Therefore, the current investigation demonstrates development of RIF-loaded solid lipid nanoparticles (RIF-SLNs) using high-pressure homogenization technique by employing a three-level, three-factor Box–Behnken design. Concentration of drug, concentration of emulsifier, and homogenization pressure were selected as an independent variables, and %drug loading (%DL), %entrapment efficiency (%EE), and particle size were selected as dependent variables. The developed RIF-SLNs were characterized for particle size, polydispersity index, zeta potential, %EE, %DL, differential scanning calorimetry, X-ray diffraction, and TEM analysis. The mean diameter of RIF-SLNs was found to be 456?±?11?nm, %EE of 84.12?±?2.78%, and %DL of 15.68?±?1.52%. The in vitro lipolysis experiments revealed that RIF-SLNs stabilized using poloxamer 188, exhibited antilipolytic effect. Furthermore, the in vitro GI stability studies (at pH 1.2, pH 4.5, pH 6.8, and pH 7.4) revealed that the developed system could withstand various gastrointestinal tract media. The in vitro dissolution studies depicted biphasic drug release profile for drug-loaded SLNs revealing best fit with Weibull model. The accelerated stability studies for 6?months does not revealed any significant change in characteristics of developed RIF-SLNs.