Formulation and optimization of coated PLGA - Zidovudine nanoparticles using factorial design and in vitro in vivo evaluations to determine brain targeting efficiency

Drug Delivery Systems and Strategies to Overcome the Barriers of Brain

The transport of drugs to the central nervous system is the most challenging task for conventional drug delivery systems. Reduced permeability of drugs through the blood-brain barrier is a major hurdle in delivering drugs to the brain. Hence, various strategies for improving drug delivery through the blood-brain barrier are currently being explored. Novel drug delivery systems (NDDS) offer several advantages, including high chemical and biological stability, suitability for both hydrophobic and hydrophilic drugs, and can be administered through different routes. Furthermore, the conjugation of suitable ligands with these carriers tend to potentiate targeting to the endothelium of the brain and could facilitate the internalization of drugs through endocytosis. Further, the intranasal route has also shown potential, as a promising alternate route, for the delivery of drugs to the brain. This can deliver the drugs directly to the brain through the olfactory pathway. In recent years, several advancements have been made to target and overcome the barriers of the brain. This article deals with a detailed overview of the diverse strategies and delivery systems to overcome the barriers of the brain for effective delivery of drugs.

QbD-based Formulation Optimization and Characterization of Polymeric Nanoparticles of Cinacalcet Hydrochloride with Improved Biopharmaceutical Attributes

Objectives

The aim of the present work was to prepare QbD enabled optimization, and to improve the oral bioavailability of freeze-dried polymeric nanoparticles of cinacalcet hydrochloride manufactured by nanoprecipitation and ultrasonication methods using polymers PLGA, and poloxamer-188.

Materials and Methods

The initial screening and optimization were carried out for the formulations by employing Taguchi and Box-Behnken Designs. The FT-IR and DSC revealed no interactions and had no incompatibility among the selected drug and polymers. The nanoparticles were characterized for % drug release, particle size analysis, zeta potential, PDI, SEM, TEM, P-XRD, TGA, DTA, in vitro, and in vivo drug release study.

Results

In vitro drug release study showed sustained release of the drug from the optimized batch by diffusion mechanism. The optimized nanoparticle formulation was recognized by numerical and graphical methods using validation of the experimental model. The optimized batch was stable as per the ICH stability guidelines for 6 months with no considerable alternation noticed in particle size, entrapment efficiency, and in vitro drug release. The pharmacokinetic parameters of AUC and Cmax data for the optimized formulation increased 3- and 2.9-folds compared to the pure-drug suspension.

Conclusion

The prepared polymeric nanoparticles formulation is an alternative delivery system for enhanced therapeutic efficacy and bioavailability potential of a model drug to manage long-term normocalcemia in patients with preliminary hyperparathyroidism.

In Vitro Studies of Prednisolone Loaded PLGA Nanoparticles-Surface Functionalized With Folic Acid on Glioma and Macrophage Cell Lines

Background: Glucocorticoids are employed for their anti-inflammatory effects in treatingglioma, whose cells are known to overexpress the folate receptors. Some glucocorticoids haveshown inhibitory effects, but the efficacy of prednisolone when delivered via folate receptormediateduptake, has not been attempted. The study aimed to assess the efficacy of targeteddelivery of prednisolone on glioma cell lines like C6 and U87 via the folate receptors. Methods: Targeted delivery of prednisolone was achieved by initially conjugating folic acid (FA)to the di-block copolymer of polylactic acid (PLA) – polyethylene glycol (PEG). This moietycarrying di-block copolymer was incorporated on the surface of the drug-loaded poly lactic-coglycolicacid (PLGA) nanoparticle (NP) by employing the Interfacial Activity Assisted SurfaceFunctionalization (IAASF) technique. The NPs were evaluated for size, zeta potential, and drugloading. It was characterized using particle size analyser, SEM, 1H-NMR, and XRD. cell uptake,cytotoxicity, and anti-inflammatory activities were studied for various formulations. Results: The cytotoxicity assay indicated a high cell growth inhibitory effect of drug encapsulatedNPs with FA moiety as compared to free drug and NPs without the moiety for an incubationperiod of three, five, and six days. The growth-inhibitory effect of the free drug was short-lived,whereas FA functionalized NPs showed higher uptake and sustained inhibitory effect, and werealso able to significantly control the release of pro-inflammatory cytokines like tumour necrosisfactor-alpha (TNF-α) and nitric oxide (NO). Conclusion: Uptake, attenuation of pro-inflammatory signals, and the inhibitory effect ofprednisolone on the cells were more effective when targeted with the FA moiety on the surfaceof NPs as compared to free drug and NPs without the moiety.

Brain uptake and accumulation of new levofloxacin-doxycycline combination through the use of solid lipid nanoparticles: Formulation; Optimization and in-vivo evaluation

The objective of this study is to investigate the feasibility of delivery of novel levofloxacin/ doxycycline (LEVO/DOX) combination to the brain by intranasal route to achieve a significant local concentration in the brain and a direct nose-to-brain pathway. Solid lipid nanoparticles (SLN) were selected as a drug carrier and employed Box-Behnken design for optimizing LEVO/DOX-SLN to achieve minimum particle size and maximum apparent entrapment efficiency (EE). SLNs were prepared by hot emulsification and characterized. In vitro release of optimized formulations showed prolonged drug release from the optimized formulation. The results of pharmacokinetic study of the optimized SLN-HPMC gel in plasma and brain revealed significant increase in the brain peak concentration (420, 315 ng/g), the AUC _0-360 min (57130 and 48693.13 ng. min/g) in comparison to intranasal LEVO/DOX free solution with the values of (160, 120) ng/g, (36850, 27637.5 ng⋅min/g) for LEVO and DOX, respectively. The optimized LD-SLN-HPMC gel gave a drug-targeting efficiency (DTE %) of 149.815 and 161.969 for LEVO and DOX, respectively, in comparison to the intravenous route. Moreover, the optimized formulation had a direct transport percentage (DTP %) of 33.285 and 40.236 for LEVO and DOX, respectively, which indicates a significant contribution of direct nose-to-brain pathway in brain drug delivery.

Preparation of Atorvastatin Loaded Chitosan Nanoparticles: In Vitro and In Vivo Evaluations

This study is aimed at the preparation and evaluation of atorvastatin (AN)-loaded chitosan (CS) nanoparticles to achieve improved bioavailability of atorvastatin as its bioavailability is very poor. Chitosan is a popular choice in the application as a drug delivery carrier due to its biocompatibility, chemical versatility, aqueous solubility and low cost. Hence, a total of nine formulations (AN1–AN9) were prepared to study the effects of CS:tripolyphosphate (TPP) ratio and the amount of drug. The best formulation was selected by calculating the overall desirability (OD) factor. Among all, AN9 was found to possess the maximum percentage yield, loading efficiency and percentage (%) drug release compared to other formulations due to the incorporation of more amount of polymer compared to other formulations. SEM microphotographs and zeta-sizer reports indicated that atorvastatin-loaded chitosan nanoparticles were in the nanometric range and were spherical, discrete and uniform in size. The selected polymer chitosan was found to possess good compatibility with atorvastatin, without any mutual interaction, based on the results of DSC and FTIR analyses. The nanoparticles were found to have good flow properties. The in vivo results proved that the best formulation has shown significant difference in the reduction of triglycerides (TG), total cholesterol (TC) and no significant change in high density lipids (HDL) cholesterol levels in blood when compared with the marketed formulation. Better regenerative changes were observed during histopathological evaluation of liver in a group treated with atorvastatin nanoparticles than those of other groups, that confirmed the improved hypolipidemic action. Thus, from all the above observations, it was concluded that AN9 formulation has shown the highest in vitro drug release and loading efficiency than other formulations, which might be due to increased entrapment of drug and the surface area through decreased particle size which further confirmed the improved in vitro bioavailability and in vivo performance than those of marketed atorvastatin tablet. This study strongly suggests the use of chitosan nanoparticles as drug delivery system to improve the bioavailability of atorvastatin.

Physiologic Factors Affecting the Circulatory Persistence of Copolymer Microbubbles and Comparison of Contrast-Enhanced Effects between Copolymer Microbubbles and Sonovue

Ultrasound contrast agents have been widely used in clinical diagnosis. Knowledge of the physiologic factors affecting circulatory persistence is helpful in preparing long-lasting microbubbles (MBs) for blood perfusion and drug delivery research. In the study described here, we prepared copolymer MBs, compared their characteristics and contrast-enhanced effects with those of SonoVue and investigated the influence of external pressure, temperature, plasma components, renal microcirculation and cardiac motion on their circulatory persistence. The mean size of the copolymer MBs was 3.57 μm, larger than that of SonoVue. The copolymer MBs had longer circulatory persistence than SonoVue. At external pressures of 110 and 150 mm Hg, neither the quantity nor the morphology of the copolymer MBs changed. Further, their quantity and size were similar after incubation at 4°C and 39.4°C and when rabbit plasma and saline were compared. In vivo contrast-enhanced ultrasonography revealed a slightly larger area under the curve for the renal artery than for the renal vein. Thus, copolymer MBs exhibited good stability. However, the quantity of copolymer MBs decreased significantly after 180 s of circulation in an isolated toad heart perfusion model, indicating that cardiac motion was the main factor affecting their circulatory persistence.

A comparison of models for the analysis of the kinetics of drug release from PLGA-based nanoparticles

Purpose

Poly (lactic-co-glycolic acid) has received much academic attention for developing nanotherapeutics and FDA has approved it for several applications. An important parameter that dictates the bioavailability and hence the biological effect of the drug is drug release from its delivering system. This study offers a comparative mathematical analysis of drug release from Poly (lactic-co-glycolic acid)–based nanoparticles to suggest a general model explaining multi-mechanistic release they provide.

Methods

Eight release models, zero order, first order, Higuchi, Hixson-Crowell, the square root of mass, the three-second root of mass, Weibull and Korsmeyer-Peppas, as well as the second degree polynomial equation were applied to 60 data sets. The models analysed regarding several types of errors, regression parameters and average Akaike information criterion.

Results and discussion

Most of the data sets present the highest R², the lowest overall error and AIC for the Weibull model. Weibull model with the mean AIC = -36.37 and mean OE = 7.24 and the highest NE less than 5, 10, 15 and 20 % in most of the cases best fits the release data from various PLGA-based drug delivery systems that are studied. Weibull model seems to show enough flexibility to describe various release patterns PLGA provides.

Formulation of polymeric nanoparticles of antidepressant drug for intranasal delivery

Aim: The manuscript describes the performance of nanoparticles loaded with antidepressant drug for nose-to-brain drug delivery. Materials & methods: Poly-lactic-co-glycolic acid-loaded nanoparticles of agomelatine were prepared by nanoprecipitation method using poloxamer 407 as stabilizer. The process parameters were optimized using factorial design. Results: The drug-loaded nanoparticles having low particle size (<200 nm) with narrow size distribution and required zeta potential (-22.7 mV) to avoid aggregation showed sustained release profile and were found to have higher permeability as observed from ex vivo studies when compared with plain drug suspension. Histopathology test showed that the optimized formulation was free from nasal toxicity on the goat nasal mucosa. Pharmacodynamic study showed significant reduction in immobility time in rats treated with the formulation which indicated antidepressant activity of the formulation. Conclusion: The prepared agomelatin-loaded poly-lactic-co-glycolic acid nanoparticles showed prominent antidepressant activity by nose-to-brain delivery as observed from various studies.

Lipid-based nanocarrier efficiently delivers highly water soluble drug across the blood-brain barrier into brain

Delivering highly water soluble drugs across blood-brain barrier (BBB) is a crucial challenge for the formulation scientists. A successful therapeutic intervention by developing a suitable drug delivery system may revolutionize treatment across BBB. Efforts were given here to unravel the capability of a newly developed fatty acid combination (stearic acid:oleic acid:palmitic acid = 8.08:4.13:1) (ML) as fundamental component of nanocarrier to deliver highly water soluble zidovudine (AZT) as a model drug into brain across BBB. A comparison was made with an experimentally developed standard phospholipid-based nanocarrier containing AZT. Both the formulations had nanosize spherical unilamellar vesicular structure with highly negative zeta potential along with sustained drug release profiles. Gamma scintigraphic images showed both the radiolabeled formulations successfully crossed BBB, but longer retention in brain was observed for ML-based formulation (MGF) as compared to soya lecithin (SL)-based drug carrier (SYF). Plasma and brain pharmacokinetic data showed less clearance, prolonged residence time, more bioavailability and sustained release of AZT from MGF in rats compared to those data of the rats treated with SYF/AZT suspension. Thus, ML may be utilized to successfully develop drug nanocarrier to deliver drug into brain across BBB, in a sustained manner for a prolong period of time and may provide an effective therapeutic strategy for many diseases of brain. Further, many anti-HIV drugs cannot cross BBB sufficiently. Hence, the developed formulation may be a suitable option to carry those drugs into brain for better therapeutic management of HIV.

Gentamicin Sulfate PEG-PLGA/PLGA-H Nanoparticles: Screening Design and Antimicrobial Effect Evaluation toward Clinic Bacterial Isolates

Nanotechnology is a promising approach both for restoring or enhancing activity of old and conventional antimicrobial agents and for treating intracellular infections by providing intracellular targeting and sustained release of drug inside infected cells. The present paper introduces a formulation study of gentamicin loaded biodegradable nanoparticles (Nps). Solid-oil-in water technique was studied for gentamicin sulfate nanoencapsulation using uncapped Polylactide-co-glycolide (PLGA-H) and Polylactide-co-glycolide-co-Polyethylenglycol (PLGA-PEG) blends. Screening design was applied to optimize: drug payload, Nps size and size distribution, stability and resuspendability after freeze-drying. PLGA-PEG concentration resulted most significant factor influencing particles size and drug content (DC): 8 w/w% DC and 200 nm Nps were obtained. Stirring rate resulted most influencing factor for size distribution (PDI): 700 rpm permitted to obtain homogeneous Nps dispersion (PDI = 1). Further experimental parameters investigated, by 2³ screening design, were: polymer blend composition (PLGA-PEG and PLGA-H), Polyvinylalcohol (PVA) and methanol concentrations into aqueous phase. Drug content was increased to 10.5 w/w%. Nanoparticle lyophilization was studied adding cryoprotectants, polyvinypirrolidone K17 and K32, and sodiumcarboxymetylcellulose. Freeze-drying protocol was optimized by a mixture design. A freeze-dried Nps powder free resuspendable with stable Nps size and payload, was developed. The powder was tested on clinic bacterial isolates demonstrating that after encapsulation, gentamicin sulfate kept its activity.

Carboxylate cross-linked cyclodextrin: A nanoporous scaffold for enhancement of rosuvastatin oral bioavailability

Cyclodextrins play an important role in supramolecular chemistry acting as building blocks than can be cross-linked by various linker molecules forming nano-porous structures called nanosponges (NS). NS have the ability to enhance the stability, solubility and bioavailability of various actives. This work aimed at elaborating rosuvastatin (ROS) loaded NS to improve its oral bioavailability. Carboxylate-linked NS were synthesized by reacting β-CD with pyromellitic dianhydride (PDA) at different molar ratios under specific conditions. ROS-loaded NS were prepared by lyophilisation technique and characterized for particle size, zeta potential, entrapment efficiency and drug release. Occurrence of cross-linking and ROS incorporation within the NS were assessed by DSC, FT-IR and SEM micrographs. NS prepared at a molar ratio of 1:6 of β-CD: PDA demonstrated the highest entrapment efficiency (88.76%), an optimum particle size of 275nm, a narrow size distribution (PDI of 0.392), and zeta potential of -61.9 indicating good colloidal stability. In vivo oral pharmacokinetics study in male Sprague Dawley rats showed that ROS-NS provided an outstanding enhancement in oral bioavailability compared to drug suspension and marketed tablets besides their physicochemical stability for 3month. Accordingly, ROS-NS represent a superior alternative to the conventional marketed formulation for effective ROS delivery.

Paliperidone-Loaded Nanolipomer System for Sustained Delivery and Enhanced Intestinal Permeation: Superiority to Polymeric and Solid Lipid Nanoparticles

Paliperidone (PPD) is the most recent second-generation atypical antipsychotic approved for the treatment of schizophrenia. An immediate release dose causes extrapyramidal side effects. In this work, a novel nanolipomer carrier system for PPD with enhanced intestinal permeability and sustained release properties has been developed and optimized. PPD was successfully encapsulated into a lipomer consisting of a specific combination of biocompatible materials including poly-ε-caprolactone as a polymeric core, Lipoid S75, and Gelucire® 50/13 as a lipid shell and polyvinyl alcohol as a stabilizing agent. The lipomer system was characterized by dynamic light scattering, TEM, DSC, and FTIR. An optimized lipomer formulation possessed a particle size of 168 nm, PDI of 0.2, zeta potential of -23 mV and an encapsulation efficiency of 87.27% ± 0.098. Stability in simulated gastrointestinal fluids investigated in terms of particle size, zeta potential, and encapsulation efficiency measurements ensured the integrity of the nanoparticles upon oral administration. PPD-loaded nanolipomers demonstrated a superior sustained release behavior up to 24 h and better ex vivo intestinal permeation for PPD compared to the corresponding polymeric and solid lipid nanoparticles and drug suspension. The in vitro hemocompatibility test on red blood cells revealed no hemolytic effect of PPD-loaded lipomers which reflects its safety. The elaborated nanohybrid carrier system represents a promising candidate for enhancing the absorption of PPD providing a 2.6-fold increase in the intestinal permeation flux compared to the drug suspension while maintaining a sustained release behavior. It is a convenient alternative to the commercially available dosage form of PPD.

Brain Targeting of 1,9-Pyrazoloanthrone an c-Jun-N-terminal Kinase Inhibitor Using Liposomes for Effective Management of Parkinson's Disease

The major challenge to treat Parkinson's disease (PD) is penetration of target molecule into the brain to improve the efficacy of drugs. To achieve better brain penetration and targeted delivery, 1,9-Pyrazoloanthrone (1,9-P) loaded liposomes were developed by solvent injection technique using ultrasonication and evaluated for particle size, morphology, entrapment efficiency, FT-IR, and in-vitro drug release studies. The potential of 1,9-Pyrazoloanthrone (1,9-P), a c-Jun-N-terminal Kinase (JNK-3) inhibitor which could stop or retard the rate of apoptosis of neuronal cells was also evaluated. In-vivo pharmacokinetic and brain uptake studies of liposomes were performed to investigate the bioavailability and brain distribution of 1,9-P. Cytotoxicity and neuroprotection were done on SH-SY5Y cell line using MTT and AO/EB apoptosis assay. The optimized batch of liposomes showed an average size of 112.33 ± 0.84 nm with a zeta potential value of -19.40 mV and 78.96 ± 0.28% drug entrapment efficiency. The in-vitro release studies demonstrated the sustained release profile of liposome up to 24 h. The pharmacokinetic data in Wistar rats over the period of 12 h demonstrated 4.82-folds greater AUC_{(0-12 h)} for liposome in brain compared with 1,9-P suspension. Cytotoxicity assay showed no sign of toxicity, whereas apoptosis assay revealed a neuroprotective action of liposomes. The results demonstrated successful targeting of the 1,9-P, to brain as a novel strategy having significant therapeutic potential to treat PD.

Rationally designed nanocarriers for intranasaltherapy of allergic rhinitis: influence of carrier type on in vivo nasal deposition

The aim of this study is to develop a locally acting nasal delivery system of triamcinolone acetonide (TA) for the maintenance therapy of allergic rhinitis. The effect of encapsulating TA in different nanocarriers on its mucosal permeation and retention as well as in vivo nasal deposition has been studied. A comparative study was established between polymeric oil core nanocapsules (NCs), lipid nanocarriers such as nanoemulsion (NE), and nanostructured lipid carriers (NLCs). The elaborated nanocarriers were compared with TA suspension and the commercially available suspension "Nasacort(®)". The study revealed that NC provided the highest mucosal retention, as 46.14%±0.048% of the TA initial dose was retained after 24 hours, while showing the least permeation through the nasal mucosa. On the other hand, for TA suspension and Nasacort(®), the mucosal retention did not exceed 23.5%±0.047% of the initial dose after 24 hours. For NE and NLC, values of mucosal retention were 19.4%±0.041% and 10.97%±0.13%, respectively. NC also showed lower mucosal irritation and superior stability compared with NE. The in vivo nasal deposition study demonstrated that NC maintained drug in its site of action (nasal cavity mucosa) for the longest period of time. The elaborated polymeric oil core NCs are efficient carriers for the administration of nasally acting TA as it produced the least permeation results, thus decreasing systemic absorption of TA. Although NCs have been administered via various routes, this is the first study to implement the polymeric oil core NC as an efficient carrier for localized nasal drug delivery.

Biophysical characterization of small molecule antiviral-loaded nanolipogels for HIV-1 chemoprophylaxis and topical mucosal application

Nanocarriers are versatile vehicles for drug delivery, and emerging as platforms to formulate and deliver multiple classes of antiretroviral (ARV) drugs in a single system. Here we describe the fabrication of hydrogel-core and lipid-shell nanoparticles (nanolipogels) for the controlled loading and topical, vaginal delivery of maraviroc (MVC) and tenofovir disoproxil fumarate (TDF), two ARV drugs with different mechanisms of action that are used in the treatment of HIV. The nanolipogel platform was used to successfully formulate MVC and TDF, which produced ARV drug-loaded nanolipogels that were characterized for their physical properties and antiviral activity against HIV-1 BaL in cell culture. We also show that administration of these drug carriers topically to the vaginal mucosa in a murine model leads to antiviral activity against HIV-1 BaL in cervicovaginal lavages. Our results suggest that nanolipogel carriers are promising for the encapsulation and delivery of hydrophilic small molecule ARV drugs, and may expand the nanocarrier systems being investigated for HIV prevention or treatment.

STATEMENT OF SIGNIFICANCE

Topical, mucosal intervention of HIV is a leading strategy in the efforts to curb the spread of viral infection. A significant research thrust in the field has been to characterize different dosage forms for formulation of physicochemically diverse antiretroviral drugs. Nanocarriers have been used to formulate and deliver small molecule and protein drugs for a range of applications, including ARV drugs for HIV treatment. The broad significance of our work includes evaluation of lipid-shell, hydrogel-core nanoparticles for formulation and topical, vaginal delivery of two water-soluble antiretroviral drugs. We have characterized these nanocarriers for their physical properties and their biological activity against HIV-1 infection in vitro, and demonstrated the ability to deliver drug-loaded nanocarriers in vivo.

Polymeric nanoparticles containing diazepam: preparation, optimization, characterization, in-vitro drug release and release kinetic study

Nanoparticles formulated from biodegradable polymers like poly(lactic-co-glycolic acid) (PLGA) are being extensively investigated as drug delivery systems due to their two important properties such as biocompatibility and controlled drug release characteristics. The aim of this work to formulated diazepam loaded PLGA nanoparticles by using emulsion solvent evaporation technique. Polyvinyl alcohol (PVA) is used as stabilizing agent. Diazepam is a benzodiazepine derivative drug, and widely used as an anticonvulsant in the treatment of various types of epilepsy, insomnia and anxiety. This work investigates the effects of some preparation variables on the size and shape of nanoparticles prepared by emulsion solvent evaporation method. These nanoparticles were characterized by photon correlation spectroscopy (PCS), transmission electron microscopy (TEM). Zeta potential study was also performed to understand the surface charge of nanoparticles. The drug release from drug loaded nanoparticles was studied by dialysis bag method and the in vitro drug release data was also studied by various kinetic models. The results show that sonication time, polymer content, surfactant concentration, ratio of organic to aqueous phase volume, and the amount of drug have an important effect on the size of nanoparticles. Hopefully we produced spherical shape Diazepam loaded PLGA nanoparticles with a size range under 250 nm with zeta potential -23.3 mV. The in vitro drug release analysis shows sustained release of drug from nanoparticles and follow Korsmeyer-Peppas model.

Fabrication and in vivo evaluation of Nelfinavir loaded PLGA nanoparticles for enhancing oral bioavailability and therapeutic effect

Nelfinavir mesylate (NFV) is an anti-viral drug, used in the treatment of Acquired Immunodeficiency Syndrome (AIDS). Poor oral bioavailability and shorter half-life (3.5-5 h) remain a major clinical limitation of NFV leading to unpredictable drug bioavailability and frequent dosing. In this context, the objective of the present study was to formulate NFV loaded poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NPs), which can increase the solubility and oral bioavailability along with sustained release of the drug. NFV loaded PLGA-NPs were prepared by nanoprecipitation method using PLGA and Poloxomer 407. The prepared NPs were evaluated for particle size, zeta potential, morphology, drug content, entrapment efficiency (EE) and in vitro dissolution studies. Oral bioavailability studies were carried out in New Zealand rabbits by administering developed NFV PLGA-NPs and pure drug suspension. PLGA-NPs prepared by using 1:4 ratio of drug and PLGA, with a stirring rate of 1500 rpm for 4 h. The prepared NPs were in the size of 185 ± 0.83 nm with a zeta potential of 28.7 ± 0.09 mV. The developed NPs were found to be spherical with uniform size distribution. The drug content and EE of the optimized formulation were found to be 36 ± 0.19% and 72 ± 0.47% respectively. After oral administration of NFV PLGA-NPs, the relative bioavailability was enhanced about 4.94 fold compared to NFV suspension as a control. The results describe an effective strategy for oral delivery of NFV loaded PLGA NPs that helps in enhancing bioavailability and reduce the frequency of dosing.

pH triggered delivery of curcumin from Eudragit-coated chitosan microspheres for inflammatory bowel disease: characterization and pharmacodynamic evaluation

OBJECTIVE

This investigation deals with the development and evaluation (in vitro and in vivo) of pH triggered Eudragit-coated chitosan microspheres of curcumin (CUR) for treating ulcerative colitis.

METHODS

CUR-loaded chitosan microspheres were initially prepared by emulsion cross linking method followed by coating with Eudragit S-100. The pharmacodynamics of the developed formulation was analyzed in mice by acetic acid induced colitis model.

RESULTS

The developed microspheres were of uniform spherical shape with high entrapment efficiency. CUR-chitosan microspheres showed less intense peaks compared to free CUR confirming inclusion of drug within microspheres as revealed by X-ray diffractogram. Uncoated CUR-chitosan microspheres exhibited burst release within initial 4 h while microspheres coated with Eudragit S-100 prevented premature release of CUR and showed controlled release up to 12 h following Higuchi model. In vivo organ biodistribution study showed negligible amount of CUR in stomach and small intestine confirming integrity of microsphere in upper gastrointestinal tract (GIT). In vivo study revealed significant reduction in severity and extent of colonic damage with CUR-loaded microspheres as compared to pure CUR which was further confirmed by histopathological study.

CONCLUSION

In vitro and in vivo studies proved the developed formulations as a promising system for pH-dependent delivery of drug to colon in ulcerative colitis.