Assessment of Binary Agarose-Carbopol Buccal Gels for Mucoadhesive Drug Delivery: Ex Vivo and In Vivo Characterization.

Agarose (AG) is a naturally occurring biocompatible marine seaweed extract that is converted to hydrocolloid gel in hot water with notable gel strength. Currently, its mucoadhesion properties have not been fully explored. Therefore, the main aim of this study was to evaluate the mucoadhesive potential of AG binary dispersions in combination with Carbopol 934P (CP) as mucoadhesive gel preparations. The gels fabricated via homogenization were evaluated for ex vivo mucoadhesion, swelling index (SI), dissolution and stability studies. The mucoadhesive properties of AG were concentration dependent and it was improved by the addition of CP. Maximum mucoadhesive strength (MS) (27.03 g), mucoadhesive flow time (FT) (192.2 min), mucoadhesive time in volunteers (MT) (203.2 min) and SI (23.6% at 4 h) were observed with formulation F9. The mucoadhesive time investigated in volunteers (MT) was influenced by AG concentration and was greater than corresponding FT values. Formulations containing 0.3%, w/v AG (F3 and F9) were able to sustain the release (~99%) for both drugs till 3 h. The optimized formulation (F9) did not evoke any inflammation, irritation or pain in the buccal cavity of healthy volunteers and was also stable up to 6 months. Therefore, AG could be considered a natural and potential polymer with profound mucoadhesive properties to deliver drugs through the mucosal route.

Simple and high sample throughput LC/ESI-MS/MS method for bioequivalence study of prazosin, a drug with risk of orthostatic hypotension.

OBJECTIVE: The study aimed to develop a rapid, simple and sensitive LC/ESI-MS/MS method to measure prazosin concentration in human plasma and apply bedside sampling in bioequivalence study of two prazosin tablets to resolve the adverse effect of orthostatic hypotension. SIGNIFICANCE: The LC/ESI-MS/MS prazosin method was highly sensitive and selective. Bedside sampling reduced the orthostatic hypotension incidence and subject dropout rate. METHODS: After sample preparation, prazosin and terazosin (IS) were detected on mass spectrometer operating in multiple reaction monitoring mode using positive ionization. Mobile phase flow rate was set at 0.40 mL/min with sample run time of 1.75 min. The bioanalytical method was validated as per EMEA and FDA guidelines. Bedside sampling was performed in bioequivalence study for the first 4 h after dosing. The three primary pharmacokinetic parameters, Cmax, AUC0-t and AUC0-∞ and 90% confidence interval were determined. RESULTS: The small injection volume of 1 µL minimized instrumentation contamination and prolonged the analytical column lifespan. Linearity was obtained between 0.5 and 30.0 ng/mL, with coefficient of determination, r2 ≥ 0.99. The mean extraction recovery of prazosin and IS was >92%, with precision value (CV, %) ≤ 10.3%. Only two orthostatic hypotension adverse events were reported. The two prazosin formulations were found to be bioequivalent. CONCLUSION: The LC/ESI-MS/MS method has shown robustness and reliability exemplified by the incurred sample re-analysis result. Bedside sampling should be proposed for bioequivalence or pharmacokinetic studies of drugs demonstrating adverse event of orthostatic hypotension.

Novel Curcumin-Encapsulated α-Tocopherol Nanoemulsion System and Its Potential Application for Wound Healing in Diabetic Animals.

Objective: This project was aimed at formulating a novel nanoemulsion system and evaluating it for open incision wound healing in diabetic animals. Methods: The nanoemulsions were characterized for droplet size and surface charge, drug content, antioxidant and antimicrobial profiling, and wound healing potential in diabetic animals. The skin samples excised were also analyzed for histology, mechanical strength, and vibrational and thermal analysis. Results: The optimized nanoemulsion (CR-NE-II) exhibited droplet size of26.76 ± 0.9 nm with negative surface charge (-10.86 ± 1.06 mV), was homogenously dispersed with drug content of68.05 ± 1.2%, released almost82.95 ± 2.2%of the drug within first 2 h of experiment with synergistic antioxidant (95 ± 2.1%) and synergistic antimicrobial activity against selected bacterial strains in comparison to blank nanoemulsion, and promoted significantly fast percent reepithelization (96.47%). The histological, vibrational, thermal, and strength analysis of selected skin samples depicted a uniform and even distribution of collagen fibers which translated into significant increase in strength of skin samples in comparison to the control group. Conclusions: The optimized nanoemulsion system significantly downregulated the oxidative stress, enhanced collagen deposition, and precluded bacterial contamination of wound, thus accelerating the skin tissue regeneration process.

Glimepiride-Loaded Nanoemulgel; Development, In Vitro Characterization, Ex Vivo Permeation and In Vivo Antidiabetic Evaluation.

Glimepiride (GMP), an oral hypoglycemic agent is extensively employed in the treatment of type 2 diabetes. Transdermal delivery of GMP has been widely investigated as a promising alternative to an oral approach but the delivery of GMP is hindered owing to its low solubility and permeation. The present study was designed to formulate topical nanoemulgel GMP system and previously reported solubility enhanced glimepiride (GMP/ßCD/GEL-44/16) in combination with anti-diabetic oil to enhance the hypoglycemic effect. Nanoemulsions were developed using clove oil, Tween-80, and PEG-400 and were gelled using xanthan gum (3%, w/w) to achieve the final nanoemulgel formulations. All of the formulations were evaluated in terms of particle size, zeta potential, pH, conductivity, viscosity, and in vitro skin permeation studies. In vivo hypoglycemic activity of the optimized nanoemulgel formulations was evaluated using a streptozocin-induced diabetes model. It was found that a synergistic combination of GMP with clove oil improved the overall drug permeation across the skin membrane and the hypoglycemic activity of GMP. The results showed that GMP/ßCD/GEL-44/16-loaded nanoemulgel enhanced the in vitro skin permeation and improved the hypoglycemic activity in comparison with pure and marketed GMP. It is suggested that topical nano emulsion-based GMP gel and GMP/ßCD/GEL-44/16 could be an effective alternative for oral therapy in the treatment of diabetes.

Improved Bioavailability of Ebastine through Development of Transfersomal Oral Films.

The main objective of this research work was the development and evaluation of transfersomes integrated oral films for the bioavailability enhancement of Ebastine (EBT) to treat allergic rhinitis. The flexible transfersomes, consisting of drug (EBT), lipid (Phosphatidylcholine) and edge activator (EA) Polyoxyethylene sorbitan monooleate or Sorbitan monolaurate, were prepared with the conventional thin film hydration method. The developed transfersomes were further integrated into oral films using the solvent casting method. Transfersomes were evaluated for their size distribution, surface charge, entrapment efficiency (EE%) and relative deformability, whereas the formulated oral films were characterized for weight, thickness, pH, folding endurance, tensile strength, % of elongation, degree of crystallinity, water content, content uniformity, in vitro drug release and ex vivo permeation, as well as in vivo pharmacokinetic and pharmacodynamics profile. The mean hydrodynamic diameter of transfersomes was detected to be 75.87 ± 0.55 nm with an average PDI and zeta potential of 0.089 ± 0.01 and 33.5 ± 0.39 mV, respectively. The highest deformability of transfersomes of 18.52 mg/s was observed in the VS-3 formulation. The average entrapment efficiency of the transfersomes was about 95.15 ± 1.4%. Transfersomal oral films were found smooth with an average weight, thickness and tensile strength of 174.72 ± 2.3 mg, 0.313 ± 0.03 mm and 36.4 ± 1.1 MPa, respectively. The folding endurance, pH and elongation were found 132 ± 1, 6.8 ± 0.2 and 10.03 ± 0.4%, respectively. The ex vivo permeability of EBT from formulation ETF-5 was found to be approximately 2.86 folds higher than the pure drug and 1.81 folds higher than plain film (i.e., without loaded transfersomes). The relative oral bioavailability of ETF-5 was 2.95- and 1.7-fold higher than that of EBT-suspension and plain film, respectively. In addition, ETF-5 suppressed the wheal and flare completely within 24 h. Based on the physicochemical considerations, as well as in vitro and in vivo characterizations, it is concluded that the highly flexible transfersomal oral films (TOFs) effectively improved the bioavailability and antihistamine activity of EBT.

Formulation development and in vitro characterization of triple layer tablet containing amlodipine besylate, rosuvastatin calcium and hydrochlorothiazide.

Triple layered tablet having various excipients and a new combination of APIs i.e. amlodipine besylate, rosuvastatin calcium and hydrochlorothiazide was prepared through wet granulation. The concentration of disintegrant and diluent was kept different in formulations of all APIs. At compression stage, nine different formulations from H1 to H9 having different combinations were prepared. Layers T1, T2 and T3 of all the three APIs had disintegrant concentration of 3%, 5% and 7 % respectively. In vitro analysis of granules was made by determining angle of repose, loss on drying, bulk density, tapped density, hausner ratio. Results of all these parameters were quite similar in all layers, which showed that change in disintegrant concentration does not affect the flow ability of granules to much extent. After compression, tablets were further subjected to weight variation, hardness, thickness, friability, disintegration, dissolution studies and FTIR. In vitro drug release data of all formulations were studied which showed that all the formulations exhibited zero order release. Results indicated that H8 had the best results in terms of physicochemical properties, assay and dissolution studies. The external morphology of formulations were further analyzed using scanning electron microscopy and differential scanning calorimetry. Triple layered tablet was successfully developed and characterized.

Poloxamer-188 and d-α-Tocopheryl Polyethylene Glycol Succinate (TPGS-1000) Mixed Micelles Integrated Orodispersible Sublingual Films to Improve Oral Bioavailability of Ebastine; In Vitro and In Vivo Characterization.

Orodispersible sublingual films (OSFs) composed of hydrophilic polymers were loaded with poloxamer-188 and d-α-tocopheryl polyethylene glycol succinate (TPGS-1000) mixed micelles to improve the oral bioavailability of a poorly soluble drug, ebastine (EBT). Mixed micelles formed by thin-film hydration method were incorporated into orodispersible sublingual film, consisting of HPMC and glycerol, using solvent casting technique. The mixed micelles and films were thoroughly evaluated for physicochemical characterization (size, polydispersity index, zeta potential, entrapment efficiency, thickness, weight, surface pH studies, disintegration time, swelling indices, mechanical properties, FTIR, PXRD, DSC, SEM, AFM, in vitro drug release, in vivo bioavailability, and toxicological studies). The results showed that the average particle size of mixed micelles was 73 nm. The mean zeta potential and PDI of the optimal mixed micelles formulation were -26 mV and 0.16, respectively. Furthermore, the maximum entrapment efficiency 82% was attained. The film's disintegration time was in the range of 28 to 102 s in aqueous media. The integrity of micelles was not affected upon incorporation in films. Importantly, the micelles-loaded films revealed rapid absorption, high permeability, and increased bioavailability of EBT as compared to the pure drug. The existence of ebastine loaded mixed micelles in the films enhanced the bioavailability about 2.18 folds as compared to pure drug. Further, the results evidently established in-vitro and in-vivo performance of bioavailability enhancement, biocompatibility, and good safety profile of micelles-loaded orodispersible EBT films. Finally, it was concluded that film loaded with poloxamer-188/TPGS-1000 mixed micelles could be an effective carrier system for enhancing the bioavailability of ebastine.

Effect of Hydrophilic Polymers on Complexation Efficiency of Cyclodextrins in Enhancing Solubility and Release of Diflunisal.

The effects of three hydrophilic polymers, namely, carboxymethyl cellulose sodium (CMC-Na), polyvinyl alcohol (PVA) and poloxamer-188 (PXM-188) on the solubility and dissolution of diflunisal (DIF) in complexation with ß-cyclodextrin (ßCD) or hydroxypropyl ß-cyclodextrin (HPßCD), were investigated. The kneading method was used at different drug to cyclodextrin weight ratios. Increases in solubility and drug release were observed with the DIF/ßCD and DIF/HPßCD complexes. The addition of hydrophilic polymers at 2.5, 5.0 and 10.0% w/w markedly improved the complexation and solubilizing efficiency of ßCD and HPßCD. Fourier-transform infrared (FTIR) showed that DIF was successfully included into the cyclodextrin cavity. Differential scanning calorimetry (DSC) and X-ray diffractometry (XRD) confirmed stronger drug amorphization and entrapment in the molecular cage of cyclodextrins. The addition of PVA, CMC-Na or PXM-188 reduced further the intensity of the DIF endothermic peak. Most of the sharp and intense peaks of DIF disappeared with the addition of hydrophilic polymers. In conclusion, PXM-188 at a weight ratio of 10.0% w/w was the best candidate in enhancing the solubility, stability and release of DIF.

Evaluation of solubility and dissolution of lamotrigine using lipid based microparticulate carriers: An in-vitro analysis.

The present study was designed to develop novel lipid microparticles in order to improve solubility, dissolution and bioavailability of a lipophilic drug of BCS class II, lamotrigine. For that purpose, increase in solubility of the model drug was investigated using different lipids and the promising lipids were further used for the fabrication of microparticles. Solid lipid (GMS) and liquid lipid (olive oil) were used along with an emulsifier (Tween 80) and a stabilizer (Poloxamer 188) to prepare mircoparticles by melt emulsification method. Prepared formulations were characterized for physicochemical properties such as solubility, particle size, zeta potential, polydispersity index and entrapment efficiency. In vitro dissolution studies were carried out in 0.01 N HCl for 24 h. The findings provided that the solubility of lamotrigine was reasonably increased in GMS, olive oil, Tween 80 and poloxamer 180. The lamotrigine solubility was increased 4.92 fold with G4 microparticles formulation. Size analysis revealed that the microparticles were in range of 11.1 to 178.8 µm and the zeta potential values were from -13 to -20 mV. Microparticles prepared with solid and liquid lipids exhibited satisfactory entrapment efficiency ranging from 59 to 87%. Conclusively, the outcomes of the studies suggest the appropriateness of selected ingredients for improving solubility as well as loading of lamotrigine in microparticles for its sustained and effective delivery.

Stability indicating RP-HPLC method of dexibuprofen in nanocream formulation: Identification and quantification.

A stability indicating reverse phase-HPLC method was designed for determination of dexibuprofen in drug solution and in nanocream formulation. Chromatographic conditions were optimized simply by adjusting the content and different compositions of reverse phase associated with mobile phases. Different parameters like specificity, limit of quantification (LOQ), limit of detection, linearity, range, system suitability, precision and accuracy were determined. Stability studies of dexibuprofen in nanocream were taken under the stressed situations of alkali, acid, oxidation process, UV and heat degradation. Tailing factor and % RSD were found >2000 and <2% respectively. The method was identified linear over the range of 0.2-1.6mg/ml having co-efficient of correlation 0.9995. Intra-day and inter- day precision and accuracy values for dexibuprofen were < 0.6% and <1.1032 and < 0.3% and 1.10% respectively. Stability studies showed that dexibuprofen was stable in nanocream against alkali, acid, oxidation, UV light and heat. The developed validated method was precise and accurate for the evaluation of dexibuprofen in solution as well as in nanocream formulation.

Improvement of solubility and dissolution of ebastine by fabricating phosphatidylcholine/ bile salt bilosomes.

Although ebastine (EBT) can impede histamine-induced skin allergic reaction and persuade long acting selective H1 receptor antagonistic effects but its poor water solubility circumscribed its clinical application. The main objective of this research work was to improve the aqueous solubility and oral bioavailability of EBT by preparing EBT-loaded bilosomes (EBT-PC-SDC-BS). A thin film hydration method was used to prepare ebastine loaded bilosomes. The prepared-formulations were optimized considering size, morphology and entrapment efficiency. The SEM images revealed regular and spherical shape of bilosomes. Average size of the prepared EBT-PC-SDC-BS was 665.8 nm and zeta potential was around-32.9 mV with 89.05 % average entrapment efficiency (EE).Importantly, the solubility of EBT in water was amplified up to 17.9 µg/ml compared to pure drug (2 µg/mL) reflecting a highest solubility increase of 751 %. In vitro drug release results of prepared EBT-PC-SDC-BS exhibited improved release behavior. Finally, it is established from the results that the EBT-PC-SDC-BS could function as a favorable nano-carrier system to improve the solubility as well as dissolution of EBT.

Binary inclusion complexes of diflunisal with ß-cyclodextrin and hydroxypropyl-ß-cyclodextrin: Preparation and characterization.

Low aqueous solubility and bioavailability is the limiting factor to achieve desired therapeutic efficacy for variety of new and existing drug moieties. The goal of the present study was to explore the effects of ß-cyclodextrin (ßCD) and hydroxypropyl-ß-cyclodextrin (HPßCD) on the solubility and dissolution profile of diflunisal (DIF) prepared by using two different methods (physical mixing and solvent evaporation) at DIF-cyclodextrins weight ratios of 1:1, 1:2 and 1:4. The phase solubility studies demonstrated that DIF solubility increased proportionally with an increase in ßCD and HPßCD concentration. The inclusion complexes were subjected to characterization of scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and X-ray diffractometry (XRD). Solvent evaporation yielded higher DIF solubility than physical mixing method. HPßCD-DIF inclusion complexes yielded higher dissolution profile than ßCD complexes when prepared under same experimental design. FTIR, DSC and XRD confirmed the successful inclusion of DIF into cyclodextrin (ßCD/HPßCD) by both preparation methods with enhanced water solubility and drug release in comparison with pure drug.

Polymer blend: a new approach for eliminating curing effect of aqueous dispersion coatings

The aim of present work was to investigate blends of Eudragit® NE 30D with Aquacoat® ECD using different ratios to eliminate curing effect associated with individual polymers. Propranolol HCl 10% w/w was layered onto sugar cores using 5% w/w HPMC as a binder. Drug-layered-cores were coated either with pure or blends of Aquacoat® ECD: Eudragit® NE 30D in a fluidized bed coater to obtain 20% w/w coating level. Talc 35% w/w was used as anti-tacking agent. The pellets were characterized for in vitro dissolution studies, morphology, water uptake-weight loss, osmolality and adhesion of coating after curing at 60 °C or 60 °C/75% RH for 24 h. The findings revealed that Aquacoat® ECD coated pellets showed curing effect due to further gradual coalescence of polymeric particles which resulted into better film formation upon curing. In contrast, the curing effect of Eudragit® NE 30D coated pellets was caused by decrease in adhesion of coatings after curing which provided entirely different swelling behavior of uncured (localized swelling) and cured (uniform swelling) pellets. The undesired curing effect of individual polymers was eliminated by using their blends in appropriate ratio.

Stability indicating HPLC-UV method for detection of curcumin in Curcuma longa extract and emulsion formulation.

A stability-indicating HPLC-UV method for the determination of curcumin in Curcuma longa extract and emulsion was developed. The system suitability parameters, theoretical plates (N), tailing factor (T), capacity factor (K'), height equivalent of a theoretical plate (H) and resolution (Rs) were calculated. Stress degradation studies (acid, base, oxidation, heat and UV light) of curcumin were performed in emulsion. It was found that N>6500, T<1.1, K' was 2.68-3.75, HETP about 37 and Rs was 1.8. The method was linear from 2 to 200 µg/mL with a correlation coefficient of 0.9998. The intra-day precision and accuracy for curcumin were ⩽0.87% and ⩽2.0%, while the inter-day precision and accuracy values were ⩽2.1% and ⩽-1.92. Curcumin degraded in emulsion under acid, alkali and UV light. In conclusion, the stability-indicating method could be employed to determine curcumin in bulk and emulsions.