Ahmed M. Samy

Silymarin loaded liposomes for hepatic targeting: In vitro evaluation and HepG2 drug uptake

Silymarin has hepatoprotective properties and is used in treatment of various liver diseases, but its bioavailability from oral products is very poor. In order to overcome its poor oral bioavailability we have prepared silymarin loaded hepatic targeting liposomes suitable for parenteral administration. The liposomal formulations were composed of hydrogenated soy phosphatidylcholine and cholesterol with or without distearoylphosphoethanolamine-(polyethyleneglycol)-2000 and various amounts of β-sitosterol β-D-glucoside (Sito-G) as the hepatic targeting moiety. Increasing the amount of Sito-G in the liposomes gradually decreased drug encapsulation efficiencies from ∼70% to ∼60%; still showing promising drug encapsulation efficiencies. Addition of Sito-G to non-PEGylated liposomes clearly affected their drug release profiles and plasma protein interactions, whereas no effect on these was seen for the PEGylated liposomes. Non-PEGylated liposomes with 0.17 M ratio of Sito-G exhibited the highest cellular drug uptake of 37.5% for all of the studied liposome formulations. The highest cellular drug uptake in the case of PEGylated liposomes was 18%, which was achieved with 0.17 and 0.33 M ratio of added Sito-G. The liposome formulations with the highest drug delivery efficacy in this study showed hemolytic activities around 12.7% and were stable for at least 2 months upon storage in 20 mM HEPES buffer (pH 7.4) containing 1.5% Polysorbate 80 at 4 °C and room temperature. These results suggest that the Sito-G containing liposomes prepared in this work have hepatic targeting capability and that they are promising candidates for delivering silymarin to the liver.

Response surface methodology for the development of self-nanoemulsified drug delivery system (SNEDDS) of all-trans-retinol acetate.

The purpose was to prepare, characterize, and optimize a self-nanoemulsified drug delivery system (SNEDDS) of a model lipophilic compound, all-trans-retinol acetate. As part of the optimization process, the main effects, interaction effects, and quadratic effects of the formulation ingredients were investigated. Method. A three-factor, three-level Box-Behnken design was used to explore the quadratic response surfaces and construct a second-order polynomial model in the form: Y = A + A1X1+ A2X2+ A3X3+ A4X1X2+ A5X2X3+ A6X1X3+ A7X12+ A8X22+ A9X32+ E. Amount of added oil (X1), surfactant (X2), and cosurfactant (X3) were selected as the factors. Particle size (Y1), turbidity (Y2), and cumulative amount of the active ingredient emulsified after 10 (Y3) and 30 (Y4) min were the observed variables. Response surface plots were used to demonstrate the effect of factors (X1), (X2), and (X3) on the response (Y4). Amount of added soybean oil (X1), Cremophor EL (X2), and Capmul MCM-C8 (X3) showed a significant effect on the emulsification rates, as well as on the physical properties of the resultant emulsion (particle size and turbidity). Observed and predicted values of Y4 obtained from the constructed equations were in close agreement. Response surface methodology was then used to predict the levels of factors X1, X2, and X3 under the constrained variables for an optimum response. Applied constraints were 0 < Y1 < 0.5, 1 < Y2 < 20, 60 < Y3 < 80, and 90 < Y4 < 100. The predicted values were 0.0704 µm for particle size (Y1), 18.95 NTU for turbidity (Y2), 88.88% for drug release after 10 min (Y3), and 110.7% drug release after 30 min (Y4). Two new formulations were prepared according to the predicted levels. The observed and predicted values were in close agreement.

Development of biodegradable in situ implant and microparticle injectable formulations for sustained delivery of haloperidol

The objective of this study is to formulate injectable, biodegradable sustained release in situ implant (ISI), and in situ microparticle (ISM) formulations of haloperidol. Factors affecting the in vitro drug release, pharmacokinetics, and stability of the formulations were investigated. The concentration of the polymer, poly(lactide-co-glycolide) acid (PLGA), and the type of solvents showed a pronounced effect on the in vitro drug release from the ISI and ISM formulations. The ISM formulation [20% PLGA in N-methyl-2-pyrrolidone (NMP)-peanut oil, 1:4] showed reduced maximum plasma concentration (60 versus 44 ng/mL) and longer release (30 days, plasma concentration of 8 ng/mL versus 20 days, plasma concentration of 6 ng/mL) compared with the ISI formulation (20% PLGA in NMP) after intramuscular injection in rats. The delivery of haloperidol can be extended further by changing the concentration, molecular weight, and lactide-to-glycolide ratio of the PLGA. These formulations can be easily administered by both intramuscular and subcutaneous injections. The shelf lives of both systems were found to be 2 years when stored at 4°C. Haloperidol can be formulated as an injectable ISI or ISM systems suitable for 1 month or longer release.

In vitro release, rheological, and stability studies of mefenamic acid coprecipitates in topical formulations

A suitable topical formulation of mefenamic acid was developed in order to eliminate the gastrointestinal disorders associated with its oral administration. Drug coprecipitates prepared with different polymers at various drug-to-polymer ratios improved drug solubility and dissolution compared to pure drug and physical mixtures. PVP polymers (ratio 1:4) produced the best results. Aqueous ionic cream, ointments of absorption and water soluble bases and gels of methylcellulose, carboxymethylcellulose sodium, HPMC, Carbopol® 934 and 940, and Pluronic® F127 bases containing 1–10% drug as coprecipitates of PVP polymers (1:4) were prepared. The highest drug release was achieved at 1% drug concentration from water soluble base and methylcellulose among cream/ointment and gel bases, respectively. Gels, in general yielded better release than creams/ointments. All tested medicated creams/ointments exhibited plastic flow while all gels conformed to pseudoplasticity. Most of them showed thixotropy, a desired property of topical preparations. Stability studies revealed that HPMC and methylcellulose had the smallest changes in drug content, viscosity, and pH among the formulations. Considering drug release, rheological properties, and stability, methylcellulose gel containing 1% drug as coprecipitates of PVP K90 was the best among the studied formulations, was promising for improving bioavailability of mefenamic acid and can be used in future studies.

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

Abstract 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 (Cmax), time to achieve Cmax 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.

Mucoadhesive controlled release microcapsules of indomethacin: Optimization and stability study

The aim of this project was to develop and optimize indomethacin microcapsules composed of multiple mucoadhesive polymers for high drug entrapment, good mucoadhesiveness and drug release in a controlled fashion over a longer period of time. Microcapsules containing sodium alginate, sodium carboxymethylcellulose, methylcellulose, Carbopol® 934 and hydroxypropyl methylcellulose were prepared by orifice-ionic gelation method. The effects of composition of microcapsules on drug entrapment efficacy, drug release and mucoadhesive character were determined by mixture statistical design. Most formulations exhibited good mucoadhesive property in everted intestinal sac test. Drug entrapment efficiency (68–94%) was dependent on the type of polymers. Drug release (92–100%) extended over 12 h. The optimized formulation resulted in drug entrapment efficiency of 89.3%, drug release of 94.8% and mucoadhesiveness of 30.4%. All formulations were stable for more than 1.5 years. The optimized mucoadhesive microcapsules are promising for controlled delivery of indomethacin with twice a day oral administration.

Influence of Hydroalcoholic Vehicle on In Vitro Transport of 4-Hydroxy Tamoxifen Through the Mammary Papilla (Nipple)

Majority of breast cancers originate from epithelial cells in the duct and lobules in the breast. Current systemic treatments for breast cancer are associated with significant systemic side effects, thus warranting localized drug delivery approaches. The aim of this study was to investigate the influence of hydroalcoholic vehicle on topical delivery of 4-hydroxy tamoxifen (4-HT) through the mammary papilla (nipple). The in vitro permeability of 4-HT through porcine mammary papilla was studied using different hydroalcoholic vehicles (0, 33.33, and 66.66% alcohol). Nile red was used as a model lipophilic dye to characterize the drug transport pathway in the mammary papilla. The penetration of 4-HT through the mammary papilla increased with increase in alcohol concentration in the vehicle. The solubility of 4-HT was enhanced by increasing alcohol concentration in the vehicle. On the other hand, the epidermis/vehicle partition coefficient decreased with increase in alcohol concentration. The mammary papilla served as a depot and slowly released 4-HT into the receptor medium. Highest drug penetration was observed with saturated drug solution in 66.66% alcohol, and 4-HT levels were comparable to IC50 value of 4-HT. Results from this study demonstrate the possibility of using mammary papilla as a potential route for direct delivery of 4-HT to the breast.

Optimization and evaluation of lyophilized fenofibrate nanoparticles with enhanced oral bioavailability and efficacy

Abstract The objective of this study was to enhance physiochemical properties as well as oral bioavailability of the poorly water soluble drug fenofibrate (FB), through preparation of amorphous solid dispersions (ASDs). ASDs were prepared via freeze drying using polyvinylpyrrolidone (PVP) K30 and poloxamer 188 as hydrophilic carriers. Formulations were optimized by 32 full factorial design (FFD) with PVP-K30 level (X1) and poloxamer 188 level (X2) as independent variables and particle size (Y1), zeta potential (Y2), drug content (Y3) and dissolution rate (T90, [Y4]) as dependent variables. Optimized FB nanoparticles were physicochemically evaluated and formulated into lyophilized sublingual tablets. Pharmacokinetic, pharmacodynamics and histological finding of optimized formulation were performed on rabbits. Y1 and Y4 were significantly affected by independent variables while Y2 and Y3 were not affected. Physicochemical characterization showed the drug was in amorphous state, nanometer range and pharmacophore of FB was preserved. Administration of optimized FB tablets to rabbits with fatty liver led to significant reduction (p < 0.001) in serum lipids. Moreover, histological analysis of liver specimens confirmed the improved efficacy in animals with fatty liver. In this study, we confirmed that ASDs of FB had beneficial effects on managing fatty liver and serum lipids level in hyperlipidemic rabbits.

Development and optimisation of atorvastatin calcium loaded self-nanoemulsifying drug delivery system (SNEDDS) for enhancing oral bioavailability: in vitro and in vivo evaluation

Abstract The objective of this study was to develop and optimise self-nanoemulsifying drug delivery system (SNEDDS) of atorvastatin calcium (ATC) for improving dissolution rate and eventually oral bioavailability. Ternary phase diagrams were constructed on basis of solubility and emulsification studies. The composition of ATC–SNEDDS was optimised using the Box–Behnken optimisation design. Optimised ATC–SNEDDS was characterised for various physicochemical properties. Pharmacokinetic, pharmacodynamic and histological findings were performed in rats. Optimised ATC–SNEDDS resulted in droplets size of 5.66 nm, zeta potential of −19.52 mV, t90 of 5.43 min and completely released ATC within 30 min irrespective of pH of the medium. Area under the curve of optimised ATC–SNEDDS in rats was 2.34-folds higher than ATC suspension. Pharmacodynamic studies revealed significant reduction in serum lipids of rats with fatty liver. Photomicrographs showed improvement in hepatocytes structure. In this study, we confirmed that ATC–SNEDDS would be a promising approach for improving oral bioavailability of ATC.

Tolmetin Sodium loaded thermosensitive mucoadhesive liquid suppositories for rectal delivery; strategy to overcome oral delivery drawbacks

Abstract Tolmetin sodium (TS) is a nonsteroidal anti-inflammatory drug (NSAID) indicated for treatment of musculoskeletal issues. As other NSAID, TS displays a marked side effects on the gastro-intestinal (GI) tract after oral administration. Traditional solid suppositories can cause pain and discomfort for patients, may reach the end of the colon; consequently, the drug can undergo the first-pass effect. TS liquid suppository (TS-LS) was developed to enhance patient compliance and rectal mucosal safety in high-risk patients receiving highly NSAID therapy. This work was conducted to optimize and evaluate Poloxamer P407/P188-based thermoresponsive TS-LS by using mucoadhesive polymers such as methylcellulose (MC). TS-LS was prepared by cold method and characterized their in vitro physicochemical properties as gelation temperature (GT), gel strength, bioadhesive properties, and in vitro release. The safety of the prepared suppository on rectum, stomach, and liver was evaluated histologically. Pharmacokinetic analyses were performed to compare rectal TS-LS to orally Rhumtol® capsules. The results showed that the optimized TS-LS; composed of P407/P188/MC (21/9/0.5% w/w) displayed gelation at rectum temperature ∼32.90 °C, gel strength of 21.35 s and rectal retention force at the administration site of 24.25 × 102 dyne/cm2. Moreover, TS-LS did not cause any morphological damage to the rectal tissues. Pharmacokinetic parameters of optimized TS-LS formulation revealed 4.6 fold increase in bioavailability as compared to Rhumtol® capsules. Taken together, the results demonstrated that liquid suppository is a potential and physically safe rectal delivery carrier for improvement rectal bioavailability and in vivo safety of TS.