Yousry, C., M. M. Amin, A. H. Elshafeey, and O. N. Elgazayerly, "Ultrahigh verapamil-loaded controlled release polymeric beads using superamphiphobic substrate: D-optimal statistical design, in vitro and in vivo performance.", Drug delivery, vol. 25, issue 1, pp. 1448-1460, 2018 Nov. Abstractultrahigh_verapamil_loaded_controlled_release_polymeric_beads_using_superamphiphobic_substrate_d_optimal_statistical_design_in_vitro_and_in_vivo.pdf

Controlled-release multiparticulate systems of hydrophilic drugs usually suffer from poor encapsulation and rapid-release rate. In the present study, ultra-high loaded controlled release polymeric beads containing verapamil hydrochloride (VP) as hydrophilic model drug were efficiently prepared using superamphiphobic substrates aiming to improve patient compliance by reducing dosing frequency. Superamphiphobic substrates were fabricated using clean aluminum sheets etched with ammonia solution and were treated with 1.5% (w/v) perfluorodecyltriethoxysilane (PFDTS) alcoholic solution. The effect of the main polymer type (lactide/glycolide (PLGA) 5004A, PLGA 5010, and polycaprolactone (PCL)), copolymer (Eudragit RS100) content together with the effect of drug load on encapsulation efficiency (EE%) and in vitro drug release was statistically studied and optimized via D-optimal statistical design. In vivo pharmacokinetic study was carried out to compare the optimized system relative to the market product (Isoptin). Results revealed that superamphiphobic substrates were successfully prepared showing a rough micro-sized hierarchical structured surface upon observing with scanning electron microscope and were confirmed by high contact angles of 151.60 ± 2.42 and 142.80°±05.23° for water and olive oil, respectively. The fabricated VP-loaded beads showed extremely high encapsulation efficiency exceeding 92.31% w/w. All the prepared systems exhibited a controlled release behavior with Q12 h ranging between 5.46 and 95.90%w/w. The optimized VP-loaded system composed of 150 mg (1.5% w/v) PCL without Eudragit RS100 together with 160 mg VP showed 2.7-folds mean residence time compared to the market product allowing once daily administration instead of three times per day.

Yousry, C., S. A. Elkheshen, H. M. El-Laithy, T. Essam, and R. H. Fahmy, "Studying the influence of formulation and process variables on Vancomycin-loaded polymeric nanoparticles as potential carrier for enhanced ophthalmic delivery.", European journal of pharmaceutical sciences , vol. 100, pp. 142-154, 2017 Jan 13. Abstract

Ocular topically applied Vancomycin (VCM) suffers poor bioavailability due to its high molecular weight and hydrophilicity. In the present investigation, VCM-loaded polymeric nanoparticles (PNPs) were developed aiming to enhance its ocular bioavailability through prolonging its release pattern and ophthalmic residence. PNPs were prepared utilizing double emulsion (W/O/O), solvent evaporation technique. 2(3)×4(1) full factorial design was applied to evaluate individual and combined influences of polymer type, Eudragit® RS100, sonication time, and Span®80 concentration on PNPs particle size, encapsulation efficiency, and zeta potential. Further, the optimized formulae were incorporated in 1% Carbopol®-based gel. In-vivo evaluation of the optimized formulae was performed via Draize test followed by microbiological susceptibility testing on albino rabbits. Results revealed successful formulation of VCM-loaded PNPs was achieved with particle sizes reaching 155nm and up to 88% encapsulation. Draize test confirmed the optimized formulae as non-irritating and safe for ophthalmic administration. Microbiological susceptibility testing confirmed prolonged residence, higher Cmax. with more than two folds increment in the AUC(0.25-24) of VCM-PNPs over control groups. Thus, VCM-loaded PNPs represent promising carriers with superior achievements for enhanced Vancomycin ophthalmic delivery over the traditional use of commercially available VCM parenteral powder after constitution into a solution by the ophthalmologists.

Yousry, C., R. H. Fahmy, T. Essam, H. M. El-Laithy, and S. A. Elkheshen, "Nanoparticles as tool for enhanced ophthalmic delivery of vancomycin: a multidistrict-based microbiological study, solid lipid nanoparticles formulation and evaluation.", Drug development and industrial pharmacy, vol. 42, issue 11, pp. 1752-1762, 2016 Apr 19. Abstract

CONTEXT: A microbiological multidistrict-based survey from different Egyptian governorates was conducted to determine the most prevalent causative agents of ocular infections in the Egyptian population. Antibiotic sensitivity testing was then performed to identify the most potent antimicrobial agent. Vancomycin (VCM) proved the highest activity against gram-positive Staphylococcus bacteria, which are the most commonly isolated causative agents of ocular infection. However, topically applied VCM suffers from poor ocular bioavailability because of its high molecular weight and hydrophilicity.

OBJECTIVE: The aim of the present study was to develop VCM-loaded solid lipid nanoparticles (SLNs) using water-in-oil-in-water (W/O/W) double emulsion, solvent evaporation technique to enhance ocular penetration and prolong ophthalmic residence of VCM.

METHOD: Two consecutive full factorial designs (2(4) followed by 3(2)) were adopted to study the effect of different formulation and process parameters on SLN formulation. The lipid type and structure, polyvinyl alcohol (PVA) molecular weight and concentration, sonication time, as well as lipid:drug ratio were studied as independent variables. The formulated SLN formulae were evaluated for encapsulation efficiency (EE%), particle size (PS), and zeta potential as dependent variables.

RESULTS: The statistically-optimized SLN formula (1:1 ratio of glyceryltripalmitate:VCM with 1% low molecular weight PVA and 1 min sonication time) had average PS of 277.25 nm, zeta potential of -20.45, and 19.99% drug encapsulation. Scanning and transmission electron micrographs showed well-defined, spherical, homogenously distributed particles.

CONCLUSION: The present study suggests that VCM incorporation into SLNs is successfully achievable; however, further studies with different nanoencapsulation materials and techniques would be valuable for improving VCM encapsulation.