Mahasen Mohamed Meshali

Vorinostat with sustained exposure and high solubility in poly(ethylene glycol)-b-poly(dl-lactic acid) micelle nanocarriers: Characterization and effects on pharmacokinetics in rat serum and urine

The histone deacetylase inhibitor suberoylanilide hydroxamic acid, known as vorinostat, is a promising anticancer drug with a unique mode of action; however, it is plagued by low water solubility, low permeability, and suboptimal pharmacokinetics. In this study, poly(ethylene glycol)-b-poly(DL-lactic acid) (PEG-b-PLA) micelles of vorinostat were developed. Vorinostats pharmacokinetics in rats was investigated after intravenous (i.v.) (10 mg/kg) and oral (p.o.) (50 mg/kg) micellar administrations and compared with a conventional polyethylene glycol 400 solution and methylcellulose suspension. The micelles increased the aqueous solubility of vorinostat from 0.2 to 8.15 ± 0.60 and 10.24 ± 0.92 mg/mL at drug to nanocarrier ratios of 1:10 and 1:15, respectively. Micelles had nanoscopic mean diameters of 75.67 ± 7.57 and 87.33 ± 8.62 nm for 1:10 and 1:15 micelles, respectively, with drug loading capacities of 9.93 ± 0.21% and 6.91 ± 1.19%, and encapsulation efficiencies of 42.74 ± 1.67% and 73.29 ± 4.78%, respectively. The micelles provided sustained exposure and improved pharmacokinetics characterized by a significant increase in serum half-life, area under curve, and mean residence time. The micelles reduced vorinostat clearance particularly after i.v. dosing. Thus, PEG-b-PLA micelles significantly improved the p.o. and i.v. pharmacokinetics and bioavailability of vorinostat, which warrants further investigation.

Effect of gel composition and phonophoresis on the transdermal delivery of ibuprofen: In vitro and in vivo evaluation

The objective of this study was to evaluate the effect of formulation composition and continuous ultrasound at 1.5 W/Cm2 intensity on the permeation of ibuprofen across polymeric and biological barriers. In vitro studies were performed using cellulose membrane and rabbit skin, whereas in vivo studies were performed on rabbits. Overall, higher transport data were obtained with the cellulose membrane. Nonetheless, with both barriers, transport was higher with the gel formulation than oleaginous or emulsion based preparations, which was also dependent on the viscosity of the gel and the concentration of the formulation additives. Transport increased with the increase in alcohol concentration and decreased with the addition of propylene glycol. Ultrasound had a significant effect on ibuprofen transport. For example, an 11-fold increase in drug permeation across cellulose membrane was observed after the application of ultrasound. Similar effect was observed in animal studies. Ibuprofen plasma concentration increased with the concentration of the drug in the gel, which significantly increased after the application of ultrasound. It was concluded that aqueous gel formulations act as ideal coupling agents for topical application of drugs. Nonetheless, in addition to ultrasound, the composition of the gel is expected to have a significant effect on the transdermal delivery of drugs.

Ion-exchange complex of famotidine: sustained release and taste masking approach of stable liquid dosage form.

A stable controlled release resinate-complex for the highly bitter taste famotidine (FAM) was developed to allow once-daily administration and improve patient compliance especially in pediatric and geriatric medicine. The drug-resinate complexes were prepared in different drug to resin (Amberlite IRP-69) ratios by weight (1:1, 1:2, 1:3, 1:4, 1:5 and 1:6). The optimized drug-resinate complex resulted from 1:6 drug to resin ratio experienced maximum drug loading and sustained release property. Hence, it was subjected to physicochemical characterizations by differential scanning colorimetry (DSC), x-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). The optimized complex was further dispensed in the prepared syrup and the suspension was subjected to accelerated stability study, as mentioned in the International Conference on Harmonization (ICH) guidelines. Furthermore, the gustatory properties of the complex were evaluated on humans. The syrup complied successfully with ICH guidelines and sufficiently alleviated the bitterness of famotidine.

Improvement of dissolution and hypoglycemic efficacy of glimepiride by different carriers.

Effects of tromethamine (Tris), polyvinylpyrrolidone (PVP-K25), and low molecular weight chitosan (LM-CH) on dissolution and therapeutic efficacy of glimepiride (Gmp) were investigated using physical mixtures (PMs), coground mixtures, coprecipitates (Coppts) or kneaded mixtures (KMs), and compared with drug alone. Fourier transform infrared spectroscopy, differential scanning colorimetry, and X-ray diffractometry were performed to identify any physicochemical interaction with Gmp. Surface morphology was examined via scanning electron microscopy. The results of Gmp in vitro dissolution revealed that it was greatly enhanced by Coppt with Tris or PVP-K25 and KM with LM-CH at a drug to carrier ratio of 1:8. Gmp amorphization by PVP-K25 and LM-CH was a major factor in increasing Gmp dissolution. Being basic, Tris might increase the pH of the microdiffusion layer around Gmp particles improving its dissolution. Formation of water-soluble complexes suggested by solubility study may also explain the enhanced dissolution. Capsules were prepared from Coppts and KM 1:8 drug to carrier binary systems and also with Tris PMs. In vivo, the hypoglycemic efficacy of Gmp capsules in rabbits increased by 1.63-, 1.50-, and 1.46-fold for 1:8 Coppts with Tris or PVP-K25 and KM with LM-CH respectively, compared with Gmp alone. Surprisingly, the response to Tris PM 1:20 capsules was 1.52-fold revealing statistically insignificant difference to that of Tris Coppt 1:8 (1.63 fold). As a conclusion, dissolution enhancement and hypoglycemic potentiation by 1:20 PM of Gmp/Tris, being simple and easy to prepare, may enable development of a reduced-dose and fast-release oral dosage form of Gmp.

Novel anti-inflammatory film as a delivery system for the external medication with bioactive phytochemical “Apocynin”

Purpose Recently, Apocynin (APO) has emerged as a bioactive phytochemical with potent antioxidant and anti-inflammatory properties. No reports have been published so far concerning its topical application as a pharmaceutical dosage form for prospective use. To the best of our knowledge, this is the first study to fabricate novel anti-inflammatory film for external medication with APO. Methods APO film was prepared using casein (CAS) as a natural protein film former by solvent casting technique. The medicated film was extensively evaluated in terms of its various physicochemical characteristics, ex vivo skin permeation profile, stability, and finally in vivo anti-inflammatory activity on carrageenan-induced rat paw edema. Results The film represented satisfactory mechanical properties along with good flexibility. Fourier transform-infrared spectroscopy, differential scanning calorimetry, and X-ray diffractometry revealed possible solubility of APO in the amorphous CAS and inter- and intramolecular hydrogen bonding between the film components. The ex vivo skin permeation results of the medicated film demonstrated non-Fickian diffusion mechanism of the permeated drug. Application of APO film to rat paw before carrageenan-induced paw edema or after induction disclosed eminent anti-inflammatory activity expressed by marked decrease in paw swelling (%) and increase in edema inhibition rate (%). In addition, histopathologic examination revealed a significant decrease in inflammatory scores. The immunohistochemical expression levels of both nuclear factor kappa B and cyclooxygenase-2 were significantly suppressed. Conclusion These results indicated that CAS film could be applied as a promising external delivery system for the anti-inflammatory APO.

New in-situ gelling biopolymer-based matrix for bioavailability enhancement of glimepiride; in-vitro/in-vivo x-ray imaging and pharmacodynamic evaluations

Abstract Glimepiride (Gmp) a third generation of sulphonylurea is a weakly acidic hypoglycemic drug that belongs to Biopharmaceutical Classification System (BCS) class II. It suffers from poor solubility as well as erratic and variable therapeutic effect. The authors investigated the feasibility of utilizing two nontoxic and biodegradable biopolymers (casein (CA) and chitosan (CT)) as a new in-situ gelling tablet matrix to circumvent this limitation. Both polymers in different ratios were combined with constant dose of the drug and compressed by direct compression to produce constant weights of different tablet matrices. Basic tromethamine (Tris) was also included in each matrix as a pH modifier. Swelling indices, rheological properties of the swollen matrices, and their in-vitro drug release in simulating gastric fluid were assessed. The higher the ratio of casein in the tablet matrix, the lower its swelling index and the higher its viscosity indicate a shear thickening property. Intuitively, zero order drug diffusion in 0.1 N HCl prevailed for more than 8 hours from this gelled matrix. Both reduction of blood glucose level up till 11 hours and x-ray imaging of the selected tablets in the GIT of rabbits correlated well with the shear thickening properties. These findings propose a new stable, simple and affordable price matrix with large versatility.

Novel chitosan-based solid-lipid nanoparticles to enhance the bio-residence of the miraculous phytochemical “Apocynin”

ABSTRACT Apocynin (APO), a specific NADPH oxidase inhibitor, is a bioactive phytochemical that exhibits versatile pharmacological activities. However, its rapid elimination and poor bioavailability represent great challenges to pharmaceutical scientists. Accordingly, novel chitosan‐based APO‐loaded solid lipid nanoparticles (CS,APO ‐ loaded SLNS) were developed to address such obstacles. A full 24 factorial design of experiment approach was employed to evaluate the individual and combined effect of critical process parameters namely; the amount of glycerol tristearate (GTS, XA) and sucrose mono palmitate (SMP, XB) as well as the concentration of chitosan (CS, XC) and polyvinyl alcohol (PVA, XD), on different critical quality attributes. Full characterization and extensive in vitro‐in vivo evaluations of the optimized SLNs formula were conducted. The optimized formula, with core (CS,APO) and shell (PVA), has enhanced oral and intravenous bioavailability in rats as clearly verified when compared with APO solution. Probably, PVA hindered opsonization intravenously and SLNs reduced pre‐systemic effect. In conclusion, the novel chitosan‐based SLNs system would open new vistas in potentiating the bioavailability and sustaining the effect of APO and other bioactive phytochemicals with comparable properties.