Biosynthesis, Characterization, and Wound-Healing Activity of Phenytoin-Loaded Copper Nanoparticles.

Wound-healing is a very complex and evolutionary process that involves a great variety of dynamic steps. Although different pharmaceutical agents have been developed to hasten the wound-healing process, the existing agents are still far from optimal. The present work aimed to prepare and evaluate the wound-healing efficacy of phenytoin-loaded copper nanoparticles (PHT-loaded CuNPs). CuNPs were biosynthesized using licorice aqueous extract. The prepared CuNPs were loaded with PHT by adsorption, characterized, and evaluated for wound-healing efficiency. Results showed that both plain and PHT-loaded CuNPs were monodisperse and exhibited a cubic and hexagonal morphology. The mechanism by which PHT was adsorbed on the surface of CuNPs was best fit by the Langmuir model with a maximum loaded monolayer capacity of 181 mg/g. The kinetic study revealed that the adsorption reaction followed the pseudo-second order while the thermodynamic parameters indicated that the adsorption process was physical in nature and endothermic, and occurred spontaneously. Moreover, the in vivo wound-healing activity of PHT-loaded CuNP impregnated hydroxypropylmethyl cellulose (HPMC) gel was carried out using an excisional wound model in rats. Data showed that PHT-loaded CuNPs accelerated epidermal regeneration and stimulated granulation and tissue formation in treated rats compared to controls. Additionally, quantitative real-time polymerase chain reaction (RT-PCR) analysis showed that lesions treated with PHT-loaded CuNPs were associated with a marked increase in the expression of dermal procollagen type I and a decrease in the expression of the inflammatory JAK3 compared to control samples. In conclusion, PHT-loaded CuNPs are a promising platform for effective and rapid wound-healing.

Oil-entrapped ranitidine HCl beads heal peptic ulcers via local and systemic mechanisms.

OBJECTIVE: Oral gastroretentive system is one of the site-specific drug delivery system, which is designed to be retained in upper GIT for a prolonged time. Ranitidine hydrochloride (RHCl), which is used frequently in treatment of peptic ulcer, is a suitable candidate for gastroretentive delivery systems. Dependently, floating oil-entrapped alginate beads of RHCl were developed and evaluated as an approach to site-specific delivery avoiding colonic degradation and enhancing both bioavailability and the proposed local effect. METHODS: Different formulations of floating beads were suggested and randomized using 24 full factorial design. Optimized formulation was subjected for in vivo studies to measure the oral bioavailability and the healing effect of induced peptic ulcers. RESULTS: Beads size ranged from 1.32 to 2.3 mm. All beads revealed excellent floating capabilities. Optimum formulation (F12) has entrapment efficiency of 70%, drug loading of 7% and 71% RHCl released after 6 h. SEM of F12 shows a grossly spherical structure with presence of oil droplets distributed throughout structure. AUC obtained from F12 was nonsignificantly higher than that of a commercial tablet. Signs of ulcer healing appeared clearly with F12 through appearance of granulation tissue, collagen fibers and newly formed blood vessels. Healing rate and extent obtained with a commercial tablet were less than F12. Quantitative analysis confirmed histopathological findings. CONCLUSION: Floating oil-entrapped beads are a promising approach for RHCl delivery to remain in stomach for a longer time ensuring site-specific delivery and consequently, enhancing local healing effect of peptic ulcers.

Solubilization and Enhancement of Ex Vivo Vaginal Delivery of Progesterone Using Solid Dispersions, Inclusion Complexes and Micellar Solubilization.

BACKGROUND: Progesterone (PG), a natural female sex hormone is used clinically in menopausal hormone replacement therapy and to control reproductive functions. Its very limited aqueous solubility results in reduced oral bioavailability and low patient compliance when administered in high doses. The aim of this study was to enhance PG aqueous solubility and vaginal delivery using solid dispersion, inclusion complex and micellar solubilization techniques. METHODS: PG solid dispersions and inclusion complexes were prepared by solvent evaporation method using different polymers, such as cyclodextrins, polyvinyl pyrrolidone (PVP), poly (ethylene glycol) 6000, Pluronic® F-127 and Pluronic® F-68. PG was also incorporated into polymeric micelles of Pluronic® F-127, Pluronic® F- 68, Brij®35 and Myrj®52. The prepared solid dispersions, inclusion complexes and micelles were characterized using different techniques. Drug permeability across rabbit vaginal mucosa was also studied. RESULTS: Dissolution studies of PG solid dispersions showed that the highest drug dissolution rate was achieved at PG/polymer weight ratio of 5:5. Further, complete drug dissolution was obtained for PG/Pluronic® F-127 solid dispersion after 15 min compared to 42% dissolution for the drug alone. Brij®35 micelles had a drug loading capacity ~15%, which increased the drug aqueous solubility by more than 20 folds. PG permeability coefficients through rabbit vaginal mucosa for PG/Brij®35 micelles and PG/Pluronic® F-127 micelles were ~ two times higher than that of the drug alone. CONCLUSION: These results confirm that Brij®35 and Pluronic® F-127 micelles are promising carriers to overcome PG shortcomings through enhancing its aqueous solubility and vaginal permeability.

Mucoadhesive tablets for the vaginal delivery of progesterone: in vitro evaluation and pharmacokinetics/pharmacodynamics in female rabbits.

OBJECTIVE: To develop mucoadhesive tablets for the vaginal delivery of progesterone (P4) to overcome its low oral bioavailability resulting from drug hydrophobicity and extensive hepatic metabolism. METHODS: The tablets were prepared using mixtures of P4/Pluronic® F-127 solid dispersion and different mucoadhesive polymers. The tablets physical properties, swelling index, mucoadhesion and drug release kinetics were evaluated. P4 pharmacokinetic and pharmacodynamic properties were evaluated in female rabbits and compared with vaginal micronized P4 tablets and intramuscular (IM) P4 injection, respectively. RESULTS: The tablets had satisfactory physical properties and their swelling, in vitro mucoadhesion force and ex vivo mucoadhesion time were dependent on tablet composition. Highest swelling index and mucoadhesion time were detected for tablets containing 20% chitosan-10% alginate mixture. Most tablets exhibited burst release (∼25%) during the first 2 h but sustained the drug release for ∼48 h. In vivo study showed that chitosan-alginate mucoadhesive tablets had ∼2-fold higher P4 mean residence time (MRT) in the blood and 5-fold higher bioavailability compared with oral P4. Further, same tablets showed 2-fold higher myometrium thickness in rabbit uterus compared with IM P4 injection. CONCLUSION: These results confirm the potential of these mucoadhesive vaginal tablets to enhance P4 efficacy and avoid the side effects associated with IM injection.