Oral bioavailability enhancement of doxazosin mesylate: Nanosuspension versus self-nanoemulsifying drug delivery systems.

Background and purpose: Doxazosin mesylate (DOX) is an antihypertensive drug that possesses poor water solubility and, hence, poor release properties. Both nanosuspensions and self-nanoemulsifying drug delivery systems (SNEDDS) are becoming nanotechnology techniques for the enhancement of water solubility of different drugs. Experimental approach: The study's goal was to identify the best drug delivery system able to enhance the release and antihypertensive effect of DOX by comparing the physical characteristics such as particle size, zeta potential, entrapment efficiency, release rate, and main arterial blood pressure of DOX-loaded nanosuspensions and SNEDDS in liquid and solid form. Key results: DOX nanosuspension preparation had a particle size of 385±13 nm, poly-dispersity index of 0.049±3, zeta potential of 50 ± 4 mV and drug release after 20 min (91±0.43 %). Liquid SNEDDS had a droplet size of 224±15 nm, poly-dispersity index of (0.470±0.01), zeta potential of -5±0.10 mV and DR20min of 93±4 %. Solid SEDDS showed particle size of 79±14 nm, poly-dispersity index of 1±0.00, a zeta potential of -18 ±0.26 mv and DR20min of 100 ±2.72 %. Conclusion: Finally, in terms of the mean arterial blood pressure lowering, solid SNEDDS performed better effect than both liquid SNEDDS and nanosuspension (P >0.05).

Tailoring Risperidone-Loaded Glycethosomal In Situ Gels Using Box-Behnken Design for Treatment of Schizophrenia-Induced Rats via Intranasal Route.

Schizophrenic patients often face challenges with adherence to oral regimens. The study aimed to highlight the potentiality of intranasal ethanol/glycerin-containing lipid-nanovesicles (glycethosomes) incorporated into in situ gels for sustaining anti-psychotic risperidone (RS) release. The Box-Behnken Design (BBD) was followed for in vitro characterization. Glycethosomal-based in situ gels were examined by physical, ex vivo, and in vivo investigations. The ethanol impact on minimizing the vesicle size (VS) and enhancing the zeta potential (ZP) and entrapment efficiency (EE%) of nanovesicles was observed. Glycerin displayed positive action on increasing VS and ZP of nanovesicles, but reduced their EE%. After incorporation into various mucoadhesive agent-enriched poloxamer 407 (P407) in situ gels, the optimized gel containing 20% P407 and 1% hydroxypropyl methyl cellulose-K4M (HPMC-K4M) at a 4:1 gel/glycethosomes ratio showed low viscosity and high spreadability with acceptable pH, gel strength, and mucoadhesive strength ranges. The ethanol/glycerin mixture demonstrated a desirable ex vivo skin permeability of RS through the nasal mucosa. By pharmacokinetic analysis, the optimized gel showed eight-fold and three-fold greater increases in RS bioavailability than the control gel and marketed tablet, respectively. Following biochemical assessments of schizophrenia-induced rats, the optimized gel boosted the neuroprotective, anti-oxidant, and anti-inflammatory action of RS in comparison to other tested preparations. Collectively, the intranasal RS-loaded glycethosomal gel offered a potential substitute to oral therapy for schizophrenic patients.

Optimization of Potential Nanoemulgels for Boosting Transdermal Glimepiride Delivery and Upgrading Its Anti-Diabetic Activity.

Transdermal drug delivery has been widely adopted as a plausible alternative to the oral route of administration, especially for drugs with poor systemic bioavailability. The objective of this study was to design and validate a nanoemulsion (NE) system for transdermal administration of the oral hypoglycemic drug glimepiride (GM). The NEs were prepared using peppermint/bergamot oils as the oil phase and tween 80/transcutol P as the surfactant/co-surfactant mixture (Smix). The formulations were characterized using various parameters such as globule size, zeta potential, surface morphology, in vitro drug release, drug-excipient compatibility studies, and thermodynamic stability. The optimized NE formulation was then incorporated into different gel bases and examined for gel strength, pH, viscosity, and spreadability. The selected drug-loaded nanoemulgel formulation was then screened for ex vivo permeation, skin irritation, and in vivo pharmacokinetics. Characterization studies revealed the spherical shape of NE droplets with an average size of ~80 nm and a zeta potential of -11.8 mV, which indicated good electrokinetic stability of NE. In vitro release studies revealed enhanced drug release from the NE formulation compared to the plain drug. GM-loaded nanoemulgel showed a 7-fold increment in drug transdermal flux compared to plain drug gel. In addition, the GM-loaded nanoemulgel formulation did not elicit any signs of inflammation and/or irritation on the applied skin, suggesting its safety. Most importantly, the in vivo pharmacokinetic study emphasized the potential of nanoemulgel formulation to potentiate the systemic bioavailability of GM, as manifested by a 10-fold rise in the relative bioavailability compared to control gel. Collectively, transdermal NE-based GM gel might represent a promising alternative to oral therapy in the management of diabetes.

Development of depot PLGA-based in-situ implant of Linagliptin: Sustained release and glycemic control.

High percentage of diabetic people are diagnosed as type 2 who require daily dosing of an antidiabetic drug such as Linagliptin (Lina) to manage their blood glucose levels. This study aimed to develop injectable Lina-loaded biodegradable poly (lactic-co-glycolic acid) (PLGA) in-situ implants (ISIs) to deliver a desired burst effect of Lina followed by a sustained release over several days for controlling the blood glucose levels over prolonged time periods. The morphological, pharmacokinetic, and pharmacodynamic assessments of the Lina-loaded ISIs were performed. Scanning electron microscopy (SEM) study revealed the rapid exchange between the water miscible solvent (N-methyl-2-pyrrolidone; NMP) and water during the ISI preparation, hence enhancing the initial burst Lina release. While, triacetin of lower water affinity could lead to formation of more compact and dense ISI structure with slower drug release. By comparing various ISI formulations containing different solvents and different PLGA concentrations, the ISI containing 40 % PLGA and triacetin was selected for its sustained release of Lina (93.06 ± 1.50 %) after 21 days. The pharmacokinetic results showed prolonged half life (t1/2) and higher area under the curve (AUC) values of the selected Lina-loaded ISI when compared to those of oral Lina preparation. The single Lina-ISI injection produced a hypoglycemic control in the diabetic rats very similar to the daily oral administration of Lina after 7 and 14 days. In conclusion, PLGA-based ISIs confirmed their suitability for prolonging Lina release in patients receiving long-term antidiabetic therapy, thereby achieving more enhanced patient compliance and reduced dosing frequency.

Brain-targeted delivery of Valsartan using solid lipid nanoparticles labeled with Rhodamine B; a promising technique for mitigating the negative effects of stroke.

The brain is a vital organ that is protected from the general circulation and is distinguished by the presence of a relatively impermeable blood brain barrier (BBB). Blood brain barrier prevents the entry of foreign molecules. The current research aims to transport valsartan (Val) across BBB utilizing solid lipid nanoparticles (SLNs) approach to mitigate the adverse effects of stroke. Using a 32-factorial design, we could investigate and optimize the effect of several variables in order to improve brain permeability of valsartan in a target-specific and sustained-release manner, which led to alleviation of ischemia-induced brain damage. The impact of each of the following independent variables was investigated: lipid concentration (% w/v), surfactant concentration (% w/v), and homogenization speed (RPM) on particle size, zeta potential (ZP), entrapment efficiency (EE) %, and cumulative drug release percentage (CDR) %. TEM images revealed a spherical form of the optimized nanoparticles, with particle size (215.76 ± 7.63 nm), PDI (0.311 ± 0.02), ZP (-15.26 ± 0.58 mV), EE (59.45 ± 0.88%), and CDR (87.59 ± 1.67%) for 72 hours. SLNs formulations showed sustained drug release, which could effectively reduce the dose frequency and improve patient compliance. DSC and X-ray emphasize that Val was encapsulated in the amorphous form. The in-vivo results revealed that the optimized formula successfully delivered Val to the brain through intranasal rout as compared to a pure Val solution and evidenced by the photon imaging and florescence intensity quantification. In a conclusion, the optimized SLN formula (F9) could be a promising therapy for delivering Val to brain, alleviating the negative consequences associated with stroke.

Formulation and evaluation of fast dissolving tablets of haloperidol solid dispersion.

Purpose: The aim of this study was to design fast dissolving tablets (FDT) of the anti -psychiatric drug haloperidol in solid dispersion forms as a way to enhance its dissolution profile and anti-psychiatric effect. Methods: Solubility studies of haloperidol in various polymers solutions were investigated. The selected polymer with high drug solubility (Poly ethylene glycol 4000) was used for preparation of solid dispersion through two methods solvent evaporation method and melting method. Haloperidol solid dispersion mixed with other solid powder excipients and compressed into tablets. The resulted tablets were evaluated according to British Pharmacopoeia (B.P.) specifications. Pre- and post -compression studies were performed to determine the flow properties and evaluate the solid dispersion systems, followed by in vivo studies through forced swimming test (FST). Results: Pre-compression studies showed adequate flowability and compatibility of polymer and solid excipients with haloperidol. The selected solid dispersion tablet (SD2) demonstrated the best disintegration and water absorption ratio in addition to satisfactory friability and hardness. Attempts of in vitro dissolution results and thermodynamic stability studies showed acceptable results for (SD2) formulation containing PEG 4000 polymer prepared by melting method.The in vivo study of (SD2) formulation revealed the highest immobility time to rats compared to control rats and others treated with commercial haloperidol product. Conclusion: Fast dissolving tablets prepared from solid dispersion of haloperidol with PEG4000 expressed rapid onset of action with enhanced anti-psychiatric effect of haloperidol.

Investigation of Alogliptin-Loaded In Situ Gel Implants by 23 Factorial Design with Glycemic Assessment in Rats.

The aim of the study was to design injectable long-acting poly (lactide-co-glycolide) (PLGA)-based in situ gel implants (ISGI) loaded with the anti-diabetic alogliptin. Providing sustained therapeutic exposures and improving the pharmacological responses of alogliptin were targeted for achieving reduced dosing frequency and enhanced treatment outputs. In the preliminary study, physicochemical characteristics of different solvents utilized in ISGI preparation were studied to select a proper solvent possessing satisfactory solubilization capacity, viscosity, water miscibility, and affinity to PLGA. Further, an optimization technique using a 23 factorial design was followed. The blood glucose levels of diabetic rats after a single injection with the optimized formulation were compared with those who received daily oral alogliptin. N-methyl-2-pyrrolidone (NMP) and dimethyl sulfoxide (DMSO), as highly water-miscible and low viscous solvents, demonstrated their effectiveness in successful ISGI preparation and controlling the burst alogliptin release. The impact of increasing lactide concentration and PLGA amount on reducing the burst and cumulative alogliptin release was represented. The optimized formulation comprising 312.5 mg of PLGA (65:35) and DMSO manifested a remarkable decrease in the rats' blood glucose levels throughout the study period in comparison to that of oral alogliptin solution. Meanwhile, long-acting alogliptin-loaded ISGI systems demonstrated their feasibility for treating type 2 diabetes with frequent dosage reduction and patient compliance enhancement.

Transdermal ethosomal gel nanocarriers; a promising strategy for enhancement of anti-hypertensive effect of carvedilol.

The current study was conducted to develop vesicular ethosomal gel (ethogel) systems for upgrading the transdermal delivery of anti-hypertensive carvedilol. Ethosomes composed of Phospholipon 100 H, cholesterol, ethanol, and Transcutol P at different ratios, were prepared by thin-film hydration method with sonication. Carvedilol-loaded ethosomes were characterized by microscopic examinations followed by other in-vitro assessments. Selected ethosomal formulation (E10) was incorporated into different concentrations of gelling agents to prepare the ethogel formulations. Ethogels were subjected to physicochemical characterization, compatibility, and in-vitro drug release studies. Ex-vivo skin permeation and retention studies were performed followed by in-vivo studies in induced hypertensive rats. The smooth ethosomes demonstrated vesicular size of 201.55-398.55 nm, entrapment efficiency of 30.00-90.66% and loading capacity of 7.64-43.04% with zeta potential range of -30.30 to -44.90 mV. The homogeneous ethogels exhibited appropriate results of pH and drug content measurements. Spreadability was observed as a function of viscosity as the latter increased, the former decreased. The ethogel formulation (G2) manifested satisfactory physical appearance, spreadability, viscosity, and in-vitro release. In comparison to pure carvedilol gel, tested formulations (E10 and G2) developed high ex-vivo permeation, steady-state flux and drug retention through skin layers. The in-vivo study of G2 formulation revealed a significant gradual decline (p < 0.01) in the mean arterial pressure of rats at the second hour of experiment (146.11 mmHg) with continuous significant decrease (p < 0.001) after 6 h (98.88 mmHg). In conclusion, ethogels as promising lipid carriers proved their potential to enhance skin permeation with extended anti-hypertensive action of carvedilol.

Injectable PLGA Adefovir microspheres; the way for long term therapy of chronic hepatitis-B.

For patient convenience, sustained release Adefovir Poly-d,l-lactic-co-glycolic acid (PLGA) microspheres were formulated to relieve the daily use of the drug which is a problem for patients treated from chronic hepatitis-B. PLGA microspheres were prepared and characterized by entrapment efficiency, particle size distribution and scanning electron microscopy (SEM). In-vitro release and in-vivo studies were carried out. Factors such as drug: polymer ratio, polymer viscosity and polymer lactide content were found to be important variables for the preparation of PLGA Adefovir microspheres. Fourier transform infrared (FTIR) analysis and differential scanning calorimetry (DSC) were performed to determine any drug-polymer interactions. One way analysis of variance (ANOVA) was employed to analyze the pharmacokinetic parameters after intramuscular injection of the pure drug and the selected PLGA microspheres into rats. FTIR and DSC revealed a significant interaction between the drug and the polymer. Reports of SEM before and after 1 and 24 h release showed that the microspheres had nonporous smooth surface even after 24 h release. The entrapment efficiency ranged between 55.83 and 86.95% and in-vitro release studies were continued for 16, 31 and 90 days. The pharmacokinetic parameters and statistical analysis showed a significant increase in the Tmax, AUC0-t and MRT, and a significant decrease in the Cmax of the tested formulation (p < 0.05). Results demonstrated that PLGA Adefovir microspheres could be used for long-term treatment of chronic hepatitis-B instead of the daily dose used by the patient.

Upgrading of dissolution and anti-hypertensive effect of Carvedilol via two combined approaches: self-emulsification and liquisolid techniques.

OBJECTIVE: The aim of the study was to design a self-emulsifying drug delivery system (SEDDS) of the anti-hypertensive Carvedilol in liquid and liquisolid forms as a way to enhance its dissolution profile and anti-hypertensive effect. METHODS: Solubility studies of Carvedilol in various oils, surfactants and co-surfactants were conducted, followed by the construction of pseudo-ternary phase diagrams and other in vitro assessments. The selected SEDDS formulation (S1) was adsorbed onto solid powder excipients and compressed into tablets. The resulting liquisolid tablets were evaluated under British Pharmacopoeia (B.P.) specifications. Pre- and post-compression studies were performed to determine the flow properties and evaluate the liquisolid systems, followed by in vivo studies in hypertensive rats. RESULTS: Attempts of self-emulsification, droplet size, and thermodynamic stability studies showed acceptable results for the S1 formulation containing Capryol 90, Tween 20, and Transcutol HP (10:53.3:26.2%), respectively. Pre-compression studies showed adequate flowability and compatibility of liquid and solid excipients with Carvedilol. The selected liquisolid tablet (LS7) demonstrated the best disintegration and water absorption ratio in addition to satisfactory friability and hardness. A significantly (p < .05) fast dissolution rate was observed for both SEDDS and liquisolid formulations when compared to pure drug and marketed Carvepress®. The in vivo study of LS7 formulation revealed a rapid significant (p < .01) decrease in the mean arterial pressure (MAP) of the rats (112.72 mmHg) within the first 30 min followed by a further decline (107.22 mmHg) after 1 h when compared to Carvepress®. CONCLUSION: Self-emulsifying liquisolid tablets expressed rapid onset of action with enhanced anti-hypertensive effect of Carvedilol.

Propolis organogel as a novel topical delivery system for treating wounds.

CONTEXT: Propolis has traditionally been used in curing infections and healing wounds and burns. OBJECTIVE: The aim of this study is to formulate pluronic lecithin organogel of propolis to improve its availability and antimicrobial activity. MATERIALS AND METHODS: Different organogels were prepared by using soybean lecithin, isopropyl palmitate, pluronic F127 and water. The effect of quantity of lecithin and pluronic F127 and percentage of oil phase was investigated. The organogels were evaluated for appearance, texture, pH, drug content and viscosity. In vitro release studies were carried out using cellophane membrane. Drug permeation through abdominal rat skin from organogels that showed high % drug release was compared to that from propolis suspension in distilled water. Finally, the antimicrobial activity of the selected propolis formulation against different bacterial isolates was compared with that of propolis suspension in water. RESULTS AND DISCUSSION: Results showed that all organogel formulations except the formula containing 10% pluronic F127, showed acceptable physical properties. Drug content of organogel formulations was in the range of 97.5-100.2%. The pH of the formulations was in the range of 5.5-6.3 that suits the skin pH, indicating skin compatibility. The viscosity was in the range of 5366-8984 cp. A significant decrease in drug release from formulations was observed with increase in concentration of lecithin and pluronic F127. Decreasing oil phase percentage to 20% w/w led to a decrease in drug release from the formulation. CONCLUSION: The formula containing 3% lecithin and 20% pluronic F127 exhibited superior skin permeation and antimicrobial activity over propolis suspension in water.