M. Ghorab

Nanoemulsion as a potential ophthalmic delivery system for dorzolamide hydrochloride.

Dilutable nanoemulsions are potent drug delivery vehicles for ophthalmic use due to their numerous advantages as sustained effect and high ability of drug penetration into the deeper layers of the ocular structure and the aqueous humor. The aim of this article was to formulate the antiglaucoma drug dorzolamide hydrochloride as ocular nanoemulsion of high therapeutic efficacy and prolonged effect. Thirty-six systems consisting of different oils, surfactants, and cosurfactants were prepared and their pseudoternary-phase diagrams were constructed by water titration method. Seventeen dorzolamide hydrochloride nanoemulsions were prepared and evaluated for their physicochemical and drug release properties. These nanoemulsions showed acceptable physicochemical properties and exhibited slow drug release. Draize rabbit eye irritation test and histological examination were carried out for those preparations exhibiting superior properties and revealed that they were nonirritant. Biological evaluation of dorzolamide hydrochloride nanoemulsions on normotensive albino rabbits indicated that these products had higher therapeutic efficacy, faster onset of action, and prolonged effect relative to either drug solution or the market product. Formulation of dorzolamide hydrochloride in a nanoemulsion form offers, thus, a more intensive treatment of glaucoma, a decrease in the number of applications per day, and a better patient compliance compared to conventional eye drops.

Proniosomes as a carrier system for transdermal delivery of tenoxicam

Tenoxicam is a non steroidal anti-inflammatory drug (NSAID) widely used in the treatment of rheumatic diseases and characterized by its good efficacy and less side effects compared to other NSAIDs. Its oral administration is associated with severe side effects in the gastrointestinal tract. Transdermal drug delivery has been recognized as an alternative route to oral delivery. Proniosomes offer a versatile vesicle delivery concept with the potential for drug delivery via the transdermal route. In this study, different proniosomal gel bases were prepared, characterized by light microscopy, revealing vesicular structures, and assessed for their drug entrapment efficiency, stability, their effect on in vitro drug release and ex vivo drug permeation. The lecithin-free proniosomes prepared from Tween 20:cholesterol (9:1) proved to be stable with high entrapment and release efficiencies. The in vivo behaviour of this formula was studied on male rats and compared to that of the oral market product. The investigated tenoxicam loaded proniosomal formula proved to be non-irritant, with significantly higher anti-inflammatory and analgesic effects compared to that of the oral market tenoxicam tablets.

Development of dorzolamide hydrochloride in situ gel nanoemulsion for ocular delivery.

Background: Several in situ gel-forming systems have been developed to prolong the precorneal residence time of a drug and to improve ocular bioavailability. Poloxamer 407 with its thermoreversible gelation and surface active properties was utilized to formulate a novel dorzolamide hydrochloride in situ gel nanoemulsion (NE) delivery system for ocular use. Objective: Improvement of both ocular bioavailability and duration of action for dorzolamide hydrochloride was the aim of this study. Methods: Physicochemical properties, in vitro drug release studies and biological evaluation of the prepared NEs were investigated. Results: The optimum formulation of in situ gel NE consisted of Triacetin (7.80%), Poloxamer 407 (13.65%), Poloxamer 188 (3.41%), Miranol C2M (4.55%), and water (70.59%). Biological evaluation of the designed dorzolamide formulation on normotensive albino rabbits indicated that this formulation had better biological performance, faster onset of action, and prolonged effect relative to either drug solution or the market product. The formula showed a superior pharmacodynamic activity compared to the in situ gel dorzolamide eye drops. This indicated the effectiveness of the in situ gel properties of poloxamer 407, besides formulating the drug in an NE form for improving the therapeutic efficacy of the drug. Conclusion: These results demonstrate the superiority of in situ gel NE to conventional ocular eye drops and in situ gels to enhance ocular drug bioavailability.

Topical liquid crystalline gel containing lornoxicam/cyclodextrin complex

Lornoxicam is a potent analgesic non-steroidal anti-inflammatory drug that can be used topically to relieve pain and to reduce inflammation. The objectives of this study were to improve the therapeutic efficacy of lornoxicam by complexation with cyclodextrins and to formulate it in liquid crystalline gel. Lornoxicam and β-cyclodextrin (βCD) or hydroxypropyl-β-cyclodextrin (HPβCD) complexes were prepared using the kneaded method in 1:1, 1:2, 1:3 and 1:4 drug:CD molar ratios. Inclusion complexation in aqueous solution and solid state was evaluated by the ultraviolet, phase solubility diagram, differential scanning calorimetry, X-ray diffractometry and Fourier-transform infrared spectroscopy. The stoichiometry for the inclusion complex was found to be 1:2 drug:CD molar ratio as determined from Job’s plot. This result was confirmed by the in vitro dissolution studies for the prepared complexes. Among all the prepared complexes, the complex prepared with βCD in 1:2 drug:CD molar ratio showed highest improvement in drug dissolution and was chosen to be formulated in a topical preparation. For developing liquid crystalline gel, different ratios of Brij 97, glycerol and oils (liquid paraffin, isopropyl myristate and Miglyol® 812) were prepared. The formula composed of Brij 97 and glycerol in 3:1 weight ratio, 10% Miglyol® 812 and 40% water showed higher drug release compared to the other prepared gels. Moreover, this formula showed low ex vivo permeation on excised pigskin thus it could offer high topical effect with low systematic side effects. This formula showed superior anti-inflammatory activity when applied topically on rats’ skin after induction of burn compared to that of Feldene® gel.

Rapid pain relief using transdermal film forming polymeric solution of ketorolac

Context: Ketorolac is one of the most potent nonsteroidal anti-inflammatory drugs and is an attractive alternative to opioids for pain management. Objective: Development and evaluation of transdermal ketorolac film forming polymeric solution. Materials and methods: Eudragits® RLPO, RSPO and E100 as well as polyvinyl pyrrolidone K30 dissolved in ethanol were used as film forming solutions. In vitro experiments were conducted to optimize formulation parameters. Different permeation enhancers were monitored for potentiality of enhancing drug permeation across excised pigskin. Results: The use of 10% oleic acid, Lauroglycol® 90 or Azone® with 5% Eudragit® RSPO, showed the highest enhancement effect on ketorolac skin permeation and showed faster analgesic effect compared to the ketorolac tablet. The formula comprising 5% Eudragit® RSPO and 10% Lauroglycol® 90 showed the greatest pharmacodynamic effect and thus was subjected to pharmacokinetic studies. The pharmacodynamic and pharmacokinetic results didn’t run paralleled to each other, as the ketorolac tablets showed higher plasma concentrations compared to the selected ketorolac transdermal formulation. This might be due to the induction of analgesia by the available ethanol in the transdermal preparation. Conclusion: Optimized transdermal ketorolac formulation showed marked ability to ensure fast and augmented analgesic effect that is an essential request in pain management.

Evaluation of the antischistosomal effect of praziquantel in a liposomal delivery system in mice

Abstract Praziquantel liposomes were prepared from different mole fractions of l -α-dipalmitoylphosphatidylcholine and cholesterol according to the thin film method. The liposomes having optimum loading capacity for the drug were evaluated regarding their targeting properties towards the liver in mice. The results revealed pronounced targeting to the liver as well as sustained release properties which reflect its prophylactic action of the encapsulated drug towards Schistosomiasis. This was clearly demonstrated by an increase in the survival rate of mice as well as a statistically significant decrease in the hepatic worm count.

Formulation of Risperidone as Self-Nanoemulsifying Drug Delivery System in Form of Effervescent Tablets

Risperidone is an atypical antipsychotic drug used to treat schizophrenia. This study aims to formulate risperidone as effervescent tablets to improve patient compliance. Different nanoemulsion combinations were loaded with risperidone to improve its poor water solubility then adsorbed on Aeroperl. The formula showing highest drug dissolution was formulated as effervescent tablets. Factorial design was applied for different tablet formulation variables and the prepared formulae were tested for different criteria in comparison with their corresponding formulae containing drug without nanoemulsion formulation. Statistical analysis was used to determine the most desirable tablet formula considering its Carr index, effervescence time, and drug release.

Enhancement of the intranasal delivery of insulin via a novel mucoadhesive Carbopol gel

Objectivesu2002 The objectives of this study were to develop an intranasal insulin gel using Carbopol homogenization rather than neutralization and to examine the effectiveness of the gel compared with a subcutaneous injection.

Host–guest system of etodolac in native and modified β-cyclodextrins: preparation and physicochemical characterization

Etodolac, being a practically insoluble candidate, exhibits certain toxic effects and a limited bioavailability. Upon chronic use, it causes gastro-intestinal injury and increases the risk of ulcer complications. The approach of this study was to improve the physicochemical properties of the drug utilizing complexation phenomenon with β-, methyl-β- and hydroxypropyl-β-cyclodextrins, which may enhance the aqueous solubility and dissolution rate of etodolac, in an effort to increase oral bioavailability. In certain instances, this approach can be used to increase drug solubility, improve organoleptic properties and maximize the gastrointestinal tolerance by reducing drug irritation after oral administration. Differential UV measurements as well as continuous variation plots revealed the formation of equimolar complex with hydroxypropyl-β-cyclodextrin and 1:2 complexes with β-cyclodextrin and its methyl derivative. Differential scanning calorimetry (DSC), X-ray and FT-IR measurements were applied to prove inclusion complex formation and characterize the complexes. These results lend support to the idea that solubilization of etodolac is mainly related to inclusion complex formation and to a lesser extent to cyclodextrin aggregates. Understanding the factors that influence the performance of etodolac, will allow us to state that molecular encapsulation of the drug and other modifications with appropriate hydroxylation or methylation of parent β-cyclodextrin is able to overcome its problems and facilitate safe and efficient delivery of the drug.