Abdullah M. Al-Mohizea

Solid dispersions: a strategy for poorly aqueous soluble drugs and technology updates

Introduction: Present article reviews solid dispersion (SD) technologies and other patented inventions in the area of pharmaceutical SDs, which provide stable amorphous SDs. Areas covered: The review briefly compiles different techniques for preparing SDs, their applications, characterization of SDs, types of SDs and also elaborates the carriers used to prepare SDs. The advantages of recently introduced SD technologies such as RightSize™, closed-cycle spray drying (CSD), Lidose® are summarized. Stability-related issues like phase separation, re-crystallization and methods to curb these problems are also discussed. A patented carrier-screening tool for predicting physical stability of SDs on the basis of drug–carrier interaction is explained. Applications of SD technique in controlled drug delivery systems and cosmetics are explored. Review also summarizes the carriers such as Soluplus®, Neusilin®, SolumerTM used to prepare stable amorphous SD. Expert opinion: Binary and ternary SDs are found to be more stable and provide better enhancement of solubility or dissolution of poorly water-soluble drugs. The use of surfactants in the carrier system of SD is a recent trend. Surfactants and polymers provide stability against re-crystallization of SDs, surfactants also improve solubility and dissolution of drug.

Everted gut sac model as a tool in pharmaceutical research: limitations and applications.

Objectives  This review discusses the limitations and applications of the everted gut sac model in studying drug absorption, metabolism, and interaction.

Enhanced anti-inflammatory activity of carbopol loaded meloxicam nanoethosomes gel

The aim of the current investigation is to develop nanoethosomes for transdermal meloxicam delivery. The ethosomes were prepared by varying the variables such as concentrations of phospholipids 90G, ethanol, and sonication time while entrapment efficiency, vesicle size and transdermal flux were the chosen responses. Results indicate that the nanoethosomes of meloxicam provides lesser vesicles size, better entrapment efficiency and improved flux for transdermal delivery as compared to rigid liposomes. The optimized formulation (MCEF-OPT) obtained was further evaluated for an in vivo anti-inflammatory activity in rats. Optimized nanoethosomal formulation with vesicles size of 142.3nm showed 78.25% entrapment efficiency and achieved transdermal flux of 10.42μg/cm(2)/h. Nanoethosomes proved to be significantly superior in terms of, amount of drug permeated into the skin, with an enhancement ratio of 3.77 when compared to rigid liposomes. In vivo pharmacodynamic study of carbopol(®) loaded nanoethosomal gel showed significant higher percent inhibition of rat paw edema compared with oral administration of meloxicam. Our results suggest that nanoethosomes are an efficient carrier for transdermal delivery of meloxicam.

Steroidal pyrazolines evaluated as aromatase and quinone reductase-2 inhibitors for chemoprevention of cancer

The aromatase and quinone reductase-2 inhibition of synthesized heterocyclic pyrazole derivatives fused with steroidal structure for chemoprevention of cancer is reported herein. All compounds were interestingly less toxic than the reference drug (Cyproterone(®)). The aromatase inhibitory activities of these compounds were much more potent than the lead compound resveratrol, which has an IC(50) of 80 μM. In addition, all the compounds displayed potent quinone reductase-2 inhibition. Initially the acute toxicity of the compounds was assayed via the determination of their LD(50). The aromatase and quinone reductase-2 inhibitors resulting from this study have potential value in the treatment and prevention of cancer.

Commercially bioavailable proprietary technologies and their marketed products

In this review, we discuss the methodologies and platform technologies for enhancing the oral bioavailability of poorly soluble drugs. We also highlight the mechanisms of formulation technologies for improving desired physicochemical attributes of active substances. We focus on various commercial technologies, along with marketed products, and identify proprietary technologies protected by patents. We also discuss nonpropriety technologies, such as mesoporous silica, cyclodextrin complexation and solid dispersions. In addition, we highlight the factors affecting drug absorption and/or bioavailability, the methodologies available to prepare bioavailability-enhanced products, stability issues and examples of technology implementation.

Transdermal delivery of calcium channel blockers for hypertension

Introduction: Calcium channel blockers are a very important class of antihypertensive drugs. Most calcium channel blockers (CCBs) exhibiting low oral bioavailability are required to be taken more than once a day due to their short half-lives which result in poor patient compliance. There is an ineluctable requirement for improved drug-delivery devices for CCBs because of the quantum of their utilization and shortcoming associated with their conventional dosage forms. Areas covered: There have been worthwhile research endeavors worldwide to investigate the skin permeation and to develop transdermal formulations of various categories of CCBs. This review explores the investigations on the feasibility and applicability of systemic delivery of various CCBs via skin. Expert opinion: Transdermal delivery of CCBs has been particularly acknowledged as a potential drug-delivery route in the therapy of hypertension. Several overtures have been made to enhance delivery of these drugs via skin barrier. There have been remarkable research endeavors worldwide to investigate the skin permeation and to develop transdermal systems of various CCBs. Persistent advancement in this area holds promise for the long-term success in technologically advanced transdermal dosage forms being commercialized sooner rather than later.

5α-reductase inhibitors, antiviral and anti-tumor activities of some steroidal cyanopyridinone derivatives.

We herein report the 5α-reductase inhibitors, antiviral and anti-tumor activities of some synthesized heterocyclic cyanopyridone and cyanothiopyridone derivatives fused with steroidal structure. Initially the acute toxicity of the compounds was assayed via the determination of their LD(50). All the compounds, except 3b, were interestingly less toxic than the reference drug (Prednisolone(®)). Seventeen heterocyclic derivatives containing a cyanopyridone or cyanothiopyridone rings fused to a steroidal moiety were synthesized and screened for their 5α-reductase inhibitors, antiviral and anti-tumor activities comparable to that of Anastrozole, Bicalutamide, Efavirenz, Capravirine, Ribavirin, Oseltamivir and Amantadine as the reference drugs. Some of the compounds exhibited better 5α-reductase inhibitors, antiviral and anti-tumor activities than the reference drugs. The detailed 5α-reductase inhibitors, antiviral and anti-tumor activities of the synthesized compounds were reported.

Momordica charantia polysaccharides mitigate the progression of STZ induced diabetic nephropathy in rats.

Diabetic nephropathy (DN) has become a primary cause of end-stage kidney disease. Several complex dynamics converge together to accelerate the advancement of DN. The present investigation was postulated to explore the mechanism of reno-protective nature of Momordica Charantia polysaccharides (MCP) by evaluating the anti-hyperglycemic, anti-lipidemic as well as markers for oxidative stress and antioxidant proficiency in streptozotocin (STZ)-induced diabetic rats. The oral administration of MCP showed a significant normalization in the levels of kidney function test in the STZ-induced diabetic rats. The levels of blood urea nitrogen (BUN), urea protein and creatinine increased by 316.58%, 195.14% and 800.97% respectively, in STZ-induced diabetic rats when compared with normal rats. MCP treatment also illustrated a significant improvement in glutathione peroxidase, superoxide dismutase and catalase levels, with a significant decline in MDA in diabetic kidneys. Immunoblots of heme-oxygenase 1 (HO-1) and Nrf2 of MCP treated diabetic rats showed a significant up-regulation of HO-1 and Nrf2 protein. Histological and ultra-structural observations also reveal that MCP efficiently protects the kidneys from hyperglycemia-mediated oxidative damage. These findings illustrate that the reno-protective nature of MCP mitigates the progression of STZ induced DN in rats by suppression of oxidative stress and amelioration of the HO-1/Nrf2 pathway.

New targeted-colon delivery system: in vitro and in vivo evaluation using X-ray imaging

The aim of this study was to formulate a new orally-administered colon delivery system of 5-flurouracil (5-FU) for the treatment of colon cancer. The system was designed to target 5-FU directly to the colon with high potential of much more effective and less toxic colon cancer treatment. The system was prepared by compression coating technique using granulated chitosan. The method was optimized by studying the effect of granulation and thickness of the coat with respect to the in vitro performance in a medium mimicking mouth-to-colon environment. The in vivo selectivity of the system was assessed by X-ray imaging technique using beagle dogs. Results showed that granulation of chitosan were effective in protecting against the known acid solubility of the polymer. Formula (F7) with coat weight of  50 mg/tablet exhibited the best protection profile with <10% of the drug released after 6 h. The resistance of the system to the simulated gastro-intestinal media was reduced as the chitosan coat weight decreases. The performance of the system in a rat caecal contents containing-medium showed that the susceptibility of this system for the enzymatic degradation by colonic enzymes. The X-ray imaging gave rise to the in vivo selectivity of this system for colon targeting by showing the resistivity of the system to the stomach and small intestine environment and the selective disintegration of the system inside the large bowel.

Influence of intestinal efflux pumps on the absorption and transport of furosemide

PURPOSE Furosemide is a commonly used diuretic which is used in the treatment of edema, congestive heart failure, hypertension and renal failure. Its absorption exhibits inter- and intra-subject variability that can be attributed to many factors including the intestinal efflux pumps such as the P-glycoprotein (P-gp). This study was done due to the great disagreement between what is published in the literature regarding the influence of P-gp on furosemide and at the same time due to the importance of this drug in the treatment of different conditions as described above. In addition, an investigation of the effect of two of the commonly used pharmaceutical excipients (hydroxypropyl β-cyclodextrin [HPβCD] and Tween 80) and also a P-gp inhibitor (verapamil hydrochloride) on the intestinal absorption of this drug were also done. METHODS The study utilized the everted intestinal sacs technique to investigate both the effect of the efflux transporter (P-gp) on furosemide absorption and also the effect of the chosen excipients. RESULTS The absorption of furosemide was significantly influenced by the P-gp as confirmed by the everted vis the non-everted sacs together with the verapamil study in which the transport of furosemide was inhibited by verapamil. In addition, Tween 80 was also shown to inhibit the P-gp pump whereas the HPβCD did not significantly influence the efflux of furosemide in this study. CONCLUSIONS P-glycoprotein and some of the used excipients in the formulation play a very important role in the transport of furosemide and other drugs. Thus excipients that affect the activity of P-gp should be avoided when formulating drugs that are substrate for the P-gp or other efflux pumps.