Contribution of GLC3A locus to Primary Congenital Glaucoma in Pakistani population.

OBJECTIVES: To check the contribution of GLC3A locus to primary congenital glaucoma in the Pakistani population. METHODS: We enrolled twenty-nine sporadic cases and three families with multiple individuals affected with recessive primary congenital glaucoma in the year 2013. It was a genetic linkage study accomplished jointly in Department of Biotechnology of Lahore College for Women University and School of Biological Sciences, University of the Punjab, Lahore. Samples from all affected individuals were checked for homozygosity for alleles of microsatellite markers spanning CYP1B1 at GLC3A locus. Genotyping was performed with fluorescently labeled primers by capillary electrophoresis. For familial cases, linkage was evaluated by checking the co-segregation of the phenotype with the genotypes. Two-point LOD score was calculated for each microsatellite marker with MLINK. RESULTS: Our study revealed that GLCA3 may contribute to glaucoma in 17% of the sporadic cases and patients in 2 of the 3 families. CONCLUSIONS: This data suggests that the GLC3A may make an important contribution to autosomal recessive primary congenital glaucoma in the Pakistani population. Genotyping and Sequencing of more families will be helpful to identify the common mutations in CYP1B1 in future.

Microemulsions as a surrogate carrier for dermal drug delivery.

Microemulsions are isotropic, thermodynamically stable transparent (or translucent) systems of oil, water, and surfactant, frequently in combination with a cosurfactant with a droplet size usually in the range of 20-200 nm. Since their discovery, they have attained increasing significance both in basic research and in industry. Due to their distinct advantages such as enhanced drug solubility, thermodynamic stability, facile preparation, and low cost, uses and applications of microemulsions have been numerous. Recently, there is a surge in the exploration of microemulsion for transdermal drug delivery for their ability to incorporate both hydrophilic (5-fluorouracil, apomorphine hydrochloride, diphenhydramine hydrochloride, tetracaine hydrochloride, and methotrexate) and lipophilic drugs (estradiol, finasteride, ketoprofen, meloxicam, felodipine, and triptolide) and enhance their permeation. Very low surface tension in conjunction with enormous increase in the interfacial area due to nanosized droplets of the microemulsion influences the drug permeation across the skin. A large number of oils and surfactants are available, which can be used as components of microemulsion systems for transdermal delivery but their toxicity, irritation potential, and unclear mechanism of action limit their use. Besides surfactants, oils can also act as penetration enhancers (oleic acid, linoleic acid, isopropyl myristate, isopropyl palmitate, etc.). The transdermal drug delivery potential of microemulsions is dependent not only on the applied constituents of the vehicle but also drastically on the composition/internal structure of the phases which may promote or hamper the drug distribution in the vehicles. This article explores microemulsion as transdermal drug delivery vehicles with emphasis on components selection for enhanced drug permeation and skin tolerability of these systems and further future directions.

Nanocarrier for the transdermal delivery of an antiparkinsonian drug.

The purpose of the present study was to investigate the potential of nanoemulsions as nanodrug carrier systems for the percutaneous delivery of ropinirole. Nanoemulsions comprised Capryol 90 as the oil phase, Tween 20 as the surfactant, Carbitol as the cosurfactant, and water as an external phase. The effects of composition of nanoemulsion, including the ratio of surfactant and cosurfactant (Smix) and their concentration on skin permeation, were evaluated. All the prepared nanoemulsions showed a significant increase in permeation parameters such as steady state flux (Jss) and permeability coefficient (Kp) when compared to the control (p<0.01). Nanoemulsion composition (NEL3) comprising ropinirole (0.5% w/w), Capryol 90 (5% w/w), Smix 2:1 (35% w/w), and water (59.5% w/w) showed the highest flux (51.81+/-5.03 microg/cm2/h) and was selected for formulation into nanoemulsion gel. The gel was further optimized with respect to oil concentration (Capryol 90), polymer concentration (Carbopol), and drug content by employing the Box-Behnken design, which statistically evaluated the effects of these components on ropinirole permeation. Oil and polymer concentrations were found to have a negative influence on permeation, while the drug content had a positive effect. Nanoemulsion gel showed a 7.5-fold increase in skin permeation rate when compared to the conventional hydrogel. In conclusion, the results of the present investigation suggested a promising role of nanoemulsions in enhancing the transdermal permeation of ropinirole.

Oil based nanocarrier system for transdermal delivery of ropinirole: a mechanistic, pharmacokinetic and biochemical investigation.

Ropinirole, a recent introduction in the clinical treatment of Parkinson's disease, suffers with the problems of low oral bioavailability and frequent dosing. An effective transdermal nano-emulsion drug delivery system can however resolve these issues effectively with greater therapeutic benefits and clinical significance. Therefore, the present work focuses precisely on pharmacokinetic, biochemical and mechanistic assessment of transdermal nanoemulsion gel in rats induced with Parkinson lesioned brain by 6-OHDA. DSC and FT-IR studies showed that NEG affects the normal lipid packing of stratum corneum to enhance the drug permeation. Study of pharmacokinetic parameters (AUC, C(max), and T(max)) revealed a greater and more extended release of ropinirole from nanoemulsion gel compared to that from a conventional gel (RPG) and oral marketed tablet (Ropitor). The AUC(0→∞) for RPCNG and RPTNG was found to be 928.07 ± 206.5 and 1055.99 ± 251.7 ngh/mL, respectively in comparison to 137.25 ± 31.3 and 467.15 ± 106.1 ngh/mL for RPG and oral tablet, respectively. The relative bioavailability of ropinirole has been enhanced more than two fold by RPTNG. Furthermore, antiparkinson activity was evaluated in terms of estimating the level of thiobarbituric acid reactive substances, glutathione antioxidant enzymes and catalase in lesioned brain of rats. Formulations were also found to be non-toxic and non-irritant by histological investigations.

Niosomes in sustained and targeted drug delivery: some recent advances.

Niosomes represent an emerging class of novel vesicular systems. They are composed of nonionic surfactants which are biodegradable and relatively nontoxic. They were developed as stable and inexpensive alternatives to liposomes. Since their early introduction to cosmetic industry their role has diversified to other application areas. They are now being ardently explored as potential carriers for sustained and targeted drug delivery. In addition to conventional, oral, and parenteral routes, they are amenable to be delivered by ocular, transdermal, vaginal, and inhalation routes. Delivery of biotechnological products including vaccine delivery with niosomes is also an interesting and promising research area. The introduction of provesicular approach in the form of proniosomes has further increased the relevance of these systems. More concerted research efforts, however, are still required to realize the full potential of these novel systems. This review considers the current status and explores the potential of niosomes in drug delivery with special attention to their role in drug targeting. Their methods of preparation, formulation aspects, advantages, limitations, and applications are also discussed.

Enhanced transdermal drug delivery techniques: an extensive review of patents.

Transdermal drug delivery system has been accepted as potential non-invasive route of drug administration, with advantages of avoidance of the first-pass metabolism, sustained therapeutic action and better patient compliance, though, its prevalent use is restricted due to excellent impervious nature of skin. It is the greatest challenge for researchers to surmount the inherent limitations imposed by stratum corneum of skin, for enhanced transdermal drug delivery to achieve systemic therapeutic concentration. Thus, many approaches have been attempted to perturb skin barrier and enhance the transdermal delivery of drug. The major approaches for enhancing transdermal delivery are physical enhancers (ultrasound, iontophoresis, electroporation, magnetophoresis, microneedle), vesicles, particulate systems (liposome, niosome, transfersome, microemulsion, solid lipid nanoparticle) and chemical enhancers (sulphoxides, azones, glycols, alkanols, terpenes etc.). The present review explores recent patents on techniques employed to breach the skin barrier for drug permeation along with their penetration enhancement mechanisms.

CNS drug delivery systems: novel approaches.

The brain is a delicate organ, and nature has very efficiently protected it. The brain is shielded against potentially toxic substances by the presence of two barrier systems: the blood brain barrier (BBB) and the blood cerebrospinal fluid barrier (BCSFB). Unfortunately, the same mechanisms that protect it against intrusive chemicals can also frustrate therapeutic interventions. Despite aggressive research, patients suffering from fatal and/or debilitating central nervous system (CNS) diseases, such as brain tumours, HIV encephalopathy, epilepsy, cerebrovascular diseases and neurodegenerative disorders, far outnumber those dying of all types of systemic cancers or heart diseases. The abysmally low number of potential therapeutics reaching commercial success is primarily due to the complexity of the CNS drug development. The clinical failure of many probable candidates is often, ascribable to poor delivery methods which do not pervade the unyielding BBB. It restricts the passive diffusion of many drugs into the brain and constitutes a significant obstacle in the pharmacological treatment of central nervous system (CNS) disorders. General methods that can enhance drug delivery to the brain are, therefore, of great pharmaceutical interest. Various strategies like non-invasive methods, including drug manipulation encompassing transformation into lipophilic analogues, prodrugs, chemical drug delivery, carrier-mediated drug delivery, receptor/vector mediated drug delivery and intranasal drug delivery, which exploits the olfactory and trigeminal neuronal pathways to deliver drugs to the brain, are widely used. On the other hand the invasive methods which primarily rely on disruption of the BBB integrity by osmotic or biochemical means, or direct intracranial drug delivery by intracerebroventricular, intracerebral or intrathecal administration after creating reversible openings in the head, are recognised. Extensive review pertaining specifically, to the patents relating to drug delivery across the CNS is currently available. However, many patents e.g. US63722506, US2002183683 etc., have been mentioned in a few articles. It is the objective of this article to expansively review drug delivery systems for CNS by discussing the recent patents available.

Feasibility of proniosomes-based transdermal delivery of frusemide: formulation optimization and pharmacotechnical evaluation.

The aim of the present study was to formulate non-ionic surfactant vesicles of frusemide to enhance its skin permeation and to develop a transdermal therapeutic system using provesicular approach. The effect of various formulation variables on the transdermal flux, amount of drug deposited in skin, and plasma level of drug were studied. The skin permeation studies were conducted on rat skin and human skin for quantification of permeation parameters. With PGS3 formulation [Span 40:soyalecithin:cholesterol (4.5:4.5:1)], the plasma level in the rats had reached to a level of 0.42 +/- 0.13 microg/mL at the sampling interval of 4 hr and remained within the therapeutic concentration range (1.66-0.3 microg/mL) for the next 12 hr. Results showed that proniosomal formulation was able to sustain the drug level in the blood and offer a promising means for non-invasive delivery of frusemide.

Microemulsions: a novel approach to enhanced drug delivery.

Microemulsions are isotropic, thermodynamically stable transparent (or translucent) systems of oil, water and surfactant, frequently in combination with a cosurfactant with a droplet size usually in the range of 20-200 nm. They can be classified as oil-in-water (o/w), water-in-oil (w/o) or bicontinuous systems depending on their structure and are characterized by ultra low interfacial tension between oil and water phases. These versatile systems are currently of great technological and scientific interest to the researchers because of their potential to incorporate a wide range of drug molecules (hydrophilic and hydrophobic) due to the presence of both lipophilic and hydrophilic domains. These adaptable delivery systems provide protection against oxidation, enzymatic hydrolysis and improve the solubilization of lipophilic drugs and hence enhance their bioavailability. In addition to oral and intravenous delivery, they are amenable for sustained and targeted delivery through ophthalmic, dental, pulmonary, vaginal and topical routes. Microemulsions are experiencing a very active development as reflected by the numerous publications and patents being granted on these systems. They have been used to improve the oral bioavailability of various poorly soluble drugs including cyclosporine and paclitaxel as professed by Hauer et al., US patent 7235248, and Gao et al., US patent 7115565, respectively. Furthermore, they can be employed for challenging tasks such as carrying chemotherapeutic agents to neoplastic cells and oral delivery of insulin as diligently described by Maranhao, US patent 5578583 and Burnside et al., US patent 5824638 respectively. The recent commercial success of Sandimmune Neoral (Cyclosporine A), Fortovase (Saquinavir), Norvir (Ritonavir), etc. also reflects the tremendous potential of these newer drug therapeutic systems. A critical evaluation of recent patents claiming different approaches to improve the drug delivery is the focus of the current review.

Emerging role of microemulsions in cosmetics.

Microemulsions represent a promising carrier system for cosmetic active ingredients due to their numerous advantages over the existing conventional formulations. They are capable of solubilizing both hydrophilic and lipophilic ingredients with relatively higher encapsulation. There is growing recognition of their potential benefits in the field of cosmetic science in addition to the drug delivery. They are now being widely investigated for preparing personal care products with superior features such as having improved product efficiency, stability or appearance. They are well suited for the preparation of various cosmetic products for use as moisturizing and soothing agents, as sunscreens, as antiperspirants and as body cleansing agents. They are also valuable for use in hair care compositions which ensure a good conditioning of the hair as well as good hair feel and hair gloss. They have also found application in after shave formulations which upon application to the skin provide reduced stinging and irritation and a comforting effect without tackiness. These newer formulations elicit very good cosmetic attributes and high hydration properties with rapid cutaneous penetration which may accentuate their role in topical products. These smart systems are also suitable for perfuming purposes where minimum amount of organic solvents is required, such as for perfuming skin or hair. This article highlights the recent innovations in the field of microemulsion technology as claimed by different patents which can bring unique products with great commercial prospects in a very competitive and lucrative global cosmetic market.