A strategic review on the involvement of receptors, transcription factors and hormones in acne pathogenesis

Acne vulgaris is a very common pilosebaceous inflammatory disease occurring primarily on the face and also rare on the upper arms, trunk, and back, which is caused by Propionibacterium, Staphylococcus, Corynebacterium, and other species. Pathophysiology of acne comprises of irregular keratinocyte proliferation, differentiation, increased sebum output, bacterial antigens and cytokines induced inflammatory response. Treatment of acne requires proper knowledge on the pathophysiology then only the clinician can come out with a proper therapeutic dosage regimen. Understanding the pathophysiology not only includes the mechanism but also involvement of receptors. Thus, this review is framed in such a way that the authors have focused on the disease acne vulgaris, pathophysiology, transcription factors viz. the Forkhead Box O1 (FoxO1) Transcription Factor, hormones like androgens and receptors such as Histamine receptors, Retinoic receptor, Fibroblast growth factor receptors, Toll like receptor, Androgen receptor, Liver X-receptor, Melanocortin receptor, Peroxisome proliferator-activated receptor and epidermal growth factor receptors involvement in the progression of acne vulgaris.

Process, Physicochemical Characterization and In-Vitro Assessment of Albendazole Microcrystals

Purpose: Albendazole is a poorly soluble drug which limits its oral bioavailability. The study was focussed to enhance the solubility by in-situ micronization.

Methods: Albendazole microcrystals were prepared by solvent change method using gum karaya and hupu gum as stabilizing agents and the effect of each stabilizer on the prepared microcrystals were studied. FT-IR, DSC, XRD and SEM analysis were performed as a part of characterization studies. The formulations were evaluated for micromeritics, solubility and drug release. The microcrystals that had shown optimized properties were filled into suitable capsules.

Results: The formulations showed reduction in particle size with uniform size distribution and three folds increase in drug release. The microcrystals had shown more than 100-folds increase in solubility compared to pure drug. Surface energy, enthalpy and crystalline nature of microcrystals were found to be reduced. Microcrystals containing gum karaya had shown more drug release. The filled-in capsules also showed increase in drug release rate. The solubility enhancement of albendazole microcrystals was mainly due to the surface adsorption of the stabilizing agents that led to reduction in surface energy and crystalline nature as substantiated by the DSC and XRD studies. The type of stabilizing agent had significant effect on dissolution rate. High affinity of albendazole with gum karaya led to faster drug release profiles.

Conclusion: The study proved that in-situ micronization is an effective technique to enhance the solubility and dissolution rate of poorly soluble drugs like albendazole.

In vitro characterization studies of self-microemulsified bosentan systems

CONTEXT

Bosentan is a poorly soluble drug and pose challenges in designing of drug delivery systems.

OBJECTIVE

The objective of this study is to enhance the solubility, dissolution and shelf-life of bosentan by formulating it as S-SMEDDS capsules.

MATERIALS AND METHODS

Solubility of bosentan was tested in various liquid vehicles such as oils (rice bran and sunflower), surfactants (span 20 and tween 80) and co-surfactants (PEG 400 and propylene glycol) and microemulsions were developed. Bosentan was incorporated into appropriate microemulsion systems which were previously identified from pseudo ternary phase diagrams. Bosentan-loaded SMEDDS were evaluated for drug content, drug release, zeta potential, and droplet size. The selected liquid SMEDDS were converted into solid SMEDDS by employing adsorption and melt granulation. Solid SMEDDS were characterized for micromeritics and evaluated for drug content, drug release, and shelf-life.

RESULTS

Isotropic systems R5, R13, S5, and S13 with submicron droplet size had exhibited 85.45, 94.12, 81.67, and 96.64% drug release, respectively. Solid SMEDDS of MR13 and AS13 formulations with rapid reconstitution ability, exhibited 84.85 and 86.74% of on par drug release. The formulations were physicochemically intact for 1.02 and 1.56 years.

DISCUSSION

Liquid SMEDDS composed with PEG400 had displayed optimal characters. Solid SMEDDS had high-dissolution profiles than bosentan due to modification in the crystalline structure of drug upon microemulsification.

CONCLUSION

Thus, solid SMEDDS addressed the solubility, dissolution, and stability issues of bosentan and becomes an alternate for clinical convenience.

A perspective overview on lipospheres as lipid carrier systems

Both hydrophilic and lipophilic therapeutics can be delivered successfully into deep and peripheral tissues such as cerebrospinal fluid and central nervous system by encapsulating them with crystalline lipids as lipospheres. The advent of lipospheres was meant to deliver both therapeutic moieties with enhanced efficacy and added stability to reach out intended tissue areas. Although extensive information is available on physicochemical, analytical and biopharmaceutical aspects of lipospheres, there was no specific order pertaining to critical composition and rationale of component selection available for academic and pilot scale processing of lipospheres. With the interest of compiling key points in a typical formulation of lipid lipospheres, this article was intrigued to discuss melt method, co-solvent, microemulsion, super critical fluid, spray drying and spray congealing techniques that were employed to scale up lipospheres. The selection criteria for both the drugs and lipids in liposphere formulations were demonstrated here. The quality assessment with variables like loading capacity and entrapment efficiency was explained. A note on preliminary screening factors to determine the liposphere formation such as liposphere dimensions with morphological scenario was detailed in this article. This article also includes the stability and storage issues with reference to photolysis. The marked differential in enhancing solubility and permeability characteristics of Class II and IV drug candidates by liposphere delivery systems with an evident of in vivo outcomes were emphasized.

In vitro and in vivo assessment of piroxicam incorporated Aloe vera transgel

Background:

The aim of the study was to develop piroxicam-Aloe vera gel (PAG) formulation and make a pharmacodynamic evaluation of the formulation.

Materials and Methods:

The gel was prepared by using carbopol 934 as gelling agent and methyl paraben as a preservative in an Aloe vera gel base. The formulated gel was also evaluated for physicochemical parameters like pH, viscosity, drug content, and in vitro diffusion assessment. Pharmacodynamic activity of the formulation was evaluated in Wistar albino rats. The formulated gel was compared with that of similar marketed gel (commercial piroxicam gel (CPG)) against the same parameters.

Results:

From in vitro studies, an effective drug release from PAG was observed to be 68.17% when compared with that of the CPG (62.71%) at 180 min indicating better drug release from the gel formulated in this study. Percentage inhibition of edema was greater for the preparation of PAG (29.57 mean percent inhibition after 60 min) compared to marketed gel which exhibited 18.3% after 60 min.

Conclusion:

It was concluded from the results that the Aloe vera gel acts as an effective gel base to prepare piroxicam gel with high drug loading capacity and improved anti-inflammatory effect. From the statistical analysis the formulation of PAG showed better release than the CPG at p < 0.05 level of significance.

Anatomical, biochemical and physiological considerations of the colon in design and development of novel drug delivery systems

The colon is composed of four distinct layers such as serosa, muscularis externa, sub mucosa and mucosa. There exists a difference in the anatomy, neural and blood supply and absorption characteristics as the length of the colon is traversed. At birth the mucosal surface of the colon is similar to that of the small intestine but rapid changes occur with the loss of the villi leaving flat mucosa with deep crypts. The existence of receptors like muscarinic M3, cholecystokinin1, Eph, Erb B, estrogen (α, β), gastrin releasing peptide, killer Ig like receptor, lymphocyte-endothelial receptor, notch, pregnane X, substance P and peroxisome proliferator-activated γ receptor can be utilized as a promising approach for targeting. The inner compact firm mucus is impervious to bacteria, making it a defensive barrier for the colossal bacterial load. The mucus thus provides innate immunity to maintain the homeostasis in colon. The physiological properties of the colon such as pH, transit time, luminal pressure of the colon, and the presence of microbial flora localized in the colon are utilized in the drug design. The drug delivery systems exploit enteric coating and biodegradable polymers to reach colon in an intact form by surpassing the barriers in the stomach and small intestine. The presence of azo-reductase, glucuronidase, dextranase, pectinase, glycosidase, polysaccharidase made it feasible to design prodrug and enzyme based drug delivery. Drug designing methodologies in colon specific drug delivery include pH- based systems, enzymedepended systems, timed- release systems and pressure/osmotically release systems.