Shahzeb Khan

Exploring recent developments to improve antioxidant, anti-inflammatory and antimicrobial efficacy of curcumin: A review of new trends and future perspectives

Curcumin derivatives have been well-documented due to their natural antioxidant, antimicrobial and anti-inflammatory activities. Curcuminoids have also gained widespread recognition due to their wide range of other activities which include anti-infective, anti-mutagenic, anticancer, anti-coagulant, antiarthrititc, and wound healing potential. Despite of having a wide range of activities, the inherent physicochemical characteristics (poor water solubility, low bioavailability, chemical instability, photodegradation, rapid metabolism and short half-life) of curcumin derivatives limit their pharmaceutical significance. Aiming to overcome these pharmaceutical issues and improving therapeutic efficacy of curcuminoids, newer strategies have been attempted in recent years. These advanced techniques include polymeric nanoparticles, nanocomposite hydrogels, nanovesicles, nanofibers, nanohybrid scaffolds, nanoconjugates, nanostructured lipid carriers (NLCs), nanoemulsion, polymeric micelles and polymeric blend films. Incorporation of curcumin in these delivery systems has shown improved solubility, transmembrane permeability, long-term stability, improved bioavailability, longer plasma half-life, target-specific delivery, and upgraded therapeutic efficacy. In this review, a range of in vitro and in vivo studies have been critically discussed to explore the pharmaceutical significance and therapeutic viability of the advanced delivery systems to improve antioxidant, anti-inflammatory and antimicrobial efficacies of curcumin and its derivatives.

Nanoencapsulation, an efficient and promising approach to maximize wound healing efficacy of curcumin: A review of new trends and state-of-the-art

Wound healing is a multifarious and vibrant process of replacing devitalized and damaged cellular structures, leading to restoration of the skins barrier function, re-establishment of tissue integrity, and maintenance of the internal homeostasis. Curcumin (CUR) and its analogs have gained widespread recognition due to their remarkable anti-inflammatory, anti-infective, anticancer, immunomodulatory, antioxidant, and wound healing activities. However, their pharmaceutical significance is limited due to inherent hydrophobic nature, poor water solubility, low bioavailability, chemical instability, rapid metabolism and short half-life. Owing to their pharmaceutical limitations, newer strategies have been attempted in recent years aiming to mitigate problems related to the effective delivery of curcumanoids and to improve their wound healing potential. These advanced strategies include nanovesicles, polymeric micelles, conventional liposomes and hyalurosomes, nanocomposite hydrogels, electrospun nanofibers, nanohybrid scaffolds, nanoconjugates, nanostructured lipid carriers (NLCs), nanoemulsion, nanodispersion, and polymeric nanoparticles (NPs). The superior wound healing activities achieved after nanoencapsulation of the CUR are attributed to its target-specific delivery, longer retention at the target site, avoiding premature degradation of the encapsulated cargo and the therapeutic superiority of the advanced delivery systems over the conventional delivery. We have critically reviewed the literature and summarize the convincing evidence which explore the pharmaceutical significance and therapeutic feasibility of the advanced delivery systems in improving wound healing activities of the CUR and its analogs.

Secondary Crystal Nucleation: Nuclei Breeding Factory Uncovered

Secondary nucleation, wherein crystal seeds are used to induce crystallization, is widely employed in industrial crystallizations. Despite its significance, our understanding of the process, particularly at the molecular level, remains rudimentary. An outstanding question is why do a few seeds give rise to a many-fold increase in new crystals? Using molecular simulation coupled with experiments we have uncovered the molecular processes that give rise to this autocatalytic behavior. The simulations reveal formation of molecular aggregates in solution, which on coming in contact with the surface of the seed undergo nucleation to form new crystallites. These crystallites are weakly bound to the crystal surface and can be readily sheared by fluid, making the seed surfaces available again to repeat the process. Further, the new crystallites on development can in turn serve as seeds. This mechanistic insight will enable better control in engineering crystalline products to design.

Drug nanocarrier, the future of atopic diseases: Advanced drug delivery systems and smart management of disease

Atopic dermatitis (AD) is a chronically relapsing skin inflammatory disorder characterized by perivascular infiltration of immunoglobulin-E (IgE), T-lymphocytes and mast cells. The key pathophysiological factors causing this disease are immunological disorders and the compromised epidermal barrier integrity. Pruritus, intense itching, psychological stress, deprived physical and mental performance and sleep disturbance are the hallmark features of this dermatological complication. Preventive interventions which include educational programs, avoidance of allergens, exclusive care towards skin, and the rational selection of therapeutic regimen play key roles in the treatment of dermatosis. In last two decades, it is evident from a plethora of studies that scientific focus is being driven from conventional therapies to the advanced nanocarrier-based regimen for an effective management of AD. These nanocarriers which include polymeric nanoparticles (NPs), hydrogel NPs, liposomes, ethosomes, solid lipid nanoparticles (SLNs) and nanoemulsion, provide efficient roles for the target specific delivery of the therapeutic payload. The success of these targeted therapies is due to their pharmaceutical versatility, longer retention time at the target site, avoiding off-target effects and preventing premature degradation of the incorporated drugs. The present review was therefore aimed to summarise convincing evidence for the therapeutic superiority of advanced nanocarrier-mediated strategies over the conventional therapies used in the treatment of AD.

Aceclofenac nanocrystals with enhanced in vitro, in vivo performance: formulation optimization, characterization, analgesic and acute toxicity studies

This study was aimed to enhance the dissolution rate, oral bioavailability and analgesic potential of the aceclofenac (AC) in the form of nanosuspension using cost-effective simple precipitation–ultrasonication approach. The nanocrystals were produced using the optimum conditions investigated for AC. The minimum particle size (PS) and polydispersity index was found to be 112±2.01 nm and 0.165, respectively, using hydroxypropyl methylcellulose (1%, w/w), polyvinylpyrrolidone K30 (1%, w/w) and sodium lauryl sulfate (0.12%, w/w). The characterization of AC was performed using zeta sizer, scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction and differential scanning calorimetry. The saturation solubility of the AC nanocrystals was substantially increased 2.6- and 4.5-fold compared to its unprocessed active pharmaceutical ingredient in stabilizer solution and unprocessed drug. Similarly, the dissolution rate of the AC nanocrystals was substantially enhanced compared to its other counterpart. The results showed that >88% of AC nanocrystals were dissolved in first 10 min compared to unprocessed AC (8.38%), microsuspension (66.65%) and its marketed tablets (17.65%). The in vivo studies of the produced stabilized nanosuspension demonstrated that the Cmax were 4.98- and 2.80-fold while area under curve from time of administration to 24 h (AUC0→24 h) were found 3.88- and 2.10-fold greater when compared with unprocessed drug and its marketed formulation, respectively. The improved antinociceptive activity of AC nanocrystals was shown at much lower doses as compared to unprocessed drug, which is purely because of nanonization which may be attributed to improved solubility and dissolution rate of AC, ultimately resulting in its faster rate of absorption.

Phytotherapeutic potential of natural herbal medicines for the treatment of mild-to-severe atopic dermatitis: A review of human clinical studies

For many decades, natural herbal medicines, polyherbal formulations and/or decoctions of plant-derived materials have widely been accepted as alternative complementary therapies for the treatment, cure or prevention of a wide range of acute and chronic skin diseases including chronic herpes, prurigo, acute and chronic wounds, psoriasis and atopic dermatitis (AD). This review was aimed to summarize and critically discuss about the therapeutic viability and clinical applicability of natural herbal medicines for the treatment of AD in human. The critical analysis of the literature revealed that oral (in the form of capsules, syrup or granules) and/or topical application (alone or in conjunction with wet-wrap dressing and/or acupuncture) of natural herbal medicines exhibit remarkable potential for the treatment of mild-to-severe AD in adults, children, infants and in the pregnant women. In this review, the clinical efficacy of various herbal formulations such as Chinese herbal therapies, Korean medicines, Iranian medicines, honey, natural herbal oils (coconut oil, olive oil and mineral oil), beeswax, dodder seeds and whey for the treatment of AD has been discussed. The clinical anti-AD efficacy of these complementary therapies has been observed in terms of down-regulation in Scoring Atopic Dermatitis (SCORAD) index, erythematic intensity, Childrens Dermatology Life Quality Index (CDLQI), Dermatology Life Quality Index (DLQI), pruritus and itching frequency, transepidermal water loss (TEWL) and expression of AD-mediated chemokines. Conclusively, we recognized that natural herbal medicines demonstrate remarkable clinical efficacy when used alone or in conjunction with other complementary therapies for the treatment of AD in patients of all ages as well as pregnant women.

Fabrication, characterization and in vitro evaluation of silibinin nanoparticles: an attempt to enhance its oral bioavailability

Background Silibinin has gained in importance in the past few decades as a hepatoprotector and is used widely as oral therapy for toxic liver damage, liver cirrhosis, and chronic inflammatory liver diseases, as well as for the treatment of different types of cancers. Unfortunately, it has low aqueous solubility and inadequate dissolution, which results in low oral bioavailability. Materials and methods In this study, nanoparticles (NPs) of silibinin, which is a hydrophobic drug, were manufactured using two cost-effective methods. Antisolvent precipitation with a syringe pump (APSP) and evaporative precipitation of nanosuspension (EPN) were used. The prepared NPs were characterized using different analytical techniques such as scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and X-ray powder diffractometry (XRD) and were sifted for their bioavailability through in vitro dissolution and solubility studies. Moreover, the prepared NPs were evaluated for antimicrobial activity against a battery of bacteria and yeast. Results DSC and XRD studies indicated that the prepared NPs were amorphous in nature, with more solubility and dissolution compared to the crystalline form of this drug. NPs prepared through the EPN method had better results than those prepared using the APSP method. Antimicrobial activities of the NPs were improved compared to the unprocessed drugs, while having comparable activities to standard antimicrobial drugs. Conclusion Results indicate that the NPs have significantly increased solubility, dissolution rate, and antimicrobial activities due to the conversion of crystalline structure into amorphous form.

Smart nanocrystals of artemether: fabrication, characterization, and comparative in vitro and in vivo antimalarial evaluation

Artemether (ARTM) is a very effective antimalarial drug with poor solubility and consequently low bioavailability. Smart nanocrystals of ARTM with particle size of 161±1.5 nm and polydispersity index of 0.172±0.01 were produced in <1 hour using a wet milling technology, Dena® DM-100. The crystallinity of the processed ARTM was confirmed using differential scanning calorimetry and powder X-ray diffraction. The saturation solubility of the ARTM nanocrystals was substantially increased to 900 µg/mL compared to the raw ARTM in water (145.0±2.3 µg/mL) and stabilizer solution (300.0±2.0 µg/mL). The physical stability studies conducted for 90 days demonstrated that nanocrystals stored at 2°C–8°C and 25°C were very stable compared to the samples stored at 40°C. The nanocrystals were also shown to be stable when processed at acidic pH (2.0). The solubility and dissolution rate of ARTM nanocrystals were significantly increased (P<0.05) compared to those of its bulk powder form. The results of in vitro studies showed significant antimalarial effect (P<0.05) against Plasmodium falciparum and Plasmodium vivax. The IC50 (median lethal oral dose) value of ARTM nanocrystals was 28- and 54-fold lower than the IC50 value of unprocessed drug and 13- and 21-fold lower than the IC50 value of the marketed tablets, respectively. In addition, ARTM nanocrystals at the same dose (2 mg/kg) showed significantly (P<0.05) higher reduction in percent parasitemia (89%) against P. vivax compared to the unprocessed (27%), marketed tablets (45%), and microsuspension (60%). The acute toxicity study demonstrated that the LD50 value of ARTM nanocrystals is between 1,500 mg/kg and 2,000 mg/kg when given orally. This study demonstrated that the wet milling technology (Dena® DM-100) can produce smart nanocrystals of ARTM with enhanced antimalarial activities.

Natural and synthetic polymer-based smart biomaterials for management of ulcerative colitis: a review of recent developments and future prospects

Ulcerative colitis (UC) is an inflammatory disease of the colon that severely affects the quality of life of patients and usually responds well to anti-inflammatory agents for symptomatic relief; however, many patients need colectomy, a surgical procedure to remove whole or part of the colon. Though various types of pharmacological agents have been employed for the management of UC, the lack of effectiveness is usually predisposed to various reasons including lack of target-specific delivery of drugs and insufficient drug accumulation at the target site. To overcome these glitches, many researchers have designed and characterized various types of versatile polymeric biomaterials to achieve target-specific delivery of drugs via oral route to optimize their targeting efficiency to the colon, to improve drug accumulation at the target site, as well as to ameliorate off-target effects of chemotherapy. Therefore, the aim of this review was to summarize and critically discuss the pharmaceutical significance and therapeutic feasibility of a wide range of natural and synthetic biomaterials for efficient drug targeting to colon and rationalized treatment of UC. Among various types of biomaterials, natural and synthetic polymer-based hydrogels have shown promising targeting potential due to their innate pH responsiveness, sustained and controlled release characteristics, and microbial degradation in the colon to release the encapsulated drug moieties. These characteristic features make natural and synthetic polymer-based hydrogels superior to conventional pharmacological strategies for the management of UC.

Nanomedicines as emerging platform for simultaneous delivery of cancer therapeutics: new developments in overcoming drug resistance and optimizing anticancer efficacy

Abstract Development and formulation of an efficient and safe therapeutic regimen for cancer theranostics are dynamically challenging. The use of mono-therapeutic cancer regimen is generally restricted to optimal clinical applications, on account of drug resistance and cancer heterogeneity. Combinatorial treatments can employ multi-therapeutics for synergistic anticancer efficacy whilst reducing the potency of individual moieties and diminishing the incidence of associated adverse effects. The combo-delivery of nanotherapeutics can optimize anti-tumor efficacy while reversing the incidence of drug resistance, aiming to homogenize pharmacological profile of drugs, enhance circulatory time, permit targeted drug accumulation, achieve multi-target dynamic approach, optimize target-specific drug binding and ensure sustained drug release at the target site. Numerous nanomedicines/nanotherapeutics have been developed by having dynamic physicochemical, pharmaceutical and pharmacological implications. These innovative delivery approaches have displayed specialized treatment effects, alone or in combination with conventional anticancer approaches (photodynamic therapy, radiotherapy and gene therapy), while reversing drug resistance and potential off-target effects. The current review presents a comprehensive overview of nanocarrier aided multi-drug therapies alongside recent advancements, future prospects, and the pivotal requirements for interdisciplinary research.