Neuroprotective effect of Berberine Nanoparticles Against Seizures in Pentylenetetrazole Induced Kindling Model of Epileptogenesis: Role of Anti-Oxidative, Anti-Inflammatory, and Anti-Apoptotic Mechanisms

There is an unmet need to develop alternative therapeutic strategies to not only restrain seizures but also to alleviate the underlying pathologies and sequelae. Berberine (BBR), an isoquinoline alkaloid, has shown promising effect in the kindling model of epileptogenesis, but due to the poor oral bioavailability its clinical application is limited. So, the present study was designed to study the neuroprotective effect of BBR nanoparticles (enhanced bioavailability as compared to BBR) against seizures in pentylenetetrazole (PTZ) induced kindling model of epileptogenesis. Kindling model was established in male Wistar rats by intraperitoneal (i.p.) administration of PTZ (30 mg/kg) on every alternate day till the animal became fully kindled or till 6 weeks. Three doses of BBR (50, 100, and 200 mg/kg) and nano-BBR (25, 50, 100 mg/kg) were studied for seizure score, percentage of animal kindled, histopathological score, oxidative stress, inflammation, and apoptosis in PTZ treated rats by conducting cytokines, gene expression and protein expression analysis. BBR nanoparticles showed significant effect on the seizure score and percentage of animal kindled, histopathological score, neurobehavioral parameters (Forced swim test, Rotarod), oxidative (MDA, SOD, GSH, GPx) and inflammatory (IL-1beta, TNF-alpha) parameters, apoptotic parameters (Bax and iNOS), and gene (Nrf2, NQO1, HO1) and protein expression (Nrf2) as compared to both PTZ and BBR. BBR nanoparticles showed neuroprotective effect in PTZ induced kindling model of epileptogenesis and proves to be a promising antiepileptogenic therapy for the patients who are at high risk of developing seizures.

Preclinical Investigation of Transdermal Route for Enhanced Bio-performance of Duloxetine HCl

The aim of the study was to develop and optimise drug-in-adhesive (DIA) transdermal patch of duloxetine HCl for enhanced drug delivery. DIA patch so developed reduced the dose and dosing frequency by enhancing bio-performance of the drug. A transdermal DIA patch having Duro-Tak 87-2287 as DIA polymer and Transcutol P as permeation enhancer loaded with 40% drug previously complexed with MeβCD duly characterised (FTIR, DSC, and SEM) was developed for in vivo study. Pharmacokinetic parameters of developed formulation were assessed and compared with oral route of administration. Among various permeation enhancers (PEs), Transcutol P exhibited most enhanced permeation (ER ≈ 1.99) in terms of flux and Q24 compared to control group having. Mean of maximum plasma concentration (Cmax) and area under time-concentration curve (AUC0-72) in Wistar rats (n = 6) for transdermal patch (10 mg/kg) was found to be 70.31 ± 11.2 ng/ml and 2997.29 ± 387.4 ng/ml*h, respectively, and were considerably higher than oral dose of DLX (20 mg/kg and 10 mg/kg). Albeit, T1/2 was higher in case of transdermal delivery, but this was due to sustained behaviour of delivery system. These findings highlight the significance of both inclusion complexation and transdermal delivery of DLX using DIA patch for efficient drug absorption.

Evaluation of Voice After Definitive Radiotherapy in Patients of Early Stage Squamous Cell Carcinoma of Larynx (Glottis): A Prospective Observational Study

Post treatment voice quality is an important consideration in choosing the management option for laryngeal cancer. We assessed voice quality after radiotherapy in patients of early squamous cell carcinoma of glottis comprehensively using Videolaryngostroboscopy (VLS), Grade, Roughness, Breathiness, Asthenia and Strain (GRBAS) scores and Voice Handicap Index (VHI)-10. Fifty four consenting patients of early squamous cell carcinoma of glottis (Tis, T1 and T2) awaiting definitive radiotherapy were recruited consecutively. Voice was evaluated by VLS, GRBAS scores and VHI-10 before radiotherapy as well as 3 months and 12 months after radiotherapy. There were 52 males and 2 females in the study. Hoarseness of voice was the commonest presenting symptom. Mean duration of symptoms was 2.45 months (± 0.80), ranging from 1 to 4 months. 35 (64.82%) were T1 while 19 (35.18%) were T2 lesions. They received 60-70 Gy of radiotherapy in 28-35 fractions. There was only one recurrence on follow up for 12 months. On VLS at 12 months post-RT the periodicity, phase symmetry, mucosal waves and amplitude were normal in 74.07%, 70.37%, 56.67% and 78.7% cases respectively. Complete glottic closure was obtained in 72.22%. The voice was 'acceptable' (Grade 1 or 2 on VLS parameters) in more than 90% cases. Mean total GRBAS score was 3.39 (± 2.67). Mean total VHI-10 was 6.7 (± 1.75). All indices were significantly better than pre RT levels. Good quality of voice can be expected after radiotherapy for early glottic cancer in majority of patients.

Advancements in redox-sensitive micelles as nanotheranostics: A new horizon in cancer management

World Health Organisation (WHO) delineated cancer as one of the foremost reasons for mortality with 10 million deaths in the year 2020. Early diagnosis and effective drug delivery are of utmost importance in cancer management. The entrapment of both bio-imaging dyes and drugs will open novel avenues in the area of tumor theranostics. Elevated levels of reactive oxygen species (ROS) and glutathione (GSH) are the characteristic features of the tumor microenvironment (TME). Researchers have taken advantage of these specific TME features in recent years to develop micelle-based theranostic nanosystems. This review focuses on the advantages of redox-sensitive micelles (RSMs) and supramolecular self-assemblies for tumor theranostics. Key chemical linkers employed for the tumor-specific release of the cargo have been discussed. In vitro characterisation techniques used for the characterization of RSMs have been deliberated. Potential bottlenecks that may present themselves in the bench-to-bedside translation of this technology and the regulatory considerations have been deliberated.

Forging Ahead the Repositioning of Multitargeted Drug Ivermectin

With the advent of ivermectin, tremendous improvement in public health has been observed, especially in the treatment of onchocerciasis and lymphatic filariasis that created chaos mostly in rural, sub-Saharan Africa and Latin American countries. The discovery of ivermectin became a boon to millions of people that had suffered in the pandemic and still hold its pharmacological potential against these. Ivermectin continued to surprise scientists because of its notable role in the treatment of various other tropical diseases (Chagas, leishmaniasis, worm infections, etc.) and is viewed as the safest drug with the least toxic effects. The current review highlights its role in unexplored avenues towards forging ahead of the repositioning of this multitargeted drug in cancer, viral (the evaluation of the efficacy of ivermectin against SARS-Cov-2 is under investigation) and bacterial infection and malaria. This article also provides a glimpse of regulatory considerations of drug repurposing and current formulation strategies. Due to its broad-spectrum activity, multitargeted nature and promising efforts are put towards the repurposing of this drug throughout the field of medicine. This single drug originated from a microbe, changed the face of global health by proving its unmatched success and progressive efforts continue in maintaining its bequestnin the management of global health by decreasing the burden of various diseases worldwide.

Pharmaceutical strategies for the treatment of bacterial biofilms in chronic wounds

Biofilms are sessile communities of microorganisms, mainly bacteria, that grow on biotic and abiotic surfaces. These microorganisms are embedded within an extracellular polymeric substance that provides enhanced protection from antimicrobials. Chronic wounds provide an ideal habitat for biofilm formation. Bacteria can easily attach to wound debris and can infect the wound due to an impaired host immune response. This review highlights the mechanism of biofilm formation and the role of biofilms in the pathophysiology of chronic wounds. Our major focus is on various formulation strategies and delivery systems that are employed to eradicate or disperse biofilms, thereby effectively managing acute and chronic wounds. We also discuss clinical research that has studied or is studying the treatment of biofilm-infected chronic wounds. Teaser: Innovative pharmaceutical strategies such as hydrogels, nanofibers, films and various nanoscale materials can provide promising approaches for the treatment of biofilm-mediated chronic wound infections, offering the potential to improve therapeutic outcomes.

Long Acting Polycaprolactone Based Parenteral Formulation of Aripiprazole Targeting Behavioural and Biochemical Deficit in Schizophrenia

Schizophrenia is a neurodevelopmental disorder which is expressed in the form of disturbed behaviour and abnormal mental functions. Patient's non-adherence to the medicine is the main cause of failure of drug therapy and increases incidence of relapses. Thus, for successful management of disease long acting parenteral formulations were developed. Aripiprazole was encapsulated in biocompatible polycaprolactone microsphere by o/w emulsion solvent-evaporation method in order to achieve sustained release of the drug for several weeks after single subcutaneous administration. They were optimised on the basis of various parameters such as physical appearance, particle size (49.4 μm-387.1 μm), encapsulation efficiency (70%-95%), percentage yield (33%-75%) and drug loading (25.9%-47.5%). The surface topography and sphericity of the microspheres was determined by scanning electron microscopy which revealed that the microspheres formed were spherical and non-porous in nature. The in vitro releases from the selected formulations were found to be 87% and 95% respectively after 45 days of dissolution. In vivo efficacy of optimised formulation showed significantly (p < 0.05) amelioration of various positive, negative and cognitive symptoms associated with schizophrenia and oxidative stress markers in ketamine-induced schizophrenia model in rats for 30 days.

Impact of cyclodextrin derivatives on systemic release of duloxetine HCl via buccal route

Aim: The aim of this work was to develop buccoadhesive tablets for the systemic delivery of duloxetine HCl (DXT) using more soluble derivatives of β-cyclodextrin, i.e. hydroxypropyl-β-cyclodextrin (HPβCD) and sulfobutylether-β-cyclodextrin (SBEβCD) and to investigate enhanced cellular uptake of inclusion complexed drug.Materials and methods: Freeze dried and spray dried complexes of both cyclodextrin derivatives with DXT (1:1 molar) were prepared and characterized with DSC, FTIR, and PXRD techniques. C971 and PC, on the basis of swelling behavior, erosion and in vitro residence time, were selected for further study at different levels (-1, 0, +1) to optimize the formulation in terms of enhanced drug release and ex vivo permeation.Results: SBEβCD based complexes show more aqueous solubility of DXT (0.782 and 0.958 mM) and more complexation efficiency compared to HPβCD at 25 °C and 37 °C, respectively. Apparent stability constant was reported to be higher (1109.94 and 1693.25 M^-1) for DXT-SBEβCD at 25 °C and 37 °C, respectively, than the corresponding values for DXT-HPβCD systems. Enhanced cellular uptake using fibroblast cells was revealed for complexed drug compared to free drug .Conclusion: Both cyclodextrin derivatives are able to enhance drug release and permeation in vitro and ex vivo.

Use of thermal and non thermal techniques for assessing compatibility between mirtazapine and solid lipids

The present investigation was aimed at the evaluation of possible interactions between mirtazapine and selected solid lipids that are commonly used to develop solid lipid nanoparticles (SLNs) and nanostructured lipidic carriers (NLCs). The solids lipids explored were palmitic acid, stearic acid, glycerylmonostearate, cutina CPPH, sterotex NF, gelucire 50/13, hydrogenated castor oil and compritol 888 ATO. The techniques used were Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), Hot Stage Microscopy (HSM) and Isothermal Stress Testing (IST) studies. In some cases, the DSC results indicated the possibility of drug-solid lipid interactions which was further ruled out by performing HSM studies. Moreover, IST studies were also used to further confirm the compatibility between the drug and selected solid lipids. And the findings from these studies indicated compatibility between mirtazapine and solid lipids that can further be used to develop SLNs or NLCs.

Antidepressants as antipruritic agents: A review

Pruritus is a concomitant symptom of various underlying disorders viz. dermatological, systemic and psychiatric disorders that provoke the person to scratch the skin. Many natural as well as, antipruritic therapies are usually practiced in the treatment of pruritus including general preventive measures, topical therapies such as cooling agents, antihistamines, anesthetics, capsaicin, corticosteroids, immunomodulators and; systemic therapies including administration of antihistamines, opioid antagonists/agonists, antiepileptic drugs/neuroleptics (e.g., gabapentin and pregabalin), antidepressants (e.g., doxepin, amitriptyline, paroxetine, fluvoxamine, sertraline, escitalopram and mirtazapine) (Patel and Yosipovitch, 2010; Reich et al., 2011; Martín and Padilla, 2015; Eskeland et al., 2016). Topical therapies are the mainstay of treatment of delicate and localized pruritus while other systemic drug therapies are used to treat stern and generalized pruritus. The reported antipruritic activity of some antidepressant drugs has intrigued this review to focus on the types of pruritus, pruritus mechanism, the antipruritic mechanism of antidepressants and to comprehend the role of antidepressants in the management of pruritus.

Preparation and evaluation of floating tablets of pregabalin

Floating tablets of pregabalin were prepared using different concentrations of the gums (xanthan gum and guar gum), Carbopol 974P NF and HPMC K100. Optimized formulations were studied for physical tests, floating time, swelling behavior, in vitro release studies and stability studies. In vitro drug release was higher for tablet batches containing guar and xanthan gum as compared to the batches containing Carbopol 974P NF. Tablet batches were subjected to stability studies and evaluated by different parameters (drug release, drug content, FTIR and DSC studies). The optimized tablet batch was selected for in vivo pharmacodynamic studies (PTZ induced seizures). The results obtained showed that the onset of jerks and clonus were delayed and extensor phase was abolished with time in treated groups. A significant difference (p > 0.05) was observed in control and treated group behavior indicating an excellent activity of the formulation for a longer period (>12 h).

Modified Release Biodegradable Polymeric Microspheres of Stavudine: Cell Viability, Cellular Uptake, Hemolysis Studies and In Vivo Pharmacokinetics

Family of retroviruses which replicates through the use of the reverse transcriptase enzyme or the enzyme needed to convert RNA to DNA for replication bears Human Immunodeficiency Virus (HIV). It causes irreversible destruction of the immune system leading to the occurrence of opportunistic infections and malignancies. The eradication of HIV is highly unlikely as the cells of the mononuclear phagocyte system (MPS) besides CD4 T lymphocytes are the specific hosts for HIV which need to be targeted even after extended blood plasma profile of antiviral drug to maintain viral suppression and reduced disease progression. Aiming the current goal, biodegradable polymeric microspheres of PLGA 50: 50 (RESOMER(®) 505H) were developed and evaluated. These polymeric particles encapsulating Stavudine (d4T) exhibited nearly 100% cell viability during cytotoxicity studies in comparison to pure d4T. The histological studies have revealed the in vivo biocompatibility while hemolysis studies certified the liability of formulation to be used parenteraly exhibiting no significant hemolytic toxixicty. The in vivo pharmacokinetics has shown the extended drug release from microsphere matrix upto a month. The calculated AUCtotal for d4T loaded polymeric microspheres was found to be 3341.656 μM h/ml; which was nearly 54 times than the total AUC of free d4T injected subcutaneously to the control group of animals; exhibiting the stable d4T concentration in blood avoiding fluctuation of the same indicating decreased probabilities of development of resistance against the treatment. Combination of targeted and subcutaneous administration of d4T will not only provide the stable and extended release of drug but also eradicate the hidden HIV hosted by macrophages. The concomitant regimen will potentially enhance the therapeutic efficacy with patient compliance; renewing new hopes for complete cure and improved quality of life in the AIDS patient.

Critical aspects in rationale design of fluorouracil-based adjuvant therapies for the management of colon cancer

The strategic goal behind adjuvant therapy is to open novel avenues for colon cancer treatment by specifically inactivating pathways needed for the growth of tumor cells. 5-Fluorouracil (5-FU) therapy is a prominent conventional treatment for colon cancer that has been used for five decades. Among the rich diversity of chemotherapeutics, 5-FU has been extensively manipulated as an anticancer drug. The pharmacology of 5-FU has spawned myriad alternatives to achieve low-toxicity treatment for better colon cancer management. The existing highly toxic chemotherapeutic regimens, lack of new congeners with significant efficacy, and drug resistance to cancer cells have prompted scientists to manipulate conventional treatments. These factors make it imperative to rationalize the current 5-FU therapy in combination with synthetic or natural compounds by optimizing the dose with respect to pharmacokinetic and preclinical data. To attempt to tailor effective conventional 5-FU regimens, novel therapeutic perspectives associated with the 5-FU-based colon cancer chemotherapy currently available in clinical settings have been summarized. This review presents comprehensive summary of a dedicated literature search of databases (i.e., PUBMED, CAPLUS, and MEDLINE) for adjuvant approaches such as NSAIDs (COX-II inhibitors), natural compounds, viral vectors, novel agents/molecules, and various targeted therapies, in combination with 5-FU in developing treatment alternatives for colon cancer.

In silico predicative studies for cytotoxic potential of NSAIDs using self-organizing molecular field analysis

Antiproliferative potential of nonsteroidal anti-inflammatory drugs (NSAIDs) has generated an immense interest among the scientific fraternity to assess its broader role in the chemoprevention of colon cancer. Due to serious adverse events associated with the chemotherapy, NSAIDs have been exploited as adjuvants to synergize the cytotoxic potential of conventional chemotherapeutic agents at low-dose regimens. The present investigation has been focused on in silico model generation for in vitro cytotoxicity activity of the clinically active NSAIDs using self-organizing molecular field analysis (SOMFA) studies. A statistically validated robust model for a diverse group of NSAIDs having flexibility in structure and cytotoxicity activity was obtained using SOMFA. The statistical measures having good cross-validated correlation coefficient r (2) (cv) (.8291), noncross-validated correlation coefficient r (2) values (.8686), and high F test value (41.8722) proved significance in the generated model. Analysis of 3-dimensional quantitative structure activity relationship (3D-QSAR) models through electrostatic and shape grids provided additional valuable information regarding shape and electrostatic potential influence on in vitro cytotoxicity profile. The analysis of SOMFA results provided a better insight about the generation of molecular architecture of novel NSAIDs yet to be synthesized, with optimum in vitro cytotoxicity activity and improved therapeutic profile.

A Stability-Indicating RP-HPLC Assay Method for 5-Fluorouracil

The present study describes the development of a validated RP-HPLC method for the determination of 5-fluorouracil in presence of its degradation products or other pharmaceutical excipients. Stress studies were performed on 5-fluorouracil and it was found that it degrades sufficiently in alkaline conditions, while negligible degradation was observed in acidic, neutral, oxidative and photolytic conditions. The peaks of the degradation products were not observed in the chromatogram due to the nonchromophoric nature of the degradation moiety formed. The separations were carried out on a C-18 reversed phase column (Phenomenex; Prodigy ODS3V, 250x4.6 mm, 5 mu) using 50mM KH(2)PO(4) (pH, 5.0) as mobile phase at a flow rate of 1.2 ml/min and temperature of 30 degrees . The wavelength of detection was 254 nm. A retention time of nearly 6 minutes was obtained. Analytical validation parameters such as specificity and selectivity, linearity, accuracy and precision were evaluated. The calibration curve for 5-fluorouracil was linear (r(2)=0.999+/-0.0005) from range of 10 mug/ml to 100 mug/ml. Relative standard deviation values for all the key parameters, was less than 2.0 %. The recovery of the drug after standard addition to the degraded sample was found to be 104.69%. Thus, the developed RP-HPLC method was found to be suitable for the determination of 5-fluorouracil in bulk as well as stability samples of the pharmaceutical dosage forms containing various excipients.

Stress degradation studies on duloxetine hydrochloride and development of an RP-HPLC method for its determination in capsule formulation

Duloxetine hydrochloride (HCl) is an antidepressant drug prescribed for major depressive disorders, pain related to diabetic peripheral neuropathy, and stress urinary incontinence. In the present study, degradation behavior of duloxetine HCl was studied by subjecting the drug to various International Conference on Harmonization-recommended stress conditions. Also, a stability-indicating high-performance liquid chromatography method was established for analysis of the drug in the presence of various degradation products. An acceptable separation of the drug and its degradation products was achieved on a C-8 column at 40 degrees C using a mobile phase comprised of phosphate buffer (pH 2.5)-methanol-tetrahydrofuran in the ratio of 50:40:10 at a flow rate of 1 mL/min. The detection wavelength was 232 nm. The method was validated for linearity, precision, accuracy, selectivity, specificity, and robustness. The method was found to be linear over a concentration range of 1-100 microg/mL (n = 6). The value of slope was found to be 85.735 mV/s ppm with correlation coefficient of 0.9994 and relative standard deviation (RSD) of 0.87%. RSD values ranged from 0.20% to 0.82% in the case of intra-day precision studies, whereas the values ranged from 0.63% to 1.57% in the case of inter-day precision. The drug was found to be stable on exposure of 30% H(2)O(2) for 48 h. It was found to be highly unstable in acidic conditions, as 41.35% degradation was observed in 0.01N HCl at 40 degrees C after 8 h. Degradation was also observed in alkaline and neutral conditions (2.83% and 42.75%, respectively) on refluxing the drug for 1 h. The drug was stable under photolytic and thermal stress on exposure in solid form but showed considerable degradation in solution form.

Development of Pulsatile Systems for Targeted Drug Delivery of Celecoxib for Prophylaxis of Colorectal Cancer

The aim of the present study was to formulate fast release enteric-coated tablets for drug delivery to the colon. Two different approaches were used for the preparation of these tablets. The first included making use of superdisintegrant (SD) in the tablet. The amount of super disintegrant (cross-linked PVP) in the tablet and the coat weight were varied to formulate a suitable time-controlled release system, that would provide colon-specific drug delivery. The second approach consisted of development of osmogen-based tablets for drug delivery into the tracts of the colon. Two different osmogens, sodium chloride and potassium chloride, were used. These also were coated at different coat levels. Celecoxib was used as a model drug. In vitro drug release studies showed that superdisintegrants were more effective in showing burst effect in the tablets and therefore showed a rapid drug release as compared with osmogens, which would show a sustained drug release all through the colon. Osmotic tablets were formulated making use of a high concentration of osmogen sodium chloride (OM-SC) and potassium chloride (OM-KC) were further enteric-coated. These also were found to be useful in providing a sustained delivery of nearly 80-90% of the drug into the colonic region. The coat weight required in these tablets for protection in the upper gastrointestinal conditions varied from 9.69% in OM-KC tablets to 4.65% in OM-SC tablets.

A simple and sensitive stability-indicating RP-HPLC assay method for the determination of aceclofenac

The aim of the present study is to develop a stability-indicating assay method for the determination of aceclofenac after being subjected to different International Conference on Harmonization prescribed stress conditions, such as hydrolysis, oxidation, heat, and photolysis. Aceclofenac (2-[2-[2-(2,6-dichlorophenyl)aminophenyl]acetyl]oxyacetic acid) is decomposed under hydrolytic stress (neutral, acidic, and alkaline) and also on exposure to light (in solution form). The compound is stable to oxidative stress, heat, and photolytic stress (in solid form). The major degradation product is diclofenac, which is confirmed through comparison with the standard. Separation of the drug from major and minor degradation products is achieved on a C-18 column using methanol-0.02% of ortho phosphoric acid in a ratio of 70:30. The method is linear over the concentration range of 17-100 microg/mL (r(2) = 0.9988). The detection wavelength is 275 nm. The method is validated for linearity, range, precision, accuracy, specificity, and selectivity.

Stress Studies on Acyclovir

Acyclovir is an antiviral drug of choice in the treatment of many types of herpes virus infections, including genital herpes simplex infections, herpetic conjunctivitis, herpes simplex encephalitis, etc. The present study describes the degradation behavior of acyclovir under different International Conference on Harmonization recommended stress conditions (hydrolysis, oxidation, photolysis, and thermal decomposition) in order to establish a validated stability-indicating high-performance liquid chromatography method. Acyclovir is found to degrade extensively in acidic conditions and oxidative stress. Mild degradation of the drug occurs in alkaline and neutral conditions. The drug is stable to dry heat. The drug is found to be sufficiently stable after light exposure in a solid state; however, photolytic degradation is observed when the drug is exposed as a solution in water. The major degradation product in acidic hydrolysis and photolysis is identified as guanine through comparison with the standard. Separation of drug and the degradation products under various conditions is successfully achieved on a C-18 column utilizing water-methanol in the ratio of 90:10. The flow rate is 1 mL/min, and the detection wavelength is 252 nm. The method is validated with respect to linearity, precision, accuracy, selectivity, specificity, and robustness. The mean values of slope and correlation coefficient are 39.307 and 0.9998 with relative standard deviation values less than 2%. The recovery of the drug is found to be in the range of 97.34% to 102.35%. From the previous study it is concluded that the stability-indicating method developed for acyclovir can be used for analysis of the drug in various stability samples.

Compression coated systems for colonic delivery of 5-fluorouracil

Compression coating is one of the approaches for delaying the release of drugs. The aim of this study was to develop colon-specific compression coated systems of 5-fluorouracil (5-FU) for the treatment of colorectal cancer using xanthan gum, boswellia gum and hydroxypropyl methylcellulose (HPMC) as the coating materials. Core tablets containing 50 mg of 5-FU were prepared by direct compression. The coating of the core tablets was done using different coat weights (230, 250, 275 and 300 mg) and different ratios (1:2, 2:1, 1:3, 1:7 and 3:4) of boswellia gum and xanthan gum and different ratios (1:1, 1:2, 2:1, and 2:3) of boswellia gum and HPMC. In-vitro release studies were carried out using simulated gastric and intestinal fluids, with and without rat caecal contents. Among the different ratios used for coating with boswellia:xanthan gum combination, ratio 1:3 gave the best release profile with the lowest coating weights of 230 mg (7.47 +/- 1.56% in initial 5 h). Further increase in the coat weights to 250, 275 and 300 mg led to drug release of 5.63 +/- 0.53%, 5.09 +/- 1.56% and 4.57 +/- 0.88%, respectively, in the initial 5 h and 96.90 +/- 0.66%, 85.05 +/- 1.01% and 80.22 +/- 0.35%, respectively, in 24 h. When coating was carried out using different ratios of the combination boswellia gum and HPMC, the ratio 2:3 gave the best results among the initial trial batches (7.80 +/- 0.57% in 5 h). Increasing the coat weights to 250, 275 and 300 mg led to drug release of 6.5 +/- 0.27%, 3.70 +/- 2.3% and 2.99 +/- 0.72%, respectively, in the initial 5 h and 96.90 +/- 0.66%, 85.05 +/- 1.01% and 80.22 +/- 0.35%, respectively, in 24 h. In-vitro studies were further carried out in the presence of 2% w/v rat caecal contents, which led to complete release of the drug from the tablets. Therefore, this study lays a basis for use of compression coating of 5-FU as a tool for delaying the release of the drug, which ensures better clinical management of the disease.

Biodegradable microspheres for parenteral delivery

Nowadays, emphasis is being laid to development of controlled release dosage forms. Interest in this technology has increased steadily over the past few years. Although oral administration of drugs is a widely accepted route of drug delivery, bioavailability of drug often varies as a result of gastrointestinal absorption, degradation by first-pass effect, and hostile environment of gastrointestinal tract. Transdermal administration for percutaneous absorption of drug is limited by the impermeable nature of the stratum corneum. Ocular and nasal delivery is also unfavorable because of degradation by enzymes present in eye tissues and nasal mucosa. Hence, the parenteral route is the most viable approach in such cases. Of the various ways of achieving long-term parenteral drug delivery, biodegradable microspheres are one of the better means of controlling the release of drug over a long time. Because of the lipidic nature of liposomes, problems such as limited physical stability and difficulty of freeze-drying are encountered. Similarly, for emulsions, stability on long-term basis and in suspensions, rheological changes during filling, injecting, and storage poses limitation. Also, in all these systems, the release rate cannot be tailored to the needs of the patient. Parenteral controlled-release formulations based on biodegradable microspheres can overcome these problems and can control the release of drug over a predetermined time span, usually in the order of days to weeks to months. Various FDA-approved controlled-release parenteral formulations based on these biodegradable microspheres are available on the market, including Lupron Depot Nutropin Depot and Zoladex. This review covers various molecules encapsulated in biodegradable microspheres for parenteral delivery.

Complexation of celecoxib with beta-cyclodextrin: characterization of the interaction in solution and in solid state

Inclusion complexation between celecoxib, a specific cyclooxygenase II inhibitor, and beta-cyclodextrin (beta-CD) was studied in solution and solid state. Drug cyclodextrin complexes were prepared by spray drying while physical mixtures were obtained by simple blending. Inclusion complexes were characterized by nuclear magnetic resonance spectroscopy (NMR), differential scanning calorimetry (DSC), X-ray diffractometry (XRD), scanning electron microscopy (SEM), infrared spectroscopy (IR), and polarimetry. Phase solubility analysis was carried out to determine the stability constant. Solubility studies revealed the existence of a 1:1 complex between celecoxib and beta-CD. NMR studies suggested a strong interaction between celecoxib and beta-CD prepared by spray drying. XRD and SEM analysis illustrated that celecoxib existed as an amorphous complexed form in spray-dried complexes. Dissolution studies showed that the celecoxib entrapped in spray-dried complexes dissolved much faster than the uncomplexed drug and physical mixtures. The data obtained suggest that celecoxib forms an inclusion complex with beta-CD in solution and solid state, which was confirmed by various analytical techniques. A shorter t50% of dissolution is found for the formulation prepared by spray drying when compared on a weight basis in a USP II apparatus.

In vivo evaluation of time and site of disintegration of polysaccharide tablet prepared for colon-specific drug delivery

Compression coating has been found to be useful for colonic drug delivery. The aim of the present investigation was to evaluate a formulation with a considerably reduced coat weight and gum concentration for colonic drug delivery in vivo using gamma scintigraphy. In vitro studies have found this formulation to be useful for delivery of 5-fluorouracil to the colon. Rapidly disintegrating core tablets containing (99m)Tc-DTPA were prepared and compression coating with 150 mg of granules containing a mixture of xanthan (XG), guar gum (GG) and starch. The ratios of the two gums XG:GG in the coat was kept 10:20. In vitro dissolution studies on XG:GG::10:20 tablets containing (99m)Tc-DTPA were carried out in simulated upper GIT conditions and also in presence of colonic contents. Cumulative percent release of technetium in the upper GIT conditions and transit time amounted to 4%. The total amount of technetium released in the 24 h of the dissolution study was 53+/-3.23%. Upon introduction of cecal content into the dissolution medium (4%), the release of technetium from the compression-coated tablet increased to 78.34+/-5.34%. Gamma scintigraphy studies carried out in six healthy human volunteers showed that the tablet remained intact during its transit through the upper GIT. The anatomical site of disintegration was found to be the ascending colon/hepatic flexure and the disintegration of the tablet started between 4 and 6 h post-dose in all the volunteers with a further spread of tracer into the ascending, transverse, descending and sigmoidal colon.

Influence of Formulation and Excipient Variables on the Pellet Properties Prepared by Extrusion Spheronization

Four commercial grades of microcrystalline cellulose, Avicel PH 101, Avicel PH 102, Avicel PH 112 and Avicel PH 302 were compared for extrusion spheronization. Model mixes containing Avicel PH 101 with different proportions of fillers like lactose and dicalcium phosphate dihydrate (DCPD) were also compared to observe the influence of these fillers on the pellet properties. The amount of water used for granulation of Avicel/ Avicel mixes was kept constant so as to evaluate and quantitate the influence of these excipients/fillers on the pellet properties. The various pellet properties evaluated included, drug release, size and size distribution, shape, density, friability and flow. Mean pellet diameter did not vary among the Avicel grades. Pellets prepared with different proportions of Avicel PH 101 and lactose were more or less similar in mean diameter. The same phenomena were observed in case of DCPD as well. Plain lactose pellets were the largest in size. Therefore, it can be inferred that the presence of Avicel suppressed the change in pellet size. Circularity was found to be significantly linear function of log of bulk density of Avicel powders. As revealed by the SEM photographs, pellets of Avicel PH 101 were fairly round where as those containing Avicel PH 302 were dumbbell shaped. Formulations containing DCPD showed the highest circularity. Drug release rate varied in all the formulations. Among the Avicel grades, Avicel PH 302 showed the highest drug release rate where as Avicel PH 101 showed the least. Drug release also varied as a function of the type of filler and their proportion in the pellets. For both the fillers, the drug release increased with an increase in their proportion. Less water was required for formulations containing higher amounts of lactose and DCPD. Plain DCPD failed to spheronize, although pellets of plain lactose could be formed at the investigated level of water.

Poly-epsilon-caprolactone microspheres and nanospheres: an overview

Poly-epsilon-caprolactone (PCL) is a biodegradable, biocompatible and semicrystalline polymer having a very low glass transition temperature. Due to its slow degradation, PCL is ideally suitable for long-term delivery extending over a period of more than one year. This has led to its application in the preparation of different delivery systems in the form of microspheres, nanospheres and implants. Various categories of drugs have been encapsulated in PCL for targeted drug delivery and for controlled drug release. Microspheres of PCL either alone or of PCL copolymers have been prepared to obtain the drug release characteristics. This article reviews the advancements made in PCL-based microspheres and nanospheres with special reference to the method of preparation of these and their suitability in developing effective delivery systems.

Polysaccharide matrices for microbially triggered drug delivery to the colon

Matrix tablets were prepared using xanthan gum (XG) and guar gum (GG) in varying proportions, and the suitability of the prepared tablets was evaluated for colon specific drug delivery. Indomethacin was used as a model drug. The ability of the prepared matrices to retard drug release in the upper gastrointestinal tract (GIT) and to undergo enzymatic hydrolysis by the colonic bacteria was evaluated. For this, drug release studies were carried out in the presence of rat cecal content. Further cecal content of rats with induced enzymatic activity were used. To ascertain the role of bacterial flora in carrying out the hydrolysis of the tablet, cecal content of rats treated with antibiotics were used in the dissolution media. Presence of XG in combination with GG in the tablets could retard drug release in the conditions of the upper GIT. However, the presence of GG and starch made these matrices microbially degradable. Guar gum alone as a drug release-retarding excipient in the matrices does not achieve the desired retardation. Presence of XG in the tablets not only retards the initial drug release from the tablets, but due to high swelling, makes them more vulnerable to digestion by the microbial enzymes in the colon.

Radioactive microspheres in therapeutics

Microspheres as a drug delivery system hold great promise in reaching the goal of controlled drug delivery as well as site specific delivery. In the last few decades, scientific and technological advancements have been made in the research and development of radiolabeled microspheres. These are used successfully for the treatment of various cancers and tumors. Since response to chemotherapy and external radiotherapy is not so effective and hazardous too, so an alternative to this is internal radiation therapy. These radiolabeled microspheres are very stable and have a proven efficacy in the field of primary as well as metastatic cancers. Radioactive microspheres can be selectively targeted to various tumors without undue radiation to the nontumorous tissues. The radioactive microspheres are injected to halt tumor growth via the blood supply, thereby enabling surgical removal once the tumor size decreases. This review provides an outlook to various aspects of radioactive microspheres and their role in treatment of various tumors and cancers.

Chitosan microspheres as a potential carrier for drugs

Chitosan is a biodegradable natural polymer with great potential for pharmaceutical applications due to its biocompatibility, high charge density, non-toxicity and mucoadhesion. It has been shown that it not only improves the dissolution of poorly soluble drugs but also exerts a significant effect on fat metabolism in the body. Gel formation can be obtained by interactions of chitosans with low molecular counterions such as polyphosphates, sulphates and crosslinking with glutaraldehyde. This gelling property of chitosan allows a wide range of applications such as coating of pharmaceuticals and food products, gel entrapment of biochemicals, plant embryo, whole cells, microorganism and algae. This review is an insight into the exploitation of the various properties of chitosan to microencapsulate drugs. Various techniques used for preparing chitosan microspheres and evaluation of these microspheres have also been reviewed. This review also includes the factors that affect the entrapment efficiency and release kinetics of drugs from chitosan microspheres.

Colonic drug delivery of 5-fluorouracil: an in vitro evaluation

Compression coating has been found to be useful for colonic drug delivery. The aim of the present investigation was to design a formulation with a considerably reduced coat weight and gum concentration for colonic delivery of 5-fluorouracil for the treatment of colorectal cancer. Rapidly disintegrating core tablets containing 50 mg of 5-fluorouracil were prepared and compression coating with 175 mg of granules containing a mixture of xanthan gum (XG) and guar gum (GG) in varying proportions was done. With this coat weight, a highly retarded drug release was observed. After 24h of dissolution the mean percent drug release from the compression coated XG:GG 20:20, 20:10 and 10:20 tablets were found to be around 18+/-1.23%, 20+/-1.54% and 30+/-1.77%, respectively. So, the coat weight was further reduced to 150 mg. It was observed that reduction of coat weight did not affect the initial drug release rate in simulated upper gastrointestinal tract (GIT) conditions. At the end of 24h of dissolution the amount of drug released increased to 25+/-1.22%, 36.6+/-1.89% and 42.6+/-2.22%, respectively in XG:GG 20:20, 20:10 and 10:20 tablets. Studies of XG:GG (10:20) tablets in presence of colonic contents showed an increased cumulative percent drug release of 67.2+/-5.23% in presence of 2% cecal content and 80.34+/-3.89% in presence of 4% cecal content after 19 h of incubation.

Biodegradable microspheres for protein delivery

In a very short time, since their emergence, the field of controlled delivery of proteins has grown immensely. Because of their relatively large size, they have low transdermal bioavailabilities. Oral bioavailability is generally poor since they are poorly absorbed and easily degraded by proteolytic enzymes in the gastrointestinal tract. Ocular and nasal delivery is also unfavorable due to degradation by enzymes present in eye tissues and nasal mucosa. Thus parenteral delivery is currently most demanding and suitable for delivery of such molecules. In systemic delivery of proteins, biodegradable microspheres as parenteral depot formulation occupy an important place because of several aspects like protection of sensitive proteins from degradation, prolonged or modified release, pulsatile release patterns. The main objective in developing controlled release protein injectables is avoidance of regular invasive doses which in turn provide patient compliance, comfort as well as control over blood levels. This review presents the outstanding contributions in field of biodegradable microspheres as protein delivery systems, their methods of preparation, drug release, stability, interaction with immune system and regulatory considerations.

Diagnostic Microspheres: An Overview

Diagnostic methods have become increasingly complex and frequently involve the use of agents that must meet the same approval criteria as drugs. The search for diagnostic contrast agents has spread from X-ray to other imaging modalities, especially to magnetic resonance imaging (MRI) and ultrasound. A wide variety of methods have been used to develop microencapsulated agents, from liposomal entrapment to use of biodegradable polymers. Various scientific and technological advancements have been made in the research and development of diagnostic microspheres. Diagnostic microspheres can be used to understand the human body functions in both healthy and sick people. For example, they allow the detection of malignancies vs. benign tissue changes. Diagnostic microspheres give useful clinical information for various diseases, are very stable, and have proven efficacy in the quantitative measurement of blood flow to an organ. This review discusses various aspects of diagnostic microspheres, such as the choice of contrast agents and radioactive molecules, and their applications in blood flow measurements and organ imaging.

Microbially triggered drug delivery to the colon

Increasing acceptance of protein- and peptide-based drugs necessitates an investigation into the suitability of various sites for their administration. Colon is being investigated for delivery of such molecules. Colon-specific drug delivery is designed to target drug molecules specifically to this area. Development of site-specific delivery systems may exploit a specific property of the target site for drug activation/release. The gastrointestinal tract is inhabited by over 400 bacterial species, each having a specific niche in the tract. Colon, the distal part of the intestine is inhabited by a large variety of gram negative microflora. This flora produces a vast number of enzymes which are being exploited for formulation of colon-specific drug delivery systems. A number of microbially activated systems for colon-specific drug delivery are being evaluated. These include prodrugs and synthetic or natural polymer-based delivery systems. This article aims at reviewing the various microbially activated drug delivery systems for colon-specific drug delivery with specific reference to the microflora of the various segments of the gastrointestinal tract and their role in targeting drug delivery to the colon.

Binders for colon specific drug delivery: an in vitro evaluation

The aim of the present study was to develop a single unit, site-specific drug formulation allowing targeted drug release in the colon. Tablets were prepared using polysaccharides or synthetic polymer as binders. These included xanthan gum, guar gum, chitosan and Eudragit E. Indomethacin was used as a model drug. The prepared tablets were enteric coated with Eudragit-L 100 to give protection in the stomach. The coated tablets were tested in-vitro for their suitability as colon specific drug delivery systems. The drug release studies were carried out in simulated stomach environment (pH 1.2) for 2 h followed by small intestinal environment at pH 6.8. The dissolution data obtained from tablets demonstrates that the dissolution rate of the tablet is dependent upon the type and concentration of polysaccharide/polymer used as binder. The results demonstrate that enteric coated tablets containing 3% chitosan as a binder, showed only 12.5% drug release in the first 5 h, which is the usual upper gastrointestinal transit time, whereas, tablets prepared using guar gum as binder, were unable to protect drug release under similar conditions. Preparations with xanthan gum as a binder formed time-dependent release formulations. When used in a concentration of 5.92% in the tablets, 28% drug release was observed in the usual upper gastrointestinal tract conditions. It was also found that enteric coated preparation formulated with 8.88% of Eudragit E as binder could be used to carry water insoluble drug molecules to the colon especially in IBD. The above study shows that chitosan could be successfully used as a binder, for colon targeting of water insoluble drugs in preference to guar gum when used in the same concentration. Additionally, formulations developed with chitosan and Eudragit E would be highly site specific since drug release would be at a retarded rate till microbial degradation or polymer solubilization takes place in the colon.

Polysaccharides in colon-specific drug delivery

Natural polysaccharides are now extensively used for the development of solid dosage forms for delivery of drug to the colon. The rationale for the development of a polysaccharide based delivery system for colon is the presence of large amounts of polysaccharidases in the human colon as the colon is inhabited by a large number and variety of bacteria which secrete many enzymes e.g. beta-D-glucosidase, beta-D-galactosidase, amylase, pectinase, xylanase, beta-D-xylosidase, dextranase, etc. Various major approaches utilizing polysaccharides for colon-specific delivery are fermentable coating of the drug core, embedding of the drug in biodegradable matrix, formulation of drug-saccharide conjugate (prodrugs). A large number of polysaccharides have already been studied for their potential as colon-specific drug carrier systems, such as chitosan, pectin, chondroitin sulphate, cyclodextrin, dextrans, guar gum, inulin, amylose and locust bean gum. Recent efforts and approaches exploiting these polysaccharides in colon-specific drug delivery are discussed.

Colonic drug delivery: prodrug approach

The colon is largely being investigated as a site for administration of protein and peptides, which are degraded by digestive enzymes in the upper GIT. Also for local diseases of the colon, drug administration to the site of action can not only reduce the dose to be administered, but also decrease the side effects. One of the approaches used for colon specific drug delivery is the formation of a prodrug which optimizes drug delivery and improves drug efficacy. Many prodrugs have been evaluated for colon drug delivery. These prodrugs are designed to pass intact and unabsorbed from the upper GIT and undergo biotransformation in the colon releasing the active drug molecule. This biotransformation is carried out by a variety of enzymes, mainly of bacterial origin present in the colon (e.g. azoreductase, glucuronidase, glycosidase, dextranase, esterase, nitroreductase, cyclodextranase, etc.). The present review includes varius prodrug approaches investigated for colon drug delivery and their site specificity.

Permeation enhancers for transdermal drug delivery

The transdermal route has been recognized as one of the highly potential routes of systemic drug delivery and provides the advantage of avoidance of the first-pass effect, ease of use and withdrawal (in case of side effects), and better patient compliance. However, the major limitation of this route is the difficulty of permeation of drug through the skin. Studies have been carried out to find safe and suitable permeation enhancers to promote the percutaneous absorption of a number of drugs. The present review includes the classification of permeation enhancers and their mechanism of action; thus, it will help in the selection of a suitable enhancer(s) for improving the transdermal permeation of poorly absorbed drugs.

Novel oral colon-specific drug delivery systems for pharmacotherapy of peptide and nonpeptide drugs

The increasing number of peptide and protein drugs being investigated demands the development of dosage forms which exhibit site-specific release. Delivery of drugs into systemic circulation through colonic absorption represents a novel mode of introducing peptide and protein drug molecules and drugs that are poorly absorbed from the upper gastrointestinal (GI) tract. Oral colon-specific drug delivery systems offer obvious advantages over parenteral administration. Colon targeting is naturally of value for the topical treatment of diseases of the colon such as Crohn's disease, ulcerative colitis and colorectal cancer. Sustained colonic release of drugs can be useful in the treatment of nocturnal asthma, angina and arthritis. Peptides, proteins, oligonucleotides and vaccines are the potential candidates of interest for colon-specific drug delivery. Sulfasalazine, ipsalazide and olsalazine have been developed as colon-specific delivery systems for the treatment of inflammatory bowel disease (IBD). The vast microflora and distinct enzymes present in the colon are being increasingly exploited to release drugs in the colon. Although the large intestine is a potential site for absorption of drugs, some difficulties are involved in the effective local delivery of drugs to the colon bypassing the stomach and small intestine. Furthermore, differential pH conditions and long transit time during the passage of drug formulations from mouth to colon create numerous technical difficulties in the safe delivery of drugs to the colon. However, recent developments in pharmaceutical technology, including coating drugs with pH-sensitive and bacterial degradable polymers, embedding in bacterial degradable matrices and designing into prodrugs, have provided renewed hope to effectively target drugs to the colon. The use of pH changes is analogous to the more common enteric coating and consists of employing a polymer with an appropriate pH solubility profile. The concept of using pH as a trigger to release a drug in the colon is based on the pH conditions that vary continuously down the GI tract. Polysaccharide and azopolymer coating, which is refractory in the stomach and small intestine yet degraded by the colonic bacteria, have been used as carriers for colon-specific targeting. Finally, the availability of optimal preclinical models and clinical methods fueled the rapid development and evaluation of colon-specific drug delivery systems for clinical use. Future studies may hopefully lead to further refinements in the technology of colon-specific drug delivery systems and improve the pharmacotherapy of peptide drugs.

Bioabsorbable polymers for implantable therapeutic systems

For a long time, subcutaneous implantable drug pellets using nondegradable polymers have been used for long-term, continuous drug administration. The procedure requires surgical implantation and removal of the drug-containing devices or polymeric matrices, which has a significant negative impact on the acceptability of the product candidate. In addition, the release profile from such devices is neither constant nor readily controlled in terms of precision of rate of release and duration of action. These facts have led to the research and development of novel, controllable, nonirritating, noncarcinogenic, biocompatible, and bioabsorbable drug delivery systems for overcoming the drawbacks of nondegradable implantable pellets for prolonged continuous release. Biodegradable implantable systems release the drug over a long period of time with simultaneous or subsequent degradation in the tissue of the polymer to harmless constituents, thus avoiding removal once the therapy is complete. This approach has considerably improved patient acceptability and patient compliance. Various bioabsorbable polymers have been evaluated for controlled implantable drug delivery, including hydrogels, copolymers of polylactic and polyglycolic acids, polylactic acid, poly(orthoesters), polyanhydrides, poly(E-caprolactone), and polyurethanes. Their characteristics have been studied using a variety of drugs, like anticancer agents, hormone agonists and antagonists, nonsteroidal anti-inflammatory agents, neuroleptics, contraceptives, and others. The present paper describes the current research on implantable therapeutic systems, the bioabsorbable polymers, and the biologically active agents being used in this approach.

Effects of carp pituitary fractions on vitellogenesis, ovarian maintenance, and ovulation in hypophysectomized catfish, Heteropneustes fossilis (Bloch)

Carp pituitary extracts obtained from the puntius carp, Puntius gonio-notus, the grass carp, Ctenopharyngodon idellus, and the big head carp, Aristichthys nobilis, were subjected to gel filtration on Sephadex G-100. The water-soluble proteins in the pituitary extracts resolved into three distinct components, referred to as fractions I, II and III. They were tested for their gonadotrophic activity in the female catfish, Heteropneustes fossilis, by evaluating ovarian maintenance and ovulation in hypophysectomized gravid specimens during the spawning season (July—August), and the induction of oogenesis and vitellogenesis in the regressed ovaries of hypophysectomized specimens during the preparatory period (February). Daily treatment with the puntius carp pituitary fraction II (100 or 300 μg) reinitiated and restored oogenesis and vitellogenesis. The grass carp pituitary fraction II (300 μg) induced vitellogenesis but its potency was much less than that of the puntius carp pituitary fraction II. The big head carp pituitary fraction II was ineffective. Daily treatment with the puntius carp pituitary fraction II (1 or 5 μg) maintained the yolky oocytes in the gravid ovaries and prevented atresia. Ovulation and spawning were induced in hypophysectomized gravid catfish by a single dose of the puntius carp pituitary fraction II (100 or 150 μg). The first and third fractions from the three species of carps were ineffective. Thus, all the reproductive processes in the hypophysectomized female catfish were initiated and/or maintained solely by the puntius carp pituitary fraction II.