Pragna K. Shelat

Topical delivery of clobetasol propionate loaded microemulsion based gel for effective treatment of vitiligo: Ex vivo permeation and skin irritation studies

The aim of the present investigation was to evaluate microemulsion as a vehicle for dermal drug delivery and to develop microemulsion based gel (MBC) of clobetasol propionate (CP) for the effective treatment of vitiligo. D-Optimal mixture experimental design was adopted to optimize the amount of oil (X(1)), S(mix) (mixture of surfactant and cosurfactant) (X(2)) and water (X(3)) in the microemulsion. The formulations were assessed for globule size (nm) (Y(1)) and solubility of CP in microemulsion (mg/ml) (Y(2)). The microemulsion containing 3% oil, 45% S(mix) and 50% water was selected as the optimized batch (ME). The globule size and solubility of CP in ME were 18.26 nm and 36.42 mg/ml respectively. Transmission electron microscopy showed that ME globules were spherical in shape. Carbopol 934P was used to convert microemulsion containing drug into gel form without affecting its structure. Ex-vivo permeation studies showed that cumulative amount of CP permeated (Q(n)) from ME, MBC and market formulation (MFCP) at 8h after application were 53.6±2.18, 28.43±0.67 and 37.73±0.77 μg cm(-2) respectively. MBC showed greater retention of CP in to skin layers than ME and MFCP. Skin irritation studies showed MBC to be significantly less irritating than MFCP. Photomicrographs and scanning electron micrographs of skin sections treated with MBC showed significant changes in the skin structure, which was attributed to the interaction of microemulsion components with skin resulting in permeation enhancement and retention of CP into skin layers. It was concluded that CP loaded gel could be a promising formulation for effective treatment of vitiligo.

Physicochemical and structural characterization of iron–sucrose formulations: a comparative study

Abstract Intravenous polynuclear iron formulations are vital components in the treatment of iron deficiency anemia associated with chronic kidney disease as well as other diseases associated with gastro-intestinal and cardio-vascular system. Intravenous iron preparations consist of iron–carbohydrate nanoparticles with iron–oxyhydroxide as a core covered by carbohydrate shell. These preparations should be very well characterized in terms of their physicochemical properties and pharmacological profile in order to establish safety and efficacy. The present research work was aimed to physicochemically characterize a new generic iron–sucrose preparation (IS-Claris) and establish its equivalency with the reference product (Venofer®). Various analytical techniques including gel permeation chromatography (GPC), mass spectroscopy (MALDI-TOF), absorption spectroscopy, X-ray diffraction analysis (XRD), nuclear magnetic resonance spectroscopy (proton and 13C NMR), Fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis (TGA) were employed. It was observed that the specifications of IS-Claris obtained through these analyses reflect those of Venofer® and hence the two formulations were considered comparable.

Innovation of novel 'Tab in Tab' system for release modulation of milnacipran HCl: optimization, formulation and in vitro investigations.

The study was aimed toward development of modified release oral drug delivery system for highly water soluble drug, Milnacipran HCl (MH). Novel Tablet in Tablet system (TITs) comprising immediate and extended release dose of MH in different parts was fabricated. The outer shell was composed of admixture of MH, lactose and novel herbal disintegrant obtained from seeds of Lepidium sativum. In the inner core, MH was matrixed with blend of hydrophilic (Benecel®) and hydrophobic (Compritol®) polymers. 32 full factorial design and an artificial neuron network (ANN) were employed for correlating effect of independent variables on dependent variables. The TITs were characterized for pharmacopoeial specifications, in vitro drug release, SEM, drug release kinetics and FTIR study. The release pattern of MH from batch A10 containing 25.17% w/w Benecel® and 8.21% w/w of Compritol® exhibited drug release pattern close proximal to the ideal theoretical profile (t50% = 5.92 h, t75% = 11.9 h, t90% = 18.11 h). The phenomenon of drug release was further explained by concept of percolation and the role of Benecel® and Compritol® in drug release retardation was studied. The normalized error obtained from ANN was less, compared with the multiple regression analysis, and exhibits the higher accuracy in prediction. The results of short-term stability study revealed stable chataracteristics of TITs. SEM study of TITs at different dissolution time points confirmed both diffusion and erosion mechanisms to be operative during drug release from the batch A10. Novel TITs can be a succesful once a day delivery system for highly water soluble drugs.

Topical delivery of clobetasol propionate loaded microemulsion based gel for effective treatment of vitiligo – Part II: Rheological characterization and in vivo assessment through dermatopharmacokinetic and pilot clinical studies

Vitiligo is a non contagious acquired pigmentation disorder with limited treatment possibilities. Clobetasol propionate (CP) is the drug-of-choice for vitiligo which suppresses the immune system by reducing immunoglobulin action and causes the restoration of melanocytes leading to repigmentation of skin. However, despite being effective, its low and variable bioavailability prompt for development of novel carrier that could effectively target CP to site of action without producing undesirable side-effects. Low solubility of CP in subsequent poor in vivo bioavailability was overcome by formulating microemulsion based gel of CP (MBC) which would enhance the percutaneous transport of CP into and across the skin barrier. Comprehensive characterization of MBC was carried out for viscosity, gel strength and rheological behavior. In vitro studies revealed much higher drug release, skin penetration and enhanced skin accumulation as compared to control (Cream of CP). In vitro and in vivo occlusion studies demonstrated similar occlusiveness for MBC and control. MBC exhibited 3.16 times higher stratum corneum CP levels compared to control. Visualization of cutaneous uptake in vivo using laser scanning microscopy confirmed targeting of CP to epidermis and dermis. Dermatopharmacokinetic studies of MBC showed enhanced drug deposition of CP in skin layers. MBC was assessed for in vivo efficacy by single blind randomized pilot clinical study. The efficacy was assessed by vitiligo area scoring index (VASI) method. After completion of trial, repigmentation of vitiligo patches in patients were evaluated and scored. MBC was superior in terms of faster repigmentation and efficacy when compared with control (p value<0.5). Hence, it was concluded that CP loaded MBC possess enhanced skin localization as well as therapeutic activity in vitiligo patients.

QbD based development of proliposome of lopinavir for improved oral bioavailability

&NA; Aim of present work was to apply quality by design (QbD) principles for the development of proliposome of poorly soluble lopinavir (LPV). The patient‐centric quality target product profile (QTPP) was defined and critical quality attributes (CQAs) earmarked. Risk assessment studies were carried out to identify the probable risks affecting the CQAs of the product. On the basis of preliminary study, lipid:drug ratio and amount of carrier were selected as critical material attributes (CMAs) and were optimized by face centered central composite design. Liposome vesicle size, drug entrapment efficiency and % drug release after 60 min were selected as CQAs and mathematical relationship between CQAs and CMAs was derived using multiple linear regression analysis. Optimum composition of CMAs, identified using numerical optimization and desirability function, demonstrated excellent entrapment efficiency (> 90%), drug release characteristics (> 95% in 60 min) and had vesicle size of 659.7 ± 23.1 nm. Solid state characterization studies (Differential Scanning Calorimetry, scanning electron microscopy and X‐ray diffraction) were performed for optimized proliposome, suggested transformation of crystalline to amorphous form. Oral bioavailability study in Wistar rats revealed that LPV proliposome exhibited 2.24 and 1.16 fold higher bioavailability than pure LPV and available commercial formulation of LPV/RTV (lopinavir + ritonavir), respectively. Stability study of the optimized LPV loaded proliposome was performed as per ICH guideline and was found to be stable for period of 6 months. Overall results of the study indicate that the proliposome offers advantages of enhanced oral bioavailability for poorly soluble LPV. Graphical abstract Figure. No caption available.

Statistical modeling, optimization and characterization of solid self-nanoemulsifying drug delivery system of lopinavir using design of experiment

Abstract Objective: Lopinavir (LPV), an antiretroviral protease inhibitor shows poor bioavailability because of poor aqueous solubility and extensive hepatic first-pass metabolism. The aim of the present work was to investigate the potential of the solid self-nanoemulsifying drug delivery system (S-SNEDDS) in improving dissolution rate and oral bioavailability of LPV. Materials and methods: Liquid SNEDDS (L-SNEDDS) of LPV were prepared using Capmul MCM C8, Cremophor RH 40 and propylene glycol and their amounts were optimized by Scheffe’s mixture design. L-SNEDDS formulations were evaluated for different physicochemical and in vitro drug release parameters. S-SNEDDS were prepared by adsorbing L-SNEDDS on Neusilin US2 and characterized for solid-state properties. In vivo bioavailability of S-SNEDDS, marketed Lopinavir + Ritonavir (LPV/RTV) formulation and pure LPV was studied in Wistar rats. Stability study of S-SNEDDS was performed as per ICH guidelines. Results and discussion: Optimized L-SNEDDS obtained by Scheffe design had drug loading 160 ± 1.15 mg, globule size 32.9 ± 1.45 nm and drug release >95% within 15 min. Solid state studies suggested the transformation of the crystalline drug to amorphous drug. The size and zeta potential of globules obtained on dilution S-SNEDDS remained similar to L-SNEEDS. In vivo bioavailability study revealed that S-SNEDDS has 2.97 and 1.54-folds higher bioavailability than pure LPV and LPV/RTV formulation, respectively. The optimized S-SNEDDS was found to be stable and had a shelf life of 2.85 years. Conclusion: The significant increase in drug dissolution and bioavailability by prepared SNEDDS suggest that the developed S-SNEDDS is a useful solid platform for improving oral bioavailability of poorly soluble LPV.

Design and Characterization of Buccoadhesive Liquisolid System of an Antihypertensive Drug

Nifedipine is an antihypertensive BCS class II drug which has poor bioavailability when given orally. The objective of the present study was to increase the bioavailability of nifedipine, by formulation and evaluation of a buccoadhesive liquisolid system using magnesium aluminium silicate (Neusilin) as both carrier and coating material and dissolution media were selected based on the solubility studies. A mixture of carboxymethylcellulose sodium and carbomer was used as mucoadhesive polymers. Buccoadhesive tablets were prepared by direct compression. FTIR studies confirmed no interaction between drug and excipients. XRD studies indicated change/reduction in crystallinity of drug. The powder characteristics were evaluated by different flow parameters to comply with pharmacopoeial specifications. The dissolution studies for liquisolid compacts and tablet formulations were carried out and it was found that nifedipine liquisolid tablets formulated from bioadhesive polymers containing 49% liquisolid system, 17.5% carbomer, and 7.5% carboxymethylcellulose sodium showed the best results in terms of dissolution properties. Prepared formulation batches were evaluated for swelling, bioadhesion strength, ex vivo residence time, and permeability studies. The optimized batch was showing promising features of the system. Formulating nifedipine as a buccoadhesive tablet allows reduction in dose and offers better control over the plasma levels.

Chronomodulated drug delivery system of urapidil for the treatment of hypertension

Introduction: Hypertension is a disease which shows circadian rhythm in the pattern of two peaks, one in the evening at about 7pm and other in the early morning between 4 am to 8 am. Conventional therapies are incapable to target those time points when actually the symptoms get worsened. To achieve drug release at two time points, chronomodulated delivery system may offer greater benefits. Materials and methods: The chronomodulated system comprised of dual approach; immediate release granules (IRG) and pulsatile release mini-tablets (PRM) filled in the hard gelatin capsule. The mini-tablets were coated using Eudragit S-100 which provided the lag time. To achieve the desired release, various parameters like coating duration and coat thickness were studied. The immediate release granules were evaluated for micromeritical properties and drug release, while mini-tablets were evaluated for various parameters such as hardness, thickness, friability, weight variation, drug content, and disintegration time and in-vitro drug release. Compatibility of drug-excipient was checked by fourier transform infrared spectroscopy and Differential scanning calorimetry studies and pellets morphology was done by Scanning electron microscopy studies. Results: The in-vitro release profile suggested that immediate release granules gives drug release within 20 min at the time of evening attack while the programmed pulsatile release was achieved from coated mini-tablets after a lag time of 9hrs, which was consistent with the demand of drug during early morning hour attack. Pellets found to be spherical in shape with smooth surface. Moreover compatibility studies illustrated no deleterious reaction between drug and polymers used in the study. Conclusions: The dual approach of developed chronomodulated formulation found to be satisfactory in the treatment of hypertension.

QUANTITATIVE DETERMINATION OF MILNACIPRAN HCL IN RABBIT PLASMA BY HPLC AND ITS APPLICATION TO PHARMACOKINETICS STUDY

A simple, sensitive, and specific reverse phase high performance liquid chromatography (RP-HPLC) method was developed and validated for the quantification of Milnacipran HCl in rabbit plasma. Milnacipran HCl and internal standard (IS, Venlafaxine HCl) were extracted by protein precipitation method with chloroform. The separation was performed on a HiQ sil C18 column (250 mm × 4.6 mm i.d., 5 µm). The wavelength was set at 220 nm. The mobile phase was a mixture of potassium dihydrogen phosphate buffer (0.0125 M) and acetonitrile (72:28%, v/v) with 0.20% triethylamine at a flow rate of 1.0 mL/min. The pH of the solution was adjusted to 3.65 with 0.1 M orthophosphoric acid. The calibration curve was linear over the concentration range 0.1–25 µg/mL. The intra-day and inter-day precision was ranged from 3.9 to 7.3% and 5.2 to 10.8%, respectively. Finally, this proposed method was successfully applied to rabbit pharmacokinetics study and yielded the most comprehensive data on systemic exposure of Milnacipran HCl to date.

In vivo performance evaluation and establishment of IVIVC for osmotic pump based extended release formulation of milnacipran HCl

The objective of the present study was to carry out a pharmacokinetics evaluation of an oral modified release formulation [Aquarius EKX 19102 SRX–2 based osmotic pump (OP)] containing highly soluble milnacipran HCl (MH) as a model drug. It was also aimed at developing an in vitro–in vivo correlation (IVIVC) model for a developed OP. In vivo plasma concentration data were obtained from six healthy male New Zealand albino rabbits after administration of immediate‐release milnacipran HCl solution (IRMHSOL) and milnacipran HCl osmotic pump (MHOP). In vitro samples were analysed using an in house developed spectrophotometry method and in vivo samples were analysed using a RP‐HPLC method developed by the author. A deconvolution based Level A model was attempted through a correlation of the percent in vivo input obtained through deconvolution and the percent in vitro dissolution obtained experimentally. A good correlation between the percentages dissolved vs absorbed (R2 = 0.978) was obtained using level A correlation. Evaluation of the internal predictability of level A correlation was calculated in terms of the percent prediction error, which was found to be below 15%. In a nutshell, the success of the present study warrants further studies in patient volunteers to assess the ability of the MHOP to provide an effective therapy for depression. Copyright