DDSolver: an add-in program for modeling and comparison of drug dissolution profiles

Development of dual toxoid-loaded layersomes for complete immunostimulatory response following peroral administration

AIM

Present study reports the development of divalent vaccine with enhanced protection, permeation and presentation following peroral immunization.

MATERIALS & METHODS

Layersomes were prepared by layer-by-layer tuning of polyelectrolytes on liposomes template. The developed system was evaluated for in vitro stability of antigen and layersomes, cell-based assays and immunization experiments in mice.

RESULTS

Layersomes exhibited enhanced stability in simulated biological fluids, still preserving the integrity, biological activity and conformational stability of toxoids. Layersomes also exhibited complete and protective (>0.1 IU/ml) immunostimulatory response include serum IgG titer, mucosal sIgA titer and cytokines (IL-2 and IFN-γ) levels following peroral administration.

CONCLUSION

The positive findings of proposed strategy are expected to contribute significantly in the field of stable liposomes technology and peroral immunization.

Design, Development and Optimization of S (-) Atenolol Floating Sustained Release Matrix Tablets Using Surface Response Methodology

The objective of this present investigation was to develop and formulate floating sustained release matrix tablets of s (-) atenolol, by using different polymer combinations and filler, to optimize by using surface response methodology for different drug release variables and to evaluate the drug release pattern of the optimized product. Floating sustained release matrix tablets of various combinations were prepared with cellulose-based polymers: Hydroxypropyl methylcellulose, sodium bicarbonate as a gas generating agent, polyvinyl pyrrolidone as a binder and lactose monohydrate as filler. The 3² full factorial design was employed to investigate the effect of formulation variables on different properties of tablets applicable to floating lag time, buoyancy time, % drug release in 1 and 6 h (D_{1 h,}D_{6 h}) and time required to 90% drug release (t_90%). Significance of result was analyzed using analysis of non variance and P < 0.05 was considered statistically significant. S (-) atenolol floating sustained release matrix tablets followed the Higuchi drug release kinetics that indicates the release of drug follows anomalous (non-Fickian) diffusion mechanism. The developed floating sustained release matrix tablet of improved efficacy can perform therapeutically better than a conventional tablet.

Dissolution of Intact, Divided and Crushed Circadin Tablets: Prolonged vs. Immediate Release of Melatonin

Circadin 2 mg prolonged-release tablet is the only licensed melatonin product available in the UK. Circadin is indicated for patients with primary insomnia aged 55 and over, but is more widely used "off-label" to treat sleep disorders especially in the paediatric population. Children and older people often have difficulty swallowing tablets and dividing the tablet is sometimes required to ease administration. The aim of this study was to measure the release profile of melatonin from Circadin tablets when divided or crushed, and compare this with release from intact tablets. Dissolution testing was also performed for unlicensed melatonin products for comparison. Dissolution tests were performed using the pharmacopoeial paddle apparatus, with melatonin release analyzed by high performance liquid chromatography. Melatonin content, hardness, friability, and disintegration of the products were also evaluated. The prolonged release of melatonin from Circadin tablets was unlike that of any other product tested. When divided into halves, Circadin preserved most of the prolonged-release characteristic (f2 = 58), whereas quarter-cut and crushed tablet had a more immediate melatonin release profile. Circadin is significantly less expensive and should be preferred to unlicensed medicines which are not pharmaceutically equivalent and offer less quality assurance.

Disease specific modeling: Simulation of the pharmacokinetics of meloxicam and ibuprofen in disease state vs. healthy conditions

PURPOSE

Studies have shown altered pharmacokinetic patterns (PK) in patient suffering from acute pain. Thus, we aimed to simulate pharmacokinetics of meloxicam and ibuprofen in pain and pain-free states using a physiological based software program to identify the underlining mechanistic changes for the observed differences.

METHOD

Published in vivo data of meloxicam and ibuprofen were used for the simulations. Two drug formulations were studied: a fast dissolving (FD) and regular release (RR) tablet formulation. The oral bioavailability was compared between these formulations in vagally suppressed rats (gastric dysfunction) and a control group. For ibuprofen additional human data of a control and post dental surgery group were used. All simulations were performed using GastroPlus™. The in vivo drug release and PK of all formulations were estimated for both drugs using the software's immediate release (IR) or gastric release (GR) models.

RESULT

For meloxicam, the IR model predicted the in vivo absorption in the control group after administration of the FD and RR formulations. When gastric dysfunction was induced, the IR model did not predict absorption while the GR model did for both formulations, FD and RR. For ibuprofen, the predictions were also very close for both formulations, using the IR model for the control group and the GR model for the vagally suppressed condition in rats and humans.

CONCLUSIONS

Gastric control of the drug release in pain/disease state was identified as the major factor causing the observed differences in the pharmacokinetics. Computer simulations of disease states can be employed to optimize drug release from dosage forms to overcome the reported shortfalls in the drug absorption.

Intranasal delivery of asenapine loaded nanostructured lipid carriers: formulation, characterization, pharmacokinetic and behavioural assessment

The aim of the present research work was to develop asenapine (ASM) loaded nanostructured lipid carriers (ANLC) for the delivery of drugs in the brain by an intranasal route to enhance therapeutic efficacy.

Structure of solid lipid nanoparticles produced by a microwave-assisted microemulsion technique

The current study investigates the structure of solid lipid nanoparticles, prepared using a recently reported microwave-assisted microemulsion technique, by multi-angle static and dynamic light scattering and small angle X-ray scattering techniques.

Characterization of Two Distinct Amorphous Forms of Valsartan by Solid-State NMR

Valsartan (VAL) is an antihypertensive drug marketed in an amorphous form. Amorphous materials can have different physicochemical properties depending on preparation method, thermal history, etc., but the nature of such materials is difficult to study by diffraction techniques. This study characterizes two different amorphous forms of valsartan (AR and AM) using solid-state NMR (SSNMR) as a primary investigation tool, supported by solution-state NMR, FT-IR, TMDSC, and dissolution tests. The two forms are found to be clearly distinct, with a significantly higher level of structural arrangement in the AR form, as observed in (13)C, (15)N, and (1)H SSNMR. (13)C and (15)N NMR indicates that the fully amorphous material (AM) contains an approximately equal ratio of cis-trans conformers about the amide bond, whereas the AR form exists mainly as one conformer, with minor conformational "defects". (1)H ultrafast MAS NMR shows significant differences in the hydrogen bonding involving the tetrazole and acid hydrogens between the two materials, while (15)N NMR shows that both forms exist as a 1,2,3,4-tetrazole tautomer. NMR relaxation times show subtle differences in local and bulk molecular mobility, which can be connected with the glass transition, the stability of the glassy material, and its response to aging. Counterintuitively the fully amorphous material is found to have a significantly lower dissolution rate than the apparently more ordered AR material.

A novel bile salts-lipase polymeric film-infused minitablet system for enhanced oral delivery of cholecalciferol

Few researchers have investigated the use of multiple physiological enhancers combined with synthetic carriers to augment delivery of nutraceuticals. The current work describes the development of an oral delivery system termed a bioactive association platform (BAP) capable of delivering nutraceutical actives from a formulation framework specifically for enhancing the in vitro and in vivo performance of model vitamin, cholecalciferol (Vitamin D₃). Synthesis of a novel triple vitamin minitablet and an optimized bile salt/lipase alginate-glycerin film provided unique oral components for inclusion in a BAP capsule. Component validation and physicochemical characterizations included comparative ex vivo permeability, chemical structure mapping, thermodynamic analysis and magnetic resonance imaging. In vitro dissolution studies of the BAP produced an area under the dissolution curve (AUC) for cholecalciferol release that was 28% greater than a conventional comparator product. A total of 84.01% of cholecalciferol was released from the BAP within 3 h versus only 59% from a comparator. Ex vivo permeation studies revealed superior cholecalciferol membrane diffusion from the triple vitamin minitablet BAP component. In vivo performance showed a greater mean change from baseline cholecalciferol to peak plasma levels (C_max) from the BAP compared to the comparator (55.66 versus 46.05 ng/mL). Cholecalciferol bioavailability was improved in vivo with an AUC_0-inf from the BAP that was 3.2× greater than the conventional product. The BAP was also superior at improving and maintaining serum levels of the main metabolite, 25-hydroxyvitamin D₃, compared to the conventional system. In vitro and in vivo results thus confirmed improvements in cholecalciferol dissolution, membrane permeability and plasma drug levels. The study results position the BAP as an ideal oral vehicle for enhanced delivery of cholecalciferol.

A novel osmotic pump-based controlled delivery system consisting of pH-modulated solid dispersion for poorly soluble drug flurbiprofen: in vitro and in vivo evaluation

In this study, a novel controlled release osmotic pump capsule consisting of pH-modulated solid dispersion for poorly soluble drug flurbiprofen (FP) was developed to improve the solubility and oral bioavailability of FP and to minimize the fluctuation of plasma concentration. The pH-modulated solid dispersion containing FP, Kollidon® 12 PF and Na2CO3 at a weight ratio of 1/4.5/0.02 was prepared using the solvent evaporation method. The osmotic pump capsule was assembled by semi-permeable capsule shell of cellulose acetate (CA) prepared by the perfusion method. Then, the solid dispersion, penetration enhancer, and suspending agents were tableted and filled into the capsule. Central composite design-response surface methodology was used to evaluate the influence of factors on the responses. A second-order polynomial model and a multiple linear model were fitted to correlation coefficient of drug release profile and ultimate cumulative release in 12 h, respectively. The actual response values were in good accordance with the predicted ones. The optimized formulation showed a complete drug delivery and zero-order release rate. Beagle dogs were used to be conducted in the pharmacokinetic study. The in vivo study indicated that the relative bioavailability of the novel osmotic pump system was 133.99% compared with the commercial preparation. The novel controlled delivery system with combination of pH-modulated solid dispersion and osmotic pump system is not only a promising strategy to improve the solubility and oral bioavailability of poorly soluble ionizable drugs but also an effective way to reduce dosing frequency and minimize the plasma fluctuation.

Synthesis, characterization and evaluation of tinidazole-loaded mPEG-PDLLA (10/90) in situ gel forming system for periodontitis treatment

Traditional in situ gel forming systems are potential applications for parenteral administration but always accompanied with burst release. To overcome this limitation, the tinidazole (TNZ)-loaded in situ gel forming system using a diblock copolymer, monomethoxy poly(ethylene glycol)-block-poly(d,l-lactide) (mPEG-PDLLA), was designed. The formulation of the mPEG-PDLLA-based TNZ in situ gel forming system contained 5% (w/w) TNZ, 0.4% glycerol, 5 ml N-methyl pyrrolidone (NMP) and 35% (w/w) mPEG-PDLLA. The in situ gel forming system showed sustained TNZ release over 192 h with low burst effect (around 7% in the first 8 h) in the in vitro release study. Additionally, in vivo studies were performed on rabbits with ligature-induced periodontitis, and the concentration of TNZ in the gingival crevicular fluid (GCF) as well as the pharmacokinetic parameters was calculated and the pharmacological effect of TNZ-loaded in situ gel forming (mPEG-PDLLA)-based system was found effective. Finally, histological studies revealed that the gel was a safe formulation with low irritation. The desirable drug release kinetics combined with the excellent in vivo characteristics highlight the potential of the gel in the treatment of periodontitis. Therefore, these results confirmed that the TNZ-loaded in situ gel forming mPEG-PDLLA-based system could reduce burst release of TNZ and act as a sustained-release and injectable drug depot for periodontitis treatment.

Sugars as solid dispersion carrier to improve solubility and dissolution of the BCS class II drug: clotrimazole

Solid dispersion of poorly soluble BCS class II drug, clotrimazole, was prepared with the aim of enhancing its dissolution profile. Solid dispersions were prepared using various sugars as carriers at different weight ratio to drug-like d-mannitol, d-fructose, d-dextrose and d-maltose by fusion method. The solubility of plain clotrimazole in different percent of sugar solutions was measured. Also, its solubility in solid dispersion and their physical mixture were assessed. The dissolution of all the prepared SD tablets, direct compressed clotrimazole tablet and plain drug were tested using the U.S. Pharmacopeia convention (USP) apparatus II. The dissolution profiles were characterized by parameters like area under curve (AUC), mean residence time (MRT), mean dissolution time (MDT) and percent dissolution efficiency (% DE). The release kinetics study was performed using DD Solver TM software. The selected solid dispersions (SDs) were evaluated for antifungal activity. A 100% solution of mannitol showed 806-fold increases in solubility as compared with plain clotrimazole in water. It was observed that the dissolution profile of clotrimazole was improved by mannitol SD at drug to sugar ration of 1:3. The percent DE value for mannitol SD tablet was found to be 77.3516% as against plain drug and directly compressed tablet of clotrimazole at 50.9439% and 31.33%, respectively. Also the antifungal activity indicated by inhibition zone was found to be 54 mm indicating enhance activity against Candida albicans as compared with plain CTZ at 6.6 mm. Thus, it can be concluded that the sugar alcohol, that is, mannitol is a more promising hydrophilic carrier for solid dispersion preparation to improve the solubility and dissolution of poorly soluble drugs.

Development of a topical adapalene-solid lipid nanoparticle loaded gel with enhanced efficacy and improved skin tolerability

The present investigation substantiates the efficacy of adapalene loaded solid lipid nanoparticles (Ada-SLNs) in ameliorating the skin irritation potential of adapalene owing to its altered skin distribution.

Systematic development of novel cationic self-nanoemulsifying drug delivery systems of candesartan cilexetil with enhanced biopharmaceutical performance

The current studies entail systematic development, optimization and evaluation of cationic self-nanoemulsifying drug delivery systems (C-SNEDDS) for enhancing the oral bioavailability of candesartan cilexetil.

Physicochemical studies on local anaesthetic loaded second generation nanolipid carriers

Effect of drug concentration on different properties of NLC.

Effect of polymer charge on the formation and stability of anti-inflammatory drug loaded nanostructured lipid carriers: physicochemical approach

Proposed model of NSAID-loaded and polymer-coated NLC along with its size dependence (), PDI (), release rate (), and absorption maxima () as well as its morphology and antibacterial activity.

Use of hydrophilic and hydrophobic polymers for the development of controlled release tizanidine matrix tablets

The aim of the present study was to develop tizanidine controlled release matrix. Formulations were designed using central composite method with the help of design expert version 7.0 software. Avicel pH 101 in the range of 14-50% was used as a filler, while HPMC K4M and K100M in the range of 25-55%, Ethylcellulose 10 ST and 10FP in the range of 15 - 45% and Kollidon SR in the range of 25-60% were used as controlled release agents in designing different formulations. Various physical parameters including powder flow for blends and weight variation, thickness, hardness, friability, disintegration time and in-vitro release were tested for tablets. Assay of tablets were also performed as specified in USP 35 NF 32. Physical parameters of both powder blend and compressed tablets such as compressibility index, angle of repose, weight variation, thickness, hardness, friability, disintegration time and assay were evaluated and found to be satisfactory for formulations K4M2, K4M3, K4M9, K100M2, K100M3, K100M9, E10FP2, E10FP9, KSR2, KSR3 & KSR9. In vitro dissolution study was conducted in 900 ml of 0.1N HCl, phosphate buffer pH 4.5 and 6.8 medium using USP Apparatus II. In vitro release profiles indicated that formulations prepared with Ethocel 10 standard were unable to control the release of drug while formulations K4M2, K100M9, E10FP2 & KSR2 having polymer content ranging from 40-55% showed a controlled drug release pattern in the above mentioned medium. Zero-order drug release kinetics was observed for formulations K4M2, K100M9, E10FP2 & KSR2. Similarity test (f2) results for K4M2, E10FP2 & KSR2 were found to be comparable with reference formulation K100M9. Response Surface plots were also prepared for evaluating the effect of independent variable on the responses. Stability study was performed as per ICH guidelines and the calculated shelf life was 24-30 months for formulation K4M2, K100M9 and E10FP2.

Design and evaluation of gastroretentive levofloxacin floating mini-tablets-in-capsule system for eradication of Helicobacter pylori

Gastroretentive levofloxacin (LVF) floating mini-tablets for the eradication of Helicobacter pylori (H. pylori) were prepared using the matrix forming polymer hydroxypropyl methylcellulose (HPMC K100M), alone or with Carbopol 940P in different ratios by wet granulation technique. Buoyancy of mini-tablets was achieved by an addition of an effervescent mixture consisting of sodium bicarbonate and anhydrous citric acid to some formulations. The prepared mini-tablets were evaluated for weight variation, thickness, friability, hardness, drug content, in vitro buoyancy, water uptake and in vitro release. The optimized formula was subjected to further studies: FT-IR, DSC analysis and in vivo examination in healthy volunteers. The prepared mini-tablets exhibited satisfactory physicochemical characteristics. Incorporation of gas-generating agent improved the floating parameters. HPMC K100M mini-tablet formulation (F1) offered the best controlled drug release (>8 h) along with floating lag time <1 s and total floating time >24 h. The obtained DSC thermograms and FT-IR charts indicated that there is no positive evidence for the interaction between LVF and ingredients of the optimized formula. The in vivo test confirmed the success of the optimized formula F1 in being retained in the stomach of the volunteers for more than 4 h. LVF floating mini-tablets based on HPMC K100M is a promising formulation for eradication of H. pylori.

Gemcitabine loaded biodegradable PLGA nanospheres for in vitro pancreatic cancer therapy

Pancreatic cancer is the fourth leading cancer with 85% mortality rate in USA alone and it is prevalent in many other developed and developing countries. Clinically, gemcitabine is prescribed as the first line chemotherapeutic drug for pancreatic cancer treatment. Gemcitabine-loaded poly(lactide-co-glycolide) (PLGA) nanospheres were synthesized and their physico-chemical properties were evaluated. The FESEM images showed that the gemcitabine loaded and blank nanospheres were 180 nm and 200 nm, respectively. The optimized encapsulation efficiency of gemcitabine was 15%. It was observed that 100% of gemcitabine was released from the PLGA nanospheres for 41 days in phosphate buffered saline (PBS) at pH7.4. The uptake of nanospheres in MiaPaCa-2 cells was studied using sulforhodamine B loaded PLGA nanospheres and our results showed that the nanospheres were taken up within 3h. Furthermore, the cytotoxicity of PLGA nanospheres loaded with gemcitabine showed a relative decrease in IC50 in MiaPaCa-2 and ASPC-1 pancreatic cancer cells in comparison to free gemcitabine. The study demonstrates that this system hold promise to improve the therapeutic efficacy of gemcitabine in vitro.

In vitro dissolution similarity factor (f2) and in vivo bioequivalence criteria, how and when do they match? Using a BCS class II drug as a simulation example

The present study examined the agreement between in vitro dissolution f2 similarity and in vivo bioequivalence criteria for BCS class II drugs. Dissolution test profiles were generated using the First-order model with varied dissolution parameters around the standard values of a reference profile. The in vivo curves were derived from in vitro dissolution profiles with the drug's pharmacokinetics parameters by numerical convolution method. The Cmax, Tmax, AUC0-t and AUC0-∞ obtained from in vivo test and reference concentration-time curves were compared, and the CmaxR (Cmax ratio), TmaxDif (Tmax difference), AUC0-tR (AUC0-t ratio) and AUC0-∞R (AUC0-∞ ratio) were determined. The relationships between CmaxR, AUC0-tR, AUC0-∞R, f2 and the First-order model parameters demonstrated that the Similarity Region 1 enclosed by the f2 contour line labeled 50 was completely within the Bioequivalence Region enclosed by the contour lines labeled 0.80 and 1.20 of AUC0-tR, AUC0-∞R, and CmaxR, and the Similarity Region 2 enclosed by the f2 contour line labeled 35 was nearly overlapped with the Bioequivalence Region, but did not exactly match. The results indicate that the public standard for in vitro dissolution f2 similarity criterion (f2⩾50) is probably slightly conservative and may be widened to an appropriate lower critical value.

Challenges and opportunities to use biowaivers to compare generics in China

Biowaivers for class I drugs according to the biopharmaceutics classification system (BCS) were first introduced in 2000. The in vitro equivalence can be used to document bioequivalence between products. This study compared the in vitro dissolution behavior of two BCS class I drugs, amoxicillin and metronidazole, which are sold in China. Identifying a reference product on the Chinese domestic market was impossible. Three 250-mg and two 500-mg amoxicillin capsules and four metronidazole tablet products were tested. None of the amoxicillin products and three of the four metronidazole tablets were found to be equivalent to each other when the same strengths were compared. The bioequivalence of products that fail the in vitro test can be established via in vivo clinical studies which are expensive and time consuming. Establishing nationally or globally accepted reference products may provide regulatory agencies with an efficient mechanism approving high quality generics.

Investigating the dissolution profiles of amoxicillin, metronidazole, and zidovudine formulations used in Trinidad and Tobago, West Indies

Trinidad and Tobago is a twin-island Republic in the Caribbean and like many developing countries, it has included generic drugs on the national drug formulary to decrease the financial burden of pharmaceutical medications. However, to ensure that medications received by patients are beneficial, generic drugs need to be interchangeable with the innovator which has demonstrated safety, efficacy, and quality. The objective of the study was to compare the dissolution profiles and weight variations for different formulations of amoxicillin, metronidazole, and zidovudine that are on the national drug formulary and marketed in Trinidad and Tobago. All the products investigated are categorized as class 1 drugs according to the Biopharmaceutics Classification System (BCS) and the dissolution profiles were assessed according to the World Health Organization (WHO) criteria for interchangeability between products. The similarity factor, f 2, was used to determine sameness between the products. No generic formulation was found to be similar to Amoxil® 500-mg capsules. The two generic products for metronidazole 200-mg tablets demonstrated more than 85% drug release within 15 min in all three of the buffers; however, their 400-mg counterparts did not fulfill this requirement. The zidovudine 300-mg tablet complied with the requirements in buffer pH 4.5 and simulated gastric fluid (SGF) but not for simulated intestinal fluid (SIF). Some Class 1 pharmaceutical formulations may possess the same active ingredient and amount of drug but may show significant differences to in vitro equivalence requirements. Nevertheless, the dissolution process is suitable to detect these variations.

Synthesis and self-assembly of amphiphilic poly(acrylicacid)–poly(ɛ-caprolactone)–poly(acrylicacid) block copolymer as novel carrier for 7-ethyl-10-hydroxy camptothecin

The process of molecular self-assembly plays a crucial role in formulation of polymeric nanoparticulated drug delivery carriers as it creates the possibility for enhanced drug encapsulation and carrier surface engineering. This study aimed to develop a novel self-assembled polymeric micelles for targeted delivery in tumor cells in order to overcome not only various drawbacks of 7-ethyl-10-hydroxy camptothecin (SN-38) but also various reported limitations of other drug delivery systems, especially low drug loading and premature release. Custom synthesized amphiphilic triblock copolymer poly(acrylic acid)–poly(ɛ-caprolactone)–poly(acrylic acid) (PAA13–PCL35–PAA13) was used to prepare kinetically stable micelles by nanoprecipitation and modified nanoprecipitation procedure. Core-shell micelles with diameter of 120–140 nm, negative zeta potential and satisfactory drug loading were produced. The prepared formulations were stable in pH range of 3–12 and in media with NaCl concentration <1 mol/l. Screening mixed level factorial 3 × 22 design identified that the process temperature as well as the type of organic solvent has influence upon the efficacy of encapsulation, particle size, dissolution rate and burst release. Fourier transform infrared and differential scanning calorimetry analyses confirmed the entrapment of the active substance into the micelles. The kinetic analysis of dissolution studies revealed that the main mechanism of drug release from the prepared formulations is Fickian diffusion. Growth inhibition studies as well as DNA fragmentation assay performed on SW-480 cell lines clearly demonstrated increased growth inhibition effect and presence of fragmented DNA in cells treated with loaded micelles compared to SN-38 solution. Altogether, these results point out to potential biomedical and clinical application of PAA–PCL–PAA systems in the future.

Pulse release of doxazosin from hydroxyethylcellulose compression coated tablet: mechanistic and in vivo study

Chronotherapeutically programmed hydroxyethylcellulose (HEC) based compression coated doxazosin tablets were prepared and the influence of disintegrants croscarmellose sodium, L-hydroxypropylcellulose (L-HPC), gellan gum on drug release and in vivo performance were investigated. Infrared spectroscopy and differential scanning calorimetric studies did not indicate any excipient incompatibility in the tablets. The disintegrants induced a continuous water influx resulting in a rapid expansion of the membrane. The subsequent formation of fractures into the coats leads to a fast drug release after an initial lag time. Release rates indicated that croscarmellose sodium and L-HPC were directly proportional to their concentration in the formulations. In vitro optimized croscarmellose sodium-HEC matrix showed significantly faster (p < 0.05) drug release (t90% = 46 min) after an initial lag of 243 min. Disintegrant-HEC blended matrices were found significantly superior (p < 0.05) in terms of in vitro release and bioavailability in comparison to plain HEC matrices. Drug release kinetics followed modified power law and Weibull model (r > 0.99). The mechanism involved in release was anomalous transport and super case II transport with matrix swelling. The pulsatile tablets showed no changes either in physicochemical appearance, drug content or in dissolution pattern during its accelerated stability studies.

A facile approach for crosslinker free nano self assembly of protein for anti-tumor drug delivery: factors' optimization, characterization and in vitro evaluation

We report crosslinker free self assembly of bovine serum albumin (BSA) and a hydrophobic payload paclitaxel (PTX), into nanoparticles by harnessing the temperature driven unfolding of protein. To systematically study the effects of various factors responsible for the key attributes of the nanoparticles, a Resolution IV design was used. 20 formulations were made with pH, temperature, time of heating before and after addition of drug, stirring rate, protein concentration, and protein to drug ratio selected as independent variables. Particle size, encapsulation efficiency, yield and zeta potential were the response variables. Perturbation and Pareto charts were used to single out the important factors, while, mathematical equations and 3D surface charts have been used to describe the relationship between dependent and independent variables. Nanoparticles with size of 188-482 nm were observed with a highly negative zeta potential of -39.5 to -21.9. Nanoparticles obtained had decent encapsulation efficiency (72.5-87.9%) with effective yield (80.0-93.8%). Validation of the mathematical models with 4 runs indicated the good prognostic ability of Resolution IV design. Spectroscopic studies suggested the non-covalent complexation between BSA and PTX as the possible mechanism of self assembly due to irreversible conformational changes in protein. Transmission Electron Microscopy (TEM) revealed spherical nanoparticles with a porous network of PTX-BSA. X-ray Diffraction (XRD) showed amorphous nature of nanoparticles. PTX release from the nanoparticles was found to be controlled release and followed Peppas-Sahlin model. In vitro cytotoxicity of PTX-BSA nanoparticles was comparable to that of Taxol after 48 h treatment. These findings suggest heat driven BSA self assembly as a viable approach to formulate cytotoxic drug carrying nanoparticles which could be efficiently used in anti-cancer therapy.

Immunosafety and chronic toxicity evaluation of monomethoxypoly(ethylene glycol)-b-poly(lactic acid) polymer micelles for paclitaxel delivery

To investigate the physicochemical properties, immunosafety and chronic toxicity of monomethoxypoly(ethylene glycol)-b-poly(lactic acid) (mPEG-PLA), a copolymer used as a carrier for paclitaxel (PTX) delivery. The H-Nuclear Magnetic Resonance (H-NMR), dynamic light scattering and fluorescence probe technique were conducted to determine the physicochemical properties of mPEG-PLA copolymer. PTX-loaded polymeric micelles were characterized regarding their particle size, entrapment efficiency (EE), drug loading (DL), in vitro drug release and hemolysis rate. The complement activation in human serum and mast cells degranulation were performed by ELISA and RBL-2H3 cell line in vitro, respectively. The chronic toxicity study was carried out on beagle dogs. The optimized PTX-loaded mPEG-PLA (40/60) micelles showed a particle size of 37 nm and EE of 98.0% with a DL of 17.0% w/w. Transmission electron microscopy (TEM) analyses showed that mPEG-PLA (40/60) micelles have spherical shape with dense core. In vitro release study showed a sustained release for 24 h, and the hemolysis study revealed that mPEG-PLA (40/60) was a safe nanocarrier for intravenous administration. mPEG-PLA (40/60) showed a lower complement activation ability compared to mPEG-PLA (50/50) and Cremophor® EL (Cr EL). Furthermore, the chronic toxicity of PTX-loaded mPEG-PLA (40/60) micelles was significantly lower than those of mPEG-PLA (50/50) and Cr EL.

Evaluation of the DDSolver software applications

When a new oral dosage form is developed, its dissolution behavior must be quantitatively analyzed. Dissolution analysis involves a comparison of the dissolution profiles and the application of mathematical models to describe the drug release pattern. This report aims to assess the application of the DDSolver, an Excel add-in software package, which is designed to analyze data obtained from dissolution experiments. The data used in this report were chosen from two dissolution studies. The results of the DDSolver analysis were compared with those obtained using an Excel worksheet. The comparisons among three different products obtained similarity factors (f₂) of 23.21, 46.66, and 17.91 using both DDSolver and the Excel worksheet. The results differed when DDSolver and Excel were used to calculate the release exponent “n” in the Korsmeyer-Peppas model. Performing routine quantitative analysis proved to be much easier using the DDSolver program than an Excel spreadsheet. The use of the DDSolver program reduced the calculation time and has the potential to omit calculation errors, thus making this software package a convenient tool for dissolution comparison.

Formulation and in vitro evaluation of size expanding gastro-retentive systems of levofloxacin hemihydrate

Size increasing (plug-type) levofloxacin hemihydrate (LVF) tablets for eradication of Helicobacter pylori (H. pylori) were prepared using in situ gel forming polymers including: gellan gum, sodium alginate, pectin and xanthan gum. Effect of cross-linkers: calcium and aluminum chloride, on the drug release was also studied. The prepared tablets were evaluated for their physicochemical parameters: weight variation, thickness, friability, hardness, drug content, water uptake and in vitro drug release. The optimized formula was subjected to further studies such as radial swelling test, FT-IR and DSC. Results revealed that LVF release depends not only on the nature of the matrix but also on the type of cross linker used to form this polymeric matrix. The addition of either calcium chloride or aluminum chloride, as cross-linkers, to gellan gum formulations significantly decreased drug release. Other polymers' formulations resulted in increased drug release upon addition of the same cross-linkers. The formula containing xanthan gum without any cross linker showed the most sustained LVF release with an increase in diameter with time, thus acting as a plug-type dosage form. IR spectra and DSC thermograms of LVF, xanthan gum, and a physical mixture of both, indicated that there was no interaction between the drug and the polymer and confirmed the drug stability.