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1.  Identification of Phthalates in Medications and Dietary Supplement Formulations in the United States and Canada 
Environmental Health Perspectives  2011;120(3):379-384.
Background: In animal studies, some ortho-phthalates, including di(2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DBP), have been shown to be reproductive and developmental toxicants. Human studies show widespread population exposure to background levels of phthalates. Limited evidence suggests that particularly high exposure levels may result from orally ingested medicinal products containing phthalates as excipients (inactive ingredients).
Objective: In this study we aimed to identify and describe the scope of prescription (RX) and nonprescription (over-the-counter; OTC) medicinal products and dietary supplements marketed in the United States and Canada since 1995 that include phthalates as excipients.
Methods: We used lists of modified-release drug products to identify potential drug products. Inclusion of phthalates was verified using available electronic databases, print references, published package inserts, product packages, and direct communication from manufacturers. Additional products were identified using Internet searches utilizing keywords for phthalates.
Results: Based on labeling information, 6 RX drug products included DBP as an excipient, and 45 specified the use of diethyl phthalate (DEP). Phthalate polymers with no known toxicity—hypromellose phthalate (HMP), cellulose acetate phthalate (CAP), and polyvinyl acetate phthalate (PVAP)—were included in 75 RX products. Three OTC drug and dietary supplement products listed DBP, 64 listed DEP, and > 90 indicated inclusion of polymers.
Conclusions: Numerous RX and OTC drug products and supplements from a wide range of therapeutic categories may use DBP or DEP as excipients in oral dosage forms. The potential effects of human exposure to these phthalates through medications are unknown and warrant further investigation.
doi:10.1289/ehp.1103998
PMCID: PMC3295354  PMID: 22169271
coating; dietary supplements; excipients; medications; phthalates
2.  In Vitro Evaluation of Viability, Integrity, and Inflammation in Genital Epithelia upon Exposure to Pharmaceutical Excipients and Candidate Microbicides▿  
Antimicrobial Agents and Chemotherapy  2010;54(12):5105-5114.
The use of microbicides is a promising approach for the prevention of HIV-1 transmission. Unfortunately, various candidates failed in clinical trials. In some cases, the candidate microbicide even resulted in enhanced virus transmission. Therefore, there is an urgent need to develop more predictive preclinical strategies to anticipate the in vivo efficiency/toxicity rate, including in vitro assays that evaluate effects on epithelial integrity and inflammation. The present study aims to identify potential safety issues concerning the use of microbicides and excipients commonly used in vaginal microbicide preparations. The toxicities of various active pharmaceutical ingredients (APIs; TMC-120, UC-781, tenofovir [PMPA], PRO-2000, and glycerol monolaurate [GML]) and excipients (preservatives, cosolvents, surfactants, and cyclodextrins) were evaluated using an in vitro dual-chamber model and uterine cervical explants. Epithelial viability and permeation of fluorescent virus-sized beads, as well as induction of interleukin-8 (IL-8; as a sensitive marker of an inflammatory response), were assessed. Surprisingly, cell viability and epithelial layer integrity were compromised by most excipients at concentrations near the typical concentration used in vaginal gels, and a significant increase in the production of IL-8 was observed at subtoxic concentrations. Within the APIs, TMC-120, UC-781, and PMPA showed higher selectivity indices than PRO-2000 and GML. In conclusion, identification of safety issues concerning the use of pharmaceutical excipients could help to formulate less toxic vaginal microbicide preparations.
doi:10.1128/AAC.00456-10
PMCID: PMC2981258  PMID: 20921308
3.  Microbicide excipients can greatly increase susceptibility to genital herpes transmission in the mouse 
BMC Infectious Diseases  2010;10:331.
Background
Several active ingredients proposed as vaginal microbicides have been shown paradoxically to increase susceptibility to infection in mouse genital herpes (HSV-2) vaginal susceptibility models and in clinical trials. In addition, "inactive ingredients" (or excipients) used in topical products to formulate and deliver the active ingredient might also cause epithelial toxicities that increase viral susceptibility. However, excipients have not previously been tested in susceptibility models.
Methods
Excipients commonly used in topical products were formulated in a non-toxic vehicle (the "HEC universal placebo"), or other formulations as specified. Twelve hours after exposure to the excipient or a control treatment, mice were challenged with a vaginal dose of HSV-2, and three days later were assessed for infection by vaginal lavage culture to assess susceptibility.
Results
The following excipients markedly increased susceptibility to HSV-2 after a single exposure: 5% glycerol monolaurate (GML) formulated in K-Y® Warming Jelly, 5% GML as a colloidal suspension in phosphate buffered saline, K-Y Warming Jelly alone, and both of its humectant/solvent ingredients (neat propylene glycol and neat PEG-8). For excipients formulated in the HEC vehicle, 30% glycerin significantly increased susceptibility, and a trend toward increased HSV-2 susceptibility was observed after 10% glycerin, and 0.1% disodium EDTA, but not after 0.0186% disodium EDTA. The following excipients did not increase susceptibility: 10% propylene glycol, 0.18%, methylparaben plus 0.02% propylparaben, and 1% benzyl alcohol.
Conclusions
As reported with other surfactants, the surfactant/emulsifier GML markedly increased susceptibility to HSV-2. Glycerin at 30% significantly increased susceptibility, and, undiluted propylene glycol and PEG-8 greatly increased susceptibility.
doi:10.1186/1471-2334-10-331
PMCID: PMC2996397  PMID: 21087496
4.  Effects of Commonly Used Excipients on the Expression of CYP3A4 in Colon and Liver Cells 
Pharmaceutical research  2010;27(8):1703-1712.
Purpose
The objective of this investigation was to assess whether common pharmaceutical excipients regulate the expression of drug-metabolizing enzymes in human colon and liver cells.
Methods
Nineteen commonly used excipients were evaluated using a panel of experiments including cell-based human PXR activation assays, real-time RT-PCR assays for CYP3A4 mRNA expression, and immunoblot analysis of CYP3A4 protein expression in immortalized human liver cells (HepG2 and Fa2N4), human primary hepatocytes, and the intestinal LS174T cell models.
Results
No excipient activated human PXR or practically induced CYP3A4. However, three excipients (polysorbate 80, pregelatinized starch, and hydroxypropyl methylcellulose) tended to decrease mRNA and protein expression across experimental models.
Conclusion
This study represents the first investigation of the potential role of excipients in the expression of drug-metabolizing enzymes. Findings imply that some excipients may hold potential for excipient-drug interactions by repression of CYP3A4 expression.
doi:10.1007/s11095-010-0170-2
PMCID: PMC3718039  PMID: 20503067
Excipients; CYP3A4; PXR; Induction; Repression
5.  Herbal Excipients in Novel Drug Delivery Systems 
The use of natural excipients to deliver the bioactive agents has been hampered by the synthetic materials. However advantages offered by these natural excipients are their being non-toxic, less expensive and freely available. The performance of the excipients partly determines the quality of the medicines. The traditional concept of the excipients as any component other than the active substance has undergone a substantial evolution from an inert and cheap vehicle to an essential constituent of the formulation. Excipients are any component other than the active substance(s) intentionally added to formulation of a dosage form. This article gives an overview of herbal excipients which are used in conventional dosage forms as well as novel drug delivery systems.
doi:10.4103/0250-474X.44587
PMCID: PMC2792536  PMID: 20046764
Polysaccharides; volatile oils; controlled delivery
6.  Comparison of two alternative study designs in assessment of medicines utilisation in neonates 
Background
Estimates of prevalence are known to be affected by the design of cross-sectional studies. A pan-European study provided an opportunity to compare the effect of two cross-sectional study designs on estimates of medicines use.
Methods
A Service evaluation survey (SES) and a web-based point-prevalence study (PPS) were conducted as part of a European study of neonatal exposure to excipients. Neonatal units from all European Union countries plus Iceland, Norway, Switzerland and Serbia were invited to participate. All medicines prescribed to neonates were recorded during three-day and one-day study periods in the SES and PPS, respectively. In the PPS individual demographic and prescription data were also collected.
To compare the probabilities that a particular medicine would be reported by each study multilevel mixed effects logistic regression models with crossed random effects were applied. The relationship between medicines exposure at the unit and individual levels in the PPS data was assessed using polynomial regression with square root transformation.
Results
Of 31 invited countries 20 and 21 with 115 and 89 units joined the SES and PPS, respectively. Out of 5,572,859 live births in invited countries in 2010 a higher proportion was covered by units participating in the SES compared to the PPS (11% vs 6%, respectively; OR 1.89; 95% CI 1.87-1.89). A greater number of active pharmaceutical ingredients (API), manufacturers and trade names were registered in the SES compared to the PPS. High correlation between the two studies in frequency of use for each specified API was seen (R2 = 0.86). The average probability of a department to use a given API was greater in the SES compared to the PPS (OR 2.36; 95% CI 2.05-2.73) with higher frequency of use and longer average duration of prescription further increasing the difference. The polynomial regression model described the correlation between APIs exposure on unit and individual level well (R2 = 0.93).
Conclusion
The simple data structure and longer study period of the SES resulted in improved recruitment and higher likelihood of capture for a given API. The frequency of use at the unit level appears a good surrogate of individual exposure rates.
doi:10.1186/1471-2288-14-89
PMCID: PMC4110064  PMID: 25027048
Pharmacoepidemiologic methods; Cross-sectional studies; Data collection; Drug/excipient exposure
7.  Thermal behaviour of procaine and benzocaine Part II: compatibility study with some pharmaceutical excipients used in solid dosage forms 
Background
The compatibility study of active substances with excipients finds an important role in the domain of pharmaceutical research, being known the fact that final formulation is the one administered to the patient. In order to evaluate the compatibility between active substance and excipients, different analytical techniques can be used, based on their accuracy, reproducibility and fastness.
Results
Compatibility study of two well-known active substances, procaine and benzocaine, with four commonly used excipients, was carried out employing thermal analysis (TG/DTG/HF) and Fourier Transform Infrared Spectroscopy (UATR-FT-IR). The selected excipients were microcrystalline cellulose, lactose monohydrate, magnesium stearate and talc. Equal proportion of active substance and excipients (w/w) was utilized in the interaction study. The absolute value of the difference between the melting point peak of active substances and the one corresponding for the active substances in the analysed mixture, as well the absolute value of the difference between the enthalpy of the pure active ingredient melting peak and that of its melting peak in the different analysed mixtures were chosen as indexes of the drug-excipient interaction degree. All the results obtained through thermal analysis were also sustained by FT-IR spectroscopy.
Conclusions
The corroboration of data obtained by thermal analysis with the ones from FT-IR spectroscopy indicated that no interaction occurs between procaine and benzocaine, with microcrystalline cellulose and talc, as well for the benzocaine-lactose mixture. Interactions were confirmed between procaine and benzocaine respectively and magnesium stearate, and for procaine and lactose.
doi:10.1186/1752-153X-7-140
PMCID: PMC4015284  PMID: 23962059
Procaine; Benzocaine; Excipients; Compatibility studies; TG/DTG/HF
8.  Preliminary Studies on Validation of Calu-3 Cell Line as a Model for Screening Respiratory Mucosa Irritation and Toxicity 
Pharmaceutics  2014;6(2):268-280.
There is need to develop reproducible methods and experimental models for screening mucosal irritation and toxicity for drugs and pharmaceutical excipients. The aim of this study was to validate Calu-3 cell line as a model for screening respiratory irritation and toxicity of drugs and excipients. Eighteen test compounds were selected according to their irritation potential and European Centre for the Validation of Alternative Methods (ECVAM) guidelines. Cell toxicity and irritation was determined using MTT assay. Data analysis and interpretation were done using modified ECVAM approach; where replicate values met acceptance criteria if percent relative standard deviation (RSD) of the raw data is <18%. Compounds with mean relative viability values of 50% and below were classified as irritant (I); those above 50% were non-irritant (NI). At low concentration (0.2% w/v) and 1 h incubation, the Calu-3 cell culture model accurately predicted the toxicity of most test compounds. The specificity of our proposed model (percentage of in vivo non-irritants correctly predicted), concordance (percentage of compounds correctly predicted) and sensitivity (percentage of in vivo irritants correctly predicted) at 0.2% w/v and 60 min exposure were 100%, 72%, and 44%, respectively. In conclusion, the Calu-3 cell line in conjunction with MTT assay appears to be a potentially useful tool for screening drugs and excipients for respiratory mucosa irritation and toxicity. However, as the data reported in this study were solely based on MTT assay, additional studies are needed using other toxicity-/irritation-indicating methods to confirm the observed trend.
doi:10.3390/pharmaceutics6020268
PMCID: PMC4085599  PMID: 24962675
Calu-3 cells; MTT; toxicity prediction; mucosal toxicity
9.  Reactive Impurities in Excipients: Profiling, Identification and Mitigation of Drug–Excipient Incompatibility 
AAPS PharmSciTech  2011;12(4):1248-1263.
Reactive impurities in pharmaceutical excipients could cause drug product instability, leading to decreased product performance, loss in potency, and/or formation of potentially toxic degradants. The levels of reactive impurities in excipients may vary between lots and vendors. Screening of excipients for these impurities and a thorough understanding of their potential interaction with drug candidates during early formulation development ensure robust drug product development. In this review paper, excipient impurities are categorized into six major classes, including reducing sugars, aldehydes, peroxides, metals, nitrate/nitrite, and organic acids. The sources of generation, the analytical method for detection, the stability of impurities upon storage and processing, and the potential reactions with drug candidates of these impurities are reviewed. Specific examples of drug–excipient impurity interaction from internal research and literature are provided. Mitigation strategies and corrective measures are also discussed.
doi:10.1208/s12249-011-9677-z
PMCID: PMC3225520  PMID: 21948318
excipients; impurities; interaction; mitigation; variability
10.  Analysis of Structural Variability in Pharmaceutical Excipients Using Solid-State NMR Spectroscopy 
AAPS PharmSciTech  2011;12(3):821-833.
Polysaccharide-based excipients comprise the majority of most solid dosage forms and can vary dramatically in terms of structural and functionally related properties. Analytical methods for characterizing these important formulation components are crucial. Solid-state NMR spectroscopy (SSNMR) can provide a wealth of information on these materials while offering the advantages of non-destructive sample preparation and selectivity. The overall objective of this work is to identify SSNMR parameters that can be used to detect differences among these excipients. Excipients were obtained from a wide range of suppliers and analyzed as received; 13C SSNMR spectra were acquired using a Chemagnetics CMX-300 spectrometer operating at approximately 75 MHz. The resolution of SSNMR signals of many excipients allows for positive identification of the major form present. Alginic acid and sodium alginate can be differentiated based on carbonyl peak position. Analysis of relative peak intensities provides insight into the purity of a carrageenan sample compared to known standards. The SSNMR spectrum of starch can be used to identify the source and to quantitate the amorphous and crystalline content. Relaxation values and peak areas of starch derivatives can be related to the degree of hydrolysis, providing an alternative method for determining dextrose equivalent. Differences in peak intensities and relaxation time values of HPMC samples can be correlated to the amount of methoxy subsituent groups. Important characteristics of excipients such as form identification, structural differences, crystalline and amorphous content, and water content variations can be detected using SSNMR spectroscopy.
doi:10.1208/s12249-011-9637-7
PMCID: PMC3167250  PMID: 21710337
excipients; polysaccharide; relaxation time; solid-state NMR spectroscopy
11.  Neonates need tailored drug formulations 
Drugs are very strong tools used to improve outcome in neonates. Despite this fact and in contrast to tailored perfusion equipment, incubators or ventilators for neonates, we still commonly use drug formulations initially developed for adults. We would like to make the point that drug formulations given to neonates need to be tailored for this age group. Besides the obvious need to search for active compounds that take the pathophysiology of the newborn into account, this includes the dosage and formulation. The dosage or concentration should facilitate the administration of low amounts and be flexible since clearance is lower in neonates with additional extensive between-individual variability. Formulations need to be tailored for dosage variability in the low ranges and also to the clinical characteristics of neonates. A specific focus of interest during neonatal drug development therefore is a need to quantify and limit excipient exposure based on the available knowledge of their safety or toxicity. Until such tailored vials and formulations become available, compounding practices for drug formulations in neonates should be evaluated to guarantee the correct dosing, product stability and safety.
doi:10.5409/wjcp.v2.i1.1
PMCID: PMC4145637  PMID: 25254168
Drug formulation; Newborn; Excipient; Safety; Quality control
12.  Excipient selection can significantly affect solid-state phase transformation in formulation during wet granulation 
AAPS PharmSciTech  2005;6(2):E311-E322.
Phase transformations in formulations can lead to instability in physicochemical, biopharmaceutical, and processing properties of products. The influences of formulation design on the optimal dosage forms should be specified. The aim here was to investigate whether excipients with different water sorption behavior affect hydrate formation of nitrofurantoin in wet masses. Nitrofurantoin anhydrate was used as a hydrate-forming model drug, and 4 excipients with different water-absorbing potential (amorphous low-substituted hydroxypropylcellulose, modified maize starch, partially amorphous silicified microcrystalline cellulose, and crystalline α-lactose monohydrate) were granulated with varying amounts of purified water. Off-line evaluation of wet masses containing nitrofurantoin anhydrate and excipient (1∶1) was performed using an X-ray powder diffractometer (XRPD) and near-infrared spectroscopy, and drying phase was evaluated by variable temperature XRPD. Only amorphous excipient in the formulation retarded hydrate formation of an active pharmaceutical ingredient (API) at high water contents. Hygroscopic partially crystalline excipient hindered hydrate formation of API at low water contents. Crystalline excipient was unable to control hydrate formation of API. The character of excipient affects the stability of formulation. Thus, correct selection of excipients for the formulation can control processing-induced phase transitions and improve the storage stability of the final dosage form.
doi:10.1208/pt060241
PMCID: PMC2750544  PMID: 16353990
nitrofurantoin; near-infrared spectroscopy; sorption; X-ray powder diffraction
13.  Design and development of a stable polyherbal formulation based on the results of compatibility studies 
Pharmacognosy Research  2011;3(2):122-129.
Introduction:
Ayurvedic and herbal medicinal products contain a combination of botanicals; each of these contains a number of chemical compounds that may give the anticipated activity in combination. Therefore, it is very important to analyze and evaluate the compatibility of various active constituents and markers from different medicinal plants for their possible chemical interactions with various excipients at different storage conditions during the development of a stable polyherbal formulation.
Objective:
To study chemical stability of kalmegh (Andrographis paniculata) and kutki (Picrorhiza kurroa) extract for their active markers andrographolide, kutkoside and picroside-I and to develop stable polyherbal formulation based on the incompatibility studies.
Materials and Methods:
The compatibility study was carried out on individual ethanolic extracts of these two plants along with the commonly used excipients in the ratio of 1:1 at 40 ± 2°C and 75 ± 5% relative humidity and at a refrigeration temperature of 5 ± 1°C for initial, 7-, 15- and 30-day intervals. The analysis was carried out using the validated reverse phase–high-performance liquid chromatography methods. A stable tablet dosage form was developed based on the results of these studies.
Result:
The study suggested that the active markers of kutki (kutkoside and picroside-I) were found to be degraded in the presence of the kalmegh extract. However, the active marker of the kalmegh extract (andrographolide) was found to be stable. Both the extracts showed excellent compatibility with all the excipients used in making this formulation. No significant decrease in the kutkoside and picroside-I content from the formulation was observed.
Conclusion:
By separate granulation process the exposure of both the extracts can be minimized thus avoiding the degradation of active markers.
doi:10.4103/0974-8490.81960
PMCID: PMC3129021  PMID: 21772756
Compatibility; andrographolide; kutkoside; picroside-I
14.  The use of natural and synthetic phospholipids as pharmaceutical excipients* 
In pharmaceutical formulations, phospholipids obtained from plant or animal sources and synthetic phospholipids are used. Natural phospholipids are purified from, e.g., soybeans or egg yolk using non-toxic solvent extraction and chromatographic procedures with low consumption of energy and minimum possible waste. Because of the use of validated purification procedures and sourcing of raw materials with consistent quality, the resulting products differing in phosphatidylcholine content possess an excellent batch to batch reproducibility with respect to phospholipid and fatty acid composition. The natural phospholipids are described in pharmacopeias and relevant regulatory guidance documentation of the Food and Drug Administration (FDA) and European Medicines Agency (EMA). Synthetic phospholipids with specific polar head group, fatty acid composition can be manufactured using various synthesis routes. Synthetic phospholipids with the natural stereochemical configuration are preferably synthesized from glycerophosphocholine (GPC), which is obtained from natural phospholipids, using acylation and enzyme catalyzed reactions. Synthetic phospholipids play compared to natural phospholipid (including hydrogenated phospholipids), as derived from the number of drug products containing synthetic phospholipids, a minor role. Only in a few pharmaceutical products synthetic phospholipids are used. Natural phospholipids are used in oral, dermal, and parenteral products including liposomes. Natural phospholipids instead of synthetic phospholipids should be selected as phospholipid excipients for formulation development, whenever possible, because natural phospholipids are derived from renewable sources and produced with more ecologically friendly processes and are available in larger scale at relatively low costs compared to synthetic phospholipids.
Practical applications: For selection of phospholipid excipients for pharmaceutical formulations, natural phospholipids are preferred compared to synthetic phospholipids because they are available at large scale with reproducible quality at lower costs of goods. They are well accepted by regulatory authorities and are produced using less chemicals and solvents at higher yields. In order to avoid scale up problems during pharmaceutical development and production, natural phospholipid excipients instead of synthetic phospholipids should be selected whenever possible.
doi:10.1002/ejlt.201400219
PMCID: PMC4207189  PMID: 25400504
Emulsifier; Lecithin; Liposomes; Natural phospholipids; Phosphatidylcholine; Solubilizer; Synthetic phospholipids
15.  Influence of Formulation and Processing Factors on Stability of Levothyroxine Sodium Pentahydrate 
AAPS PharmSciTech  2010;11(2):818-825.
Stability of formulations over shelf-life is critical for having a quality product. Choice of excipients, manufacturing process, storage conditions, and packaging can either mitigate or enhance the degradation of the active pharmaceutical ingredient (API), affecting potency and/or stability. The purpose was to investigate the influence of processing and formulation factors on stability of levothyroxine (API). The API was stored at long-term (25°C/60%RH), accelerated (40°C/75%RH), and low-humidity (25°C/0%RH and 40°C/0%RH) conditions for 28 days. Effect of moisture loss was evaluated by drying it (room temperature, N2) and placed at 25°C/0%RH and 40°C/0%RH. The API was incubated with various excipients (based on package insert of marketed tablets) in either 1:1, 1:10, or 1:100 ratios with 5% moisture at 60°C. Commonly used ratios for excipients were used. The equilibrium sorption data was collected on the API and excipients. The API was stable in solid state for the study duration under all conditions for both forms (potency between 90% and 110%). Excipients effect on stability varied and crospovidone, povidone, and sodium laurel sulfate (SLS) caused significant API degradation where deiodination and deamination occurred. Moisture sorption values were different across excipients. Crospovidone and povidone were hygroscopic whereas SLS showed deliquescence at high RH. The transient formulation procedures where temperature might go up or humidity might go down would not have major impact on the API stability. Excipients influence stability and if possible, those three should either be avoided or used in minimum quantity which could provide more stable tablet formulations with minimum potency loss throughout its shelf-life.
doi:10.1208/s12249-010-9434-8
PMCID: PMC2902299  PMID: 20454876
excipients; formulation; levothyroxine sodium pentahydrate; moisture sorption; stability
16.  Evaluation of Gum of Moringa oleifera as a Binder and Release Retardant in Tablet Formulation 
The present study was undertaken to find out the potential of gum from Moringa oleifera to act as a binder and release retardant in tablet formulations. The effect of calcium sulphate dihydrate (water insoluble) and lactose (water soluble) diluent on the release of propranolol hydrochloride was studied. The DSC thermograms of drug, gum and mixture of gum/drug indicated no chemical interaction. Tablets (F1, F2, F3, and F4) were prepared containing calcium sulphate dihydrate as diluent, propranolol hydrochloride as model drug using 10%, 8%, 6% and 4% w/v of gum solution as binder. Magnesium stearate was used as lubricant. Physical and technological properties of granules and tablets like flow rate, Carr index, Hausner ratio, angle of repose, hardness, friability and disintegration time were determined and found to be satisfactory. Tablets were prepared by wet granulation method containing calcium sulphate dihydrate as excipient, propranolol hydrochloride as model drug using 10%, 20% and 30% of gum as release retardant, magnesium stearate was used as lubricant. Similarly tablets were prepared replacing lactose with calcium sulphate dihydrate. Despite of the widely varying physico-chemical characteristics of the excipients, the drug release profiles were found to be similar. The drug release increased with increasing proportions of the excipient and decreased proportion of the gum irrespective of the solubility characteristics of the excipient. The values of release exponent ‘n’ are between 0.37 and 0.54. This implies that the release mechanism is Fickian. There is no evidence that the dissolution or erosion of the excipient has got any effect on the release of the drug. The t50% values for tablets containing calcium sulphate dihydrate were on an average 10%-15% longer than the tablets containing lactose as excipient. These relatively small differences in t50% values suggest that the nature of excipient used appeared to play a minor role in regulating the release, while the gum content was a major factor.
doi:10.4103/0250-474X.45400
PMCID: PMC3038286  PMID: 21394258
Binder; gum; Moringa oleifera; release retardant; tablet
17.  The Molecular Chaperone α-Crystallin as an Excipient in an Insulin Formulation 
Pharmaceutical Research  2010;27(7):1337-1347.
ABSTRACT
Purpose
To investigate insulin fibrillation under accelerated stress conditions in the presence of a novel excipient, the molecular chaperone α-crystallin, in comparison with common excipients.
Methods
To induce fibrillation, recombinant human insulin (0.58 mg ml−1) formulations without excipient or with bovine α-crystallin (0.01–0.2 mg ml−1), human serum albumin (1–5 mg ml−1), sucrose (10–100 mg ml−1) or polysorbate 80 (0.075–0.3 mg ml−1) were subjected to stirring stress in a fluorescence well plate reader and formulation vials. Protein fibrillation was monitored by thioflavin T. The formulations were further characterized by size-exclusion chromatography, light obscuration, UV/Vis and circular dichroism spectroscopy.
Results
In both methods, insulin formed thioflavin T-binding species, most likely fibrils. Addition of α-crystallin in the well plate assay greatly improved insulin’s resistance to fibrillation, measured as a 6-fold increase in fibrillation lag time for the lowest and 26-fold for the highest concentration used, whereas all other excipients showed only a marginal increase in lag time. The stabilizing effect of α-crystallin was shown by all characterization techniques used.
Conclusions
The effect of α-crystallin on insulin’s physical stability outperforms that of commonly used excipients. α-Crystallin is proposed to bind specifically to pre-fibrillation species, thereby inhibiting fibrillation. This makes α-crystallin an interesting excipient for proteins with propensity to fibrillate.
doi:10.1007/s11095-010-0116-8
PMCID: PMC2883933  PMID: 20333453
fibrillation; formulation design; insulin; protein excipients; α-crystallin
18.  The Placebo Effect – Plugging the Nostrils of Unmet Needs 
Many common therapies of rhinitis symptoms are inadequate or ineffective. In part, this may be because the drug does not address the pathologically altered mechanism of the rhinopathy. Objective measures may not detect treatment effects, or the treatment endpoints may only be subjective in nature. In many cases, these issues have not arisen because of potent placebo effects. Understanding the psychological, pharmacological, and physiological components of placebos is important for separating true treatment effects from those of the excipients in the vehicle. Separating the wasteful and potentially harmful effects of those excipients from the harmless and often partially beneficial effects on temporary symptom control is an important issue in clinical pharmacology, and can aid in effective clinical trials design, use of objective and subjective test measures, and drug development in rhinitis.
PMCID: PMC4209302  PMID: 19210905
19.  Importance and globalization status of good manufacturing practice (GMP) requirements for pharmaceutical excipients 
Pharmaceutical excipients are no longer inert materials but it is effective and able to improve the characteristics of the products’ quality, stability, functionality, safety, solubility and acceptance of patients. It can interact with the active ingredients and alter the medicament characteristics. The globalization of medicines’ supply enhances the importance of globalized good manufacturing practice (GMP) requirements for pharmaceutical excipients. This review was intended to assess the globalization status of good manufacturing practice (GMP) requirements for pharmaceutical excipients. The review outcomes demonstrate that there is a lack of accurately defined methods to evaluate and measure excipients’ safety. Furthermore good manufacturing practice requirements for excipients are not effectively globalized.
doi:10.1016/j.jsps.2013.06.003
PMCID: PMC4310996
Globalization; Importance of pharmaceutical excipients; Good manufacturing practice; Excipient’s evaluation; Excipient’s Safety
20.  Development of co-processed excipients in the design and evaluation of atorvastatin calcium tablets by direct compression method 
Introduction:
Co-processed excipients were prepared to improve the process ability and efficacy of commonly used excipients and to impart multi-functional qualities to the excipients and hence that the tablets with the desired attributes can be produced. In this study, acacia and calcium carbonate (CaCO3) were used to prepare a co-processing excipient suitable for the preparation of atorvastatin calcium tablets. Acacia is used as binder and CaCO3 as filler. CaCO3 also acts as alkalizer and thus suitable to improve the dissolution rate of pH dependent soluble drugs like atorvastatin.
Materials and Methods:
The tablets were prepared by direct compression method and the physical properties of tablets such as hardness, friability and dissolution profiles of tablets were evaluated. Acacia was used in the form of mucilage. Various ratios of the co-processing excipients were formulated by granulation technique and the blend properties were evaluated by their Hausner's ratio and Carr's index values. Based on the Kawakita plots, it was found that the formulation with 3% acacia mucilage (0.9 mg acacia and 26.6 mg of CaCO3) showed good fluidity and the formulations with 4% (1.27 mg of acacia and 26.23 mg of CaCO3) and 5% acacia mucilage (1.62 mg of acacia and 25.88 mg of CaCO3) showed more cohesiveness. The formulations include 1-5% of the acacia mucilage as the binding agent.
Results:
The granules of formulations with low percentage of acacia mucilage (1% and 2%) failed the test for friability. The granules of the formulations with pure acacia (F1) and pure CaCO3 (F2) showed passable flow properties.
Conclusion:
The formulation with 3% acacia mucilage (F3, 0.9 mg acacia and 26.6 mg of CaCO3) showed least dissolution time (<1 min) and is found as the best formulation among the other formulations containing 4% (F4, 1.27 mg of acacia and 26.23 mg of CaCO3) and 5% (F5, 1.62 mg of acacia and 25.88 mg of CaCO3) acacia mucilage.
doi:10.4103/2230-973X.133059
PMCID: PMC4083533  PMID: 25006555
Acacia; alkalizer; calcium carbonate; granulation technique
21.  Intrinsic Fibrillation of Fast-Acting Insulin Analogs 
Background
Aggregation of insulin into insoluble fibrils (fibrillation) may lead to complications for diabetes patients such as reduced insulin potency, occlusion of insulin delivery devices, or potentially increased immunological potential.
Even after extensive investigation of fibril formation in regular human insulin, there are little published data about the intrinsic fibrillation of fast-acting analogs. This article investigates and compares the intrinsic fibrillation of three fast-acting insulin analogs—lispro, aspart, and glulisine—as a function of their primary protein structure and exclusive of the stabilizing excipients that are added to their respective commercial formulations.
Methods
The insulin analogs underwent a buffer exchange into phosphate-buffered saline to remove formulation excipients and then were heated and agitated to characterize intrinsic fibrillation potentials devoid of excipient stabilizing effects. Different analytical methods were used to determine the amount of intrinsic fibrillation for the analogs. After initial lag times, intrinsic fibrillation was detected by an amyloid-specific stain. Precipitation of insulin was confirmed by ultraviolet analysis of soluble insulin and gravimetric measurement of insoluble insulin. Electron microscopy showed dense fibrous material, with individual fibrils that are shorter than typical insulin fibrils. Higher resolution kinetic analyses were carried out in 96-well plates to provide more accurate measures of lag times and fibril growth rates.
Results
All three analogs exhibited longer lag times and slower intrinsic fibrillation rates than human insulin, with glulisine and lispro rates slower than aspart. This is the first study comparing the intrinsic fibrillation of fast-acting insulin analogs without the stabilizing excipients found in their commercial formulations.
Conclusions
Data show different intrinsic fibrillation potentials based on primary molecular structures when the formulation excipients that are critical for stability are absent. Understanding intrinsic fibrillation potential is critical for evaluating insulin analog stability and device compatibility.
PMCID: PMC3380767  PMID: 22538135
amyloid; circular dichroism; excipients; fibrils; insulin; insulin stability; intrinsic fibrillation; protein aggregation; protein precipitation; thioflavine T
22.  The importance of implementing proper selection of excipients in lupus clinical trials 
Lupus  2014;23(7):609-614.
Peptide therapeutics hold attractive potential. However, the proper stabilization of such therapeutics remains a major challenge. Some peptides are marginally stable and are prone to degradation. Therefore, in addition to chemical modifications that can be introduced in their sequence, a wide variety of excipients are added in the formulation to stabilize them, as is also done routinely for protein therapeutics. These substances are supposed to suppress peptide/protein aggregation and surface adsorption, facilitate their dispersion and additionally to provide physiological osmolality. Particular attention has to be paid to the choice of such excipients. Here we highlight the observation that in certain clinical situations, an excipient that is not totally inert can play a highly damaging role and mask (or even reverse) the beneficial effect of a molecule in clinical evaluation. This is the case, for instance, of trehalose, a normally safe excipient, which notably has proven to act as an activator of autophagy. This excipient, although used efficiently in several therapeutics, adversely impacted a phase IIb clinical trial for human and murine lupus, a systemic autoimmune disease in which it has been recently discovered that at the base line, autophagy is already abnormally enhanced in lymphocytes. Thus, in this particular pathology, while the peptide that was tested was active in lupus patients when formulated in mannitol, it was not efficient when formulated in trehalose. This observation is important, since autophagy is enhanced in a variety of pathological situations, such as obesity, diabetes, certain neurological diseases, and cancer.
doi:10.1177/0961203314525249
PMCID: PMC4232263  PMID: 24569394
Excipients; trehalose; clinical trials; systemic lupus erythematosus; P140/Lupuzor; autophagy
23.  Free radicals and the pH of topical glaucoma medications: a lifetime of ocular chemical injury? 
Eye  2012;26(5):734-741.
Introduction
Preservatives in ophthalmic preparations are known to cause ocular surface damage. Excipients can also contribute to oxidative stress in the compromised ocular surface. We evaluated commonly used topical glaucoma medications to ascertain pH levels and the intrinsic presence of free radicals.
Methods
Samples of 27 topical glaucoma preparations were analysed for total free radical presence using a Randox Kit for total antioxidant status. Analytical grade indicator paper was used to ascertain pH levels.
Results
Free radical concentrations for these 27 glaucoma preparations ranged from 0 to 4.54 mmol/l, with a median value of 0.66 mmol/l (mean value of 0.662 mmol/l, SD 0.839). Levels of pH ranged from 4.0 to 7.4, with a median value of 6.5 (mean 6.252, SD 0.826). There was no evidence of a direct correlation between these two variables (r=0.232, P=0.275).
Conclusion
This study is the first to document the range of pH and concentrations of free radicals intrinsically present in commonly used glaucoma medications. Long-term exposure to preservatives, free radicals, and pH levels could all contribute to ocular surface damage. The effect of excipients could be responsible for patient intolerance when changing products in the compromised ocular surface.
doi:10.1038/eye.2012.25
PMCID: PMC3351058  PMID: 22388593
free radicals; preservatives; ocular surface; pH; glaucoma; topical medications
24.  Randomized, double-blind, placebo-controlled and active-controlled study to assess the relative abuse potential of oxycodone HCl-niacin tablets compared with oxycodone alone in nondependent, recreational opioid users 
Background
Abuse-deterrent formulations attempt to address public health and societal concerns regarding opioid abuse. Oxycodone HCl-niacin tablets combine oxycodone HCl with niacin and functional inactive excipients to create potential barriers to oral, intranasal, and intravenous abuse. This study compared the relative abuse potential of oral immediate-release oxycodone HCl-niacin with that of oral immediate-release oxycodone HCl and placebo in nondependent, recreational opioid users.
Methods
Forty-nine participants received oxycodone HCl-niacin 40/240 mg and 80/480 mg, oxycodone 40 mg and 80 mg, and placebo in a randomized, double-blind, placebo-controlled and active-controlled, five-way crossover study. Primary endpoints based on a bipolar 100 mm visual analog scale for drug liking were area under effect curve (AUE0–1h, AUE0–2h, AUE0–3h), peak disliking, and effect at 0.5 hours post-dose (E0.5h). Other endpoints included take drug again assessment, overall drug liking, and pupillometry.
Results
There were statistically significant differences between oxycodone HCl-niacin and oxycodone HCl doses for all primary endpoints (P < 0.0001, all comparisons), suggesting reduced abuse potential with oxycodone HCl-niacin. Take drug again and overall drug liking showed greater liking of oxycodone alone. Oxycodone HCl-niacin 80/480 mg had consistently lower liking assessments than oxycodone HCl-niacin 40/240 mg, suggesting a dose-response to the aversive effects of niacin. Opioid-related adverse events were similar for equivalent oxycodone doses. The treatment-emergent adverse events most specifically associated with oxycodone HCl-niacin (ie, skin-burning sensation, warmth, and flushing) were consistent with the expected vasocutaneous effects of niacin. No serious adverse events were reported.
Conclusion
Oxycodone HCl-niacin tablets may, in a dose-dependent manner, decrease the potential for oral abuse of oxycodone without unexpected adverse events or clinically signifi-cant differences in safety parameters compared with oxycodone alone. Although statistically powered, the small size of the study sample and the characteristics of its participants may not be generalizable to the population that abuses prescription opioid medications.
doi:10.2147/SAR.S33080
PMCID: PMC3886648  PMID: 24474870
drug abuse; opioid; oxycodone; niacin
25.  Topical Formulations of Serratiopeptidase: Development and Pharmacodynamic Evaluation 
Serratiopeptidase, an enzyme derived from Serratia marcescences strain E-15 (ATCC 21074), present in the gut wall of the silk worm possesses anti-inflammatory properties, and can prove to be a suitable alternative to commonly used non steroidal antiinflammatory agents. Being sensitive to gastric degradation, serratiopeptidase is conventionally given orally in the form of enteric coated tablet formulations. Topical formulations of serratiopeptidase would be useful to treat local inflammations and may prove to be more effective compared to non steroidal antiinflammatory agents. The present study investigates the feasibility of developing topical preparations of serratiopeptidase in the form of ointments and gels. Excipient compatibility of serratiopeptidase with various excipients and polymers, formulation development, characterization and stability studies have been carried out. Stable formulation was evaluated for anti-inflammatory activity by oxazolone induced ear edema method in mice and allergenic potential by passive cutaneous anaphylaxis.
doi:10.4103/0250-474X.62246
PMCID: PMC2883229  PMID: 20582192
Antiinflammatory; gel; ointment; serratiopeptidase

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