Green micellar factorial design optimized first derivative synchronous spectrofluorimetric method for tripelennamine and diphenhydramine determination in pharmaceutical gel.

A green micellar synchronous spectrofluorimetric method was developed and validated for simultaneous determination of tripelennamine hydrochloride and diphenhydramine in bulk and combined pharmaceutical formulation. Synchronous fluorescence of tripelennamine hydrochloride and diphenhydramine was determined using Δλ = 60 nm. The first derivative of synchronous fluorescence was computed to resolve overlap in the synchronous fluorescence spectra. Tripelennamine hydrochloride was quantified at 375 nm, whereas diphenhydramine was quantified at 293 nm; each is the zero-crossing point of the other. As diphenhydramine exhibited weak native fluorescence, micelle enhancement upon incorporation of sodium dodecyl sulfate was considered. Two-level full factorial design was carried out to optimize experimental parameters. Optimum conditions involved using SDS (2% w/v) along with Teorell and Stenhagen buffer (pH 9). The method was found to be linear over the range 0.2-4.5 and 0.2-5 µg/mL for tripelennamine and diphenhydramine, respectively, with limits of detection 0.211 and 0.159 µg/mL. The method was successfully applied for simultaneous determination of tripelennamine hydrochloride and diphenhydramine in laboratory-prepared gel containing all possible excipients with mean percent recoveries ±SD 100.59 ± 0.79 and 98.99 ± 0.98 for tripelennamine hydrochloride and diphenhydramine, respectively. The proposed method was proved to be eco-friendly using different greenness assessment tools.

Development of Bitter-Taste Masked Instant Jelly Formulations of Diphenhydramine Hydrochloride with Easy-to-Consume Granules.

This study developed easy-to-consume bitter taste-masking granules for the preparation of instant jelly formulations. Composite granules containing diphenhydramine hydrochloride (DPH) and polymers were prepared via spray drying. The taste-masking effect on DPH was evaluated with acceptable linearity between DPH concentration and intensity of bitterness using an electronic tongue sensor. The results indicated that ι-carrageenan could provide the greatest suppression effect on the DPH bitterness among the polymers selected for preparing spray-dried particles (SDPs). The thixotropic index (TI) of ι-carrageenan was higher than that of the other polymers. In addition, two sulfate groups per two galactose molecules in one unit of ι-carrageenan improved interaction with DPH. Compared to κ-carrageenan, the electrostatic interaction with DPH may be stronger. Easy-to-consume SDPs with ι-carrageenan were used to prepare instant jelly formulations. The instant jelly formulation containing DPH with ι-carrageenan (3.0%) met the criteria for texture properties (hardness, adhesiveness, and cohesiveness) for patients with difficulty swallowing, as specified by the Consumer Affairs Agency. Furthermore, instant jelly enhanced the bitter taste suppression of DPH. Overall, using spray-dried granules with ι-carrageenan, this technique for preparing instant jelly formulations is simple and inhibits the bitter taste of drugs, contributing to the development of oral dosage forms suitable for patients of all ages.

Application of structural and functional pharmacokinetic analogs for physiologically based pharmacokinetic model development and evaluation.

This work provides case studies for the pharmacokinetic (PK) analog approach, where a physiologically based pharmacokinetic (PBPK) model for a target chemical (has no PK data) is evaluated using PK data from a source chemical (has existing PK data). A bottom up PBPK modeling approach (using in vitro and in silico inputs) is used to develop human oral PBPK models for caffeine and diphenhydramine. Models are evaluated using in vivo data from structural and functional PK analogs. At the end of the case studies, in vivo PK data for caffeine and diphenhydramine is introduced and both models were able to simulate plasma concentrations which agreed with the in vivo PK data. To further demonstrate that structural analogs can serve as PK analogs, in vitro metabolism and plasma protein binding was compared for a subset of structurally similar ToxCast chemicals and shown to be similar. Next steps for the PK analog approach should focus on evaluating this concept for a broader set of compounds. Using PK analogs for evaluating and establishing confidence in a PBPK model will ensure that PBPK modeling remains a viable option in animal alternative safety assessments.

Bitterness-Suppressing Effect of Umami Dipeptides and Their Constituent Amino Acids on Diphenhydramine: Evaluation by Gustatory Sensation and Taste Sensor Testing.

Diphenhydramine, a sedating antihistamine, is an agonist of human bitter taste receptor 14 (hTAS2R14). Diphenhydramine hydrochloride (DPH) was used as a model bitter medicine to evaluate whether the umami dipeptides (Glu-Glu and Asp-Asp) and their constituent amino acids (Glu, Asp) could suppress its bitterness intensity, as measured by human gustatory sensation testing and using the artificial taste sensor. Various concentrated (0.001-5.0 mM) Glu-Glu, Asp-Asp, Glu and Asp significantly suppressed the taste sensor output of 0.5 mM DPH solution in a dose-dependent manner. The effect of umami dipeptides and their constituent amino acids was tending to be ranked as follows, Asp-Asp > Glu-Glu >> Gly-Gly, and Asp > Glu >> Gly (control) respectively. Whereas human bitterness intensity of 0.5 mM DPH solution with various concentrated (0.5, 1.0, 1.5 mM) Glu-Glu, Asp-Asp, Glu and Asp all significantly reduced bitterness intensity of 0.5 mM DPH solution even though no statistical difference was observed among four substances. The taste sensor outputs and the human gustatory sensation test results showed a significant correlation. A surface plasmon resonance study using hTAS2R14 protein and these substances suggested that the affinity of Glu-Glu, Asp-Asp, Glu and Asp for hTAS2R14 protein was greater than that of Gly-Gly or Gly. The results of docking-simulation studies involving DPH, Glu-Glu and Asp-Asp with hTAS2R14, suggested that DPH is able to bind to a space near the binding position of Glu-Glu and Asp-Asp. In conclusion, the umami dipeptides Glu-Glu and Asp-Asp, and their constituent amino acids, can all efficiently suppress the bitterness of DPH.

On-Demand Manufacturing of Direct Compressible Tablets: Can Formulation Be Simplified?

PURPOSE: Oral direct compressible tablets are the most frequently used drug products. Manufacturing of tablets requires design and development of formulations, which need a number of excipients. The choice of excipients depends on the concentration, manufacturability, stability, and bioavailability of the active pharmaceutical ingredients (APIs). At MIT, we developed a miniature platform for on-demand manufacturing of direct compressible tablets. This study investigated how formulations could be simplified to use a small number of excipients for a number of different API's in which long term stability is not required. METHOD: Direct compressible tablets of five pharmaceutical drugs, Diazepam, Diphenhydramine HCl, Doxycycline Monohydrate, Ibuprofen, and Ciprofloxacin HCl, with different drug loadings, were made using direct compression in an automated small scale system.. The critical quality attributes (CQA) of the tablets were assessed for the quality standards set by the United States Pharmacopeia (USP). RESULTS: This miniature system can manufacture tablets - on-demand from crystalline API using the minimum number of excipients required for drug product performance. All drug tablets met USP quality standards after manufacturing and after 2 weeks of accelerated stability test, except for slightly lower drug release for Ibuprofen. CONCLUSIONS: On-demand tablets manufacturing where there is no need for long term stability using a flexible, miniature, automated (integrated) system will simplify pharmaceutical formulation design compared to traditional formulations. This advancement will offer substantial economic benefits by decreasing product time-to-market and enhancing quality.

Improved Extraction Repeatability and Spectral Reproducibility for Liquid Extraction Surface Analysis-Mass Spectrometry Using Superhydrophobic-Superhydrophilic Patterning.

A major problem limiting reproducible use of liquid extraction surface analysis (LESA) array sampling of dried surface-deposited liquid samples is the unwanted spread of extraction solvent beyond the dried sample limits, resulting in unreliable data. Here, we explore the use of the Droplet Microarray (DMA), which consists of an array of superhydrophilic spots bordered by a superhydrophobic material giving the potential to confine both the sample spot and the LESA extraction solvent in a defined area. We investigated the DMA method in comparison with a standard glass substrate using LESA analysis of a mixture of biologically relevant compounds with a wide mass range and different physicochemical properties. The optimized DMA method was subsequently applied to urine samples from a human intervention study. Relative standard deviations for the signal intensities were all reduced at least 3-fold when performing LESA-MS on the DMA surface compared with a standard glass surface. Principal component analysis revealed more tight clusters indicating improved spectral reproducibility for a human urine sample extracted from the DMA compared to glass. Lastly, in urine samples from an intervention study, more significant ions (145) were identified when using LESA-MS spectra of control and test urine extracted from the DMA. We demonstrate that DMA provides a surface-assisted LESA-MS method delivering significant improvement of the surface extraction repeatability leading to the acquisition of more robust and higher quality data. The DMA shows potential to be used for LESA-MS for controlled and reproducible surface extraction and for acquisition of high quality, qualitative data in a high-throughput manner.

Preparation, Characterization, and Formulation Development of Drug-Drug Protic Ionic Liquids of Diphenhydramine with Ibuprofen and Naproxen.

Diphenhydramine (DPH) has been used with ibuprofen (IBU) or naproxen (NAP) in combined therapies to provide better clinical efficacy as an analgesic and sleep aid. We discovered that DPH can form protic ionic liquids (PILs) with IBU and NAP, which opens the opportunity for a new delivery mode of these combination drugs. [DPH][IBU] and [DPH][NAP] PILs exhibit low ionicity, as confirmed by Fourier transform infrared and 1H NMR spectroscopy, and accompanied by low diffusivity, high viscosity, and poor ionic conductivity. Evaluation of pharmaceutical properties of the two PILs showed that these PILs, despite high solubility and good wettability, exhibited low dissolution rates, owing to the poor dispersion of the PIL drops and the resultant small surface area during dissolution. However, when loaded into a mesoporous carrier, the PIL-carrier composites exhibited improved dissolution rates along with excellent flow properties and easy handling. Oral capsules of both PILs were developed using such composites. Such capsule products exhibited acceptable drug release and bioavailability as demonstrated by a predictive artificial stomach-duodenum dissolution test.

Formulation Development and Evaluation of Diphenhydramine Nasal Nano-Emulgel.

The aim of present study is to formulate diphenhydramine nasal nano-emulgels, having lipophilic nano-sized interior droplets, with better penetration for targeted controlled delivery to mucous membrane. Different diphenhydramine (DPH) nasal nano-emulgels were developed having propylene glycol and olive oil (as permeation enhancers) by using RSM for optimization and then evaluated for physico-chemical characteristics and thermal stability. In-vitro drug release through cellophane membrane was conducted and results were analyzed statistically. Further, gelation, mucoadhesive stress, and ex-vivo and histopathological studies were performed on optimized formulation by using goat nasal membrane. Among all formulations, E2 showed maximum DPH release at higher concentration olive oil (4%) and lower concentration propylene glycol (PG) (25%) within 4 h. All formulations have followed first-order kinetics and drug release mechanism was Fickian diffusion. Analysis of variance (ANOVA) and multiple linear regression analysis (MLRA) were used to compare results among formulations and 3D surface plots were constructed also. Optimized formulation showed immediate prolong gelation in artificial nasal mucosa and excellent mucoadhesive property (72.5 ± 1.5 dynes/cm2). Approximately 97.1% optimized formulation was permeated through membrane within 4 h, having a high flux rate (33.19 ± 0.897 µg/cm2/min) with diffusion coefficient (0.000786 ± 4.56 × 10-5 cm2/min) while drug contents remained on mucosal membrane for 24 h. Histopathologically, change on intra-mucosal surface of excised membrane was observed due to passage of drug through it. In summary, combination of PG and olive oil in nasal DPH nano-emulgel can be utilized successfully for targeted controlled delivery. The optimized formulation has excellent permeability and prolonged residence time on mucosal surface, which prove its good anti-histaminic activity in case of allergic rhinitis.

Suppression in Bitterness Intensity of Bitter Basic Drug by Chlorogenic Acid.

The purpose of the study was to evaluate suppression of the bitterness intensity of bitter basic drugs by chlorogenic acid (CGA) using the artificial taste sensor and human gustatory sensation testing and to investigate the mechanism underlying bitterness suppression using 1H-NMR. Diphenhydramine hydrocholoride (DPH) was the bitter basic drug used in the study. Quinic acid (QNA) and caffeic acid (CFA) together form CGA. Although all three acids suppressed the bitterness intensity of DPH in a dose-dependent manner as determined by the taste sensor and in gustatory sensation tests, CFA was less effective than either CGA or QNA. Data from 1H-NMR spectroscopic analysis of mixtures of the three acids with DPH suggest that the carboxyl group, which is present in both QNA and CGA but not CFA, interact with the amine group of DPH. This study showed that the bitterness intensity of DPH was suppressed by QNA and CGA through a direct electrostatic interaction with DPH as confirmed in 1H-NMR spectroscopic analysis. CGA and QNA may therefore be useful bitterness-masking agents for the basic drug DPH.

35Cl dynamic nuclear polarization solid-state NMR of active pharmaceutical ingredients.

In this work, we show how to obtain efficient dynamic nuclear polarization (DNP) enhanced 35Cl solid-state NMR (SSNMR) spectra at 9.4 T and demonstrate how they can be used to characterize the molecular-level structure of hydrochloride salts of active pharmaceutical ingredients (APIs) in both bulk and low wt% API dosage forms. 35Cl SSNMR central-transition powder patterns of chloride ions are typically tens to hundreds of kHz in breadth, and most cannot be excited uniformly with high-power rectangular pulses or acquired under conditions of magic-angle spinning (MAS). Herein, we demonstrate the combination of DNP and 1H-35Cl broadband adiabatic inversion cross polarization (BRAIN-CP) experiments for the acquisition of high quality wideline spectra of APIs under static sample conditions, and obtain signals up to 50 times greater than in spectra acquired without the use of DNP at 100 K. We report a new protocol, called spinning-on spinning-off (SOSO) acquisition, where MAS is applied during part of the polarization delay to increase the DNP enhancements and then the MAS rotation is stopped so that a wideline 35Cl NMR powder pattern free from the effects of spinning sidebands can be acquired under static conditions. This method provides an additional two-fold signal enhancement compared to DNP-enhanced SSNMR spectra acquired under purely static conditions. DNP-enhanced 35Cl experiments are used to characterize APIs in bulk and dosage forms with Cl contents as low as 0.45 wt%. These results are compared to DNP-enhanced 1H-13C CP/MAS spectra of APIs in dosage forms, which are often hindered by interfering signals arising from the binders, fillers and other excipient materials.

Effect of Surfactants and Thickeners on the Stability of Menthol-Diphenhydramine Cream Identified by Magnetic Resonance Imaging.

A menthol-diphenhydramine cream is prepared in hospital pharmacies and then prescribed to patients for the treatment of pruritus associated with chronic kidney disease. The purpose of this study is to design a stable formulation without any concern about phase separation during its clinical use on patients. As a preventive measure against phase separation, various surfactants and thickeners were incorporated into the creams. The test creams were stored at 40°C, and then their phase separation behaviors were monitored. The key technology was magnetic resonance imaging T2 mapping. From the T2 maps, some surfactants showed a certain stabilizing effect. In addition, the data analysis using Kohonen's self-organizing map revealed that hydrophilic-lipophilic balance of the surfactant is an important factor for the stabilizing effects of the surfactants. However, as a whole, the effect of surfactant was not sufficient to improve completely the low stability. By contrast, the creams were significantly stabilized by addition of thickeners. In particular, the stabilizing effect of carbomer Hiviswako105® (H105) was very high; no phase separation was observed from the cream containing H105 even after 30 d storage at 40°C. This study also verified the combination effect of surfactants and thickeners on the improvement of the emulsion stability. In conclusion, we successfully established a stable formulation of menthol-diphenhydramine cream.

Magnetic resonance imaging study on the physical stability of menthol and diphenhydramine cream for the treatment of chronic kidney disease-associated pruritus.

A cream that contains menthol and diphenhydramine is widely prepared in hospital pharmacies and prescribed to patients for the treatment of pruritus associated with chronic kidney disease. However, there is a serious concern regarding its physical stability; therefore, we investigated this issue using magnetic resonance imaging (MRI). For a sample preparation, a menthol-containing ethanol solution was mixed with a commercial diphenhydramine cream. After storage for 7 d at 40°C, substantial phase separation into two distinct layers (upper and lower layers) was observed in the sample. This study further examined the components of the phase-separated layers using magnetic resonance (MR) spectroscopy and chemical shift selective images, and it was verified that the upper layer consisted of packed oil droplet layers, whereas the lower was an aqueous phase. Subsequently, the time-dependent phase separation of the sample at different temperatures was investigated. From the MR images, including a T2 relaxation time map and apparent diffusion coefficient maps, it was obvious that the phase separation developed further with increasing temperature; the most substantial phase separation was observed from the sample stored at 40°C, while no phase separation was detected at 25°C. In the final phase of this study, we conducted a formulation study and succeeded in improving the cream's physical stability by adding a hydrophilic surfactant to the preparation.

Formulation of Eco-friendly Medicated Chewing Gum to Prevent Motion Sickness.

An attempt was made to formulate medicated chewing gum to prevent motion sickness using natural gum base for faster onset of action and easy administration, anywhere and anytime, without access to water. To avoid the discard issue of gum cud, natural gum base of Triticum aestivum (wheat grain) was explored because of its biodegradable and biocompatible nature and easy availability. Prolamin, extracted from wheat, showed good chewing capacity, elasticity, high water retention capacity, antifungal activity, and compatibility with the drug. Formulations were prepared based on a two-factor and three-level factorial design. Amount of calcium carbonate (texturizer) and gum base were selected as independent variables. Elasticity and drug release were considered as the dependent variables. All batches were evaluated for the content uniformity, elasticity study, texture study, in vitro drug release study, and chewiness study. Results revealed that medicated chewing gum containing 80 mg of calcium carbonate and 500 mg of gum base showed good elasticity and more than 90% drug release within 16 min. Thus, this study suggested that both good elasticity and chew ability and abundant availability of wheat grain can act as a potential gum base for medicated chewing gum.

Evaluation of microcrystalline cellulose II (MCCII) as an alternative extrusion-spheronization aid.

Microcrystalline cellulose II (MCCII) is a different allomorph of MCC that can be used as a filler and a disintegrant for direct compression. MCCII was studied as new pelletization aid with the aim to prepare pellets with a faster drug release than MCCI-based pellets. MCCII-based pellets showed an immediate diphenydramineHCl release profile comparable to that of Benadryl and a faster griseofulvin release than MCCI-based pellets. MCCII offers potential to use as an alternative pelletization aid.

Evaluation of drug release profile from patches based on styrene-isoprene-styrene block copolymer: the effect of block structure and plasticizer.

We prepared pressure-sensitive adhesive (PSA) patches based on styrene-isoprene-styrene (SIS) thermoplastic elastomer using hot-melt coating method. The liquid paraffine is added in the PSA matrices as a plasticizer to moderate the PSA properties. Three drugs, methyl salicylate, capsaicin, and diphenhydramine hydrochloride are selected as model drugs. The Fourier transform infrared spectroscopy, differential scanning calorimetry test, and wide-angle X-ray diffraction test indicate a good compatibility between drugs and matrices. Peppas equation is used to describe drug release profile. Different drug-matrix absorption, as indicative of drug-matrix interaction, accounts for the variation in release profiles of different drugs. Furthermore, atomic force microscopy and rheological studies of the PSA samples are performed to investigate the effect of SIS structure and plasticizer of PSA on drug release behaviors. For methyl salicylate and capsaicin, drug diffusion in the PSA matrices is the main factor controlled by the release kinetic constant k. The high [SI] diblock content and high plasticizer amount in matrix provide the PSA with a homogeneous and soften microstructure, resulting in a high diffusion rate. But for water-soluble drugs such as diphenhydramine hydrochloride, the release rate is governed by water penetration with the competition from diffusion mechanisms.

Electron-induced dissociation of singly charged organic cations as a tool for structural characterization of pharmaceutical type molecules.

Collision-induced dissociation (CID) and electron-induced dissociation (EID) have been investigated for a selection of small, singly charged organic molecules of pharmaceutical interest. Comparison of these techniques has shown that EID carried out on an FTICR MS and CID performed on a linear ion trap MS produce complementary data. In a study of 33 molecule-cations, EID generated over 300 product ions compared to 190 product ions by CID with an average of only 3 product ions per precursor ion common to both tandem MS techniques. Even multiple stages of CID failed to generate many of the product ions observed following EID. The charge carrying species is also shown to have a very significant effect on the degree of fragmentation and types of product ion resulting from EID. Protonated species behave much like the ammonium adduct with suggestion of a hydrogen atom from the charge carrying species strongly affecting the fragmentation mechanism. Sodium and potassium are retained by nearly every product ion formed from [M + Na](+) or [M + K](+) and provide information to complement the EID of [M + H](+) or [M + NH(4)](+). In summary, EID is proven to be a fitting partner to CID in the structural elucidation of small singly charged ions and by studying EID of a molecule-ion holding different charge carrying species, an even greater depth of detail can be obtained for functional groups commonly used in synthetic chemistry.

A composite polyelectrolytic matrix for controlled oral drug delivery.

The purpose of this study was to formulate drug-loaded polyelectrolyte matrices constituting blends of pectin, chitosan (CHT) and hydrolyzed polyacrylamide (HPAAm) for controlling the premature solvation of the polymers and modulating drug release. The model drug employed was the highly water-soluble antihistamine, diphenhydramine HCl (DPH). Polyelectrolyte complex formation was validated by infrared spectroscopy. Matrices were characterized by textural profiling, porositometry and SEM. Drug release studies were performed under simulated gastrointestinal conditions using USP apparatus 3. FTIR spectra revealed distinctive peaks indicating the presence of -COO(-) symmetrical stretching (1,425-1,390 cm(-1)) and -NH (3) (+) deformation (1,535 cm(-1)) with evidence of electrostatic interaction between the cationic CHT and anionic HPAAm corroborated by molecular mechanics simulations of the complexes. Pectin-HPAAm matrices showed electrostatic attraction due to residual -NH(2) and -COO(-) groups of HPAAm and pectin, respectively. Textural profiling demonstrated that CHT-HPAAm matrices were most resilient at 6.1% and pectin-CHT-HPAAm matrices were the least (3.9%). Matrix hardness and deformation energy followed similar behavior. Pectin-CHT-HPAAm and CHT-HPAAm matrices produced type IV isotherms with H3 hysteresis and mesopores (22.46 nm) while pectin-HPAAm matrices were atypical with hysteresis at a low P/P(0) and pore sizes of 5.15 nm and a large surface area. At t (2 h), no DPH was released from CHT-HPAAm matrices, whereas 28.2% and 82.2% was released from pectin-HPAAm and pectin-CHT-HPAAm matrices, respectively. At t (4 h), complete DPH release was achieved from pectin-CHT-HPAAm matrices in contrast to only 35% from CHT-HPAAm matrices. This revealed the release-modulating capability of each matrix signifying their applicability in controlled oral drug delivery applications.

Dissipation and leaching potential of selected pharmaceutically active compounds in soils amended with biosolids.

Biosolids land application is an important pathway introducing pharmaceuticals into the environment. In this work, laboratory column and dissipation experiments were performed using soils of varying properties in order to study the fate and transport of pharmaceutical residues introduced by the land application of biosolids. For experimentation, five pharmaceutical compounds (carbamazepine, diphenhydramine, fluoxetine, diltiazem, and clindamycin) and two metabolites (carbamazepine-10,11-epoxide and norfluoxetine) commonly found in biosolids were selected. Leaching experiments indicate that the selected pharmaceuticals have low mobility in tested soils. However, small portions of the applied pharmaceuticals were recovered in the leachates, likely attributed to sorption to dissolved organic matter. Dissipation experiments show that carbamazepine, diphenhydramine, and fluoxetine were persistent in soils, whereas the dissipation of diltiazem and clindamycin was affected by redox conditions and soil properties.

Comparison between the effect of strongly and weakly cationic exchange resins on matrix physical properties and the controlled release of diphenhydramine hydrochloride from matrices.

This study focused on investigating and comparing between the effect of the strongly cationic exchange resin, Dowex 88 (Dow88), and the weakly cationic exchange resin, Amberlite IRP64 (Am64), on the physical properties of matrices and their drug release profiles. The matrices were prepared by direct compression of Methocel K4M (HPMC) or Ethocel 7FP (EC) polymeric matrix formers and contained diphenhydramine hydrochloride as a model drug. The addition of Dow88 to the matrices decreased matrix hardness and increased thickness, diameter, and friability. In contrast, the addition of Am64 increased matrix hardness and maintained the original thickness, diameter, and friability. In deionized water, both resins lowered drug release from HPMC-based matrices by virtue of the gelation property of matrix former and the drug exchange property of embedded resin, in other words in situ resinate formation. Dow88 strongly dissociated and lowered the drug release to a greater extent than Am64, which was weakly dissociated. However, Am64 could retard drug release under simulated gastrointestinal conditions. EC-based matrices containing either resin displayed a propensity for disintegration caused by swelling and wicking (water adsorption) actions by the resin. The results of this study provided useful information on the utilization of ion exchange resins as release modifiers in matrix systems.

Percutaneous Absorption of Lorazepam, Diphenhydramine Hydrochloride, and Haloperidol from ABH Gel.

The objective of this project was to study the percutaneous absorption of lorazepam, diphenhydramine hydrochloride, and haloperidol from a topical Pluronic lecithin organogel, also known as ABH gel, across the porcine ear skin and verify its suitability for topical application. ABH gel was prepared using lecithin in isopropyl palmitate solution (1:1) as an oil phase and 20% w/v Poloxamer 407 solution as an aqueous phase. The gel was characterized for pH, viscosity, drug content, and thermal behavior. A robust high-performance liquid chromatography method was developed and validated for simultaneous analysis of lorazepam, diphenhydramine hydrochloride, and haloperidol. The percutaneous absorption of lorazepam, diphenhydramine hydrochloride, and haloperidol from ABH gel was carried out using Franz cells across the Strat-M membrane and pig ear skin. The pH of ABH gel was found to be 5.66 ± 0.13. The retention time of diphenhydramine hydrochloride, haloperidol, and lorazepam was found to be 5.2 minutes, 7.8 minutes, and 18.9 minutes, respectively. The ABH gel was found to be stable for up to 30 days. Theoretical steady state plasma concentrations (CSS) of diphenhydramine hydrochloride, haloperidol, and lorazepam calculated from flux values were found to be 1.6 ng/mL, 0.13 ng/mL, and 2.30 ng/mL, respectively. The theoretical CSS of diphenhydramine hydrochloride, haloperidol, and lorazepam were much lower than required therapeutic concentrations for antiemetic activity to relieve chemotherapy-induced nausea and vomiting. From the percutaneous absorption data, it was evident that ABH gel failed to achieve required systemic levels of lorazepam, diphenhydramine hydrochloride, and haloperidol following topical application.