Pathways for Oral and Rectal Delivery of Gold Nanoparticles (1.7 nm) and Gold Nanoclusters into the Colon: Enteric-Coated Capsules and Suppositories

Two ways to deliver ultrasmall gold nanoparticles and gold-bovine serum albumin (BSA) nanoclusters to the colon were developed. First, oral administration is possible by incorporation into gelatin capsules that were coated with an enteric polymer. These permit the transfer across the stomach whose acidic environment damages many drugs. The enteric coating dissolves due to the neutral pH of the colon and releases the capsule's cargo. Second, rectal administration is possible by incorporation into hard-fat suppositories that melt in the colon and then release the nanocarriers. The feasibility of the two concepts was demonstrated by in-vitro release studies and cell culture studies that showed the easy redispersibility after dissolution of the respective transport system. This clears a pathway for therapeutic applications of drug-loaded nanoparticles to address colon diseases, such as chronic inflammation and cancer.

Achievements in Thermosensitive Gelling Systems for Rectal Administration

Rectal drug delivery is an effective alternative to oral and parenteral treatments. This route allows for both local and systemic drug therapy. Traditional rectal dosage formulations have historically been used for localised treatments, including laxatives, hemorrhoid therapy and antipyretics. However, this form of drug dosage often feels alien and uncomfortable to a patient, encouraging refusal. The limitations of conventional solid suppositories can be overcome by creating a thermosensitive liquid suppository. Unfortunately, there are currently only a few studies describing their use in therapy. However, recent trends indicate an increase in the development of this modern therapeutic system. This review introduces a novel rectal drug delivery system with the goal of summarising recent developments in thermosensitive liquid suppositories for analgesic, anticancer, antiemetic, antihypertensive, psychiatric, antiallergic, anaesthetic, antimalarial drugs and insulin. The report also presents the impact of various types of components and their concentration on the properties of this rectal dosage form. Further research into such formulations is certainly needed in order to meet the high demand for modern, efficient rectal gelling systems. Continued research and development in this field would undoubtedly further reveal the hidden potential of rectal drug delivery systems.

Development of the suppository form of human immunoglobulin preparation with high titers of antibodies to herpes simplex virus types 1 and 2 for the treatment of chronic forms of herpetic disease

In spite of the vast arsenal of therapeutic agents, therapy of herpes virus infection (HVI) is very difficult, particularly in pregnant women, newborns and children in the first years of life, as well as in patients with immune deficiency. In this regard, possibility of using immunoglobulins for the treatment of HVI is currently attracting the attention of doctors. The aim of this work was to develop a suppository form of the drug containing donor immunoglobulins with high levels of neutralizing antibodies to herpes simplex virus types 1 and 2 for the treatment of chronic forms of herpetic disease. The study included the following steps: 1) selection of gamma-globulins with high antibody titer for HSV-1 and HSV-2 ELISA test; 2) determination of the level of neutralizing antibodies in the selected series of gamma-globulins in tests in tissue cultures and animals; 3) lyophilization of immunoglobulins; 4) development of the suppository form of the preparation containing gamma-globulin donors with high levels of neutralizing antibodies to HSV-1 and HSV-2; 5) study of the safety of the activity of neutralizing antibodies to HSV-1 and HSV-2 in the suppository form of the drug with hyaluronic acid used as immunomodulator. As the result of this work, immunoglobulin preparation in the suppository form was developed. The developed preparation meets the requirements for safety and efficacy. It is not toxic or pyrogenic. The problems of clinical use of this drug as a method of HVI therapy are discussed.

Clinical trial: marine lipid suppositories as laxatives

Cod-liver oil and other marine products containing polyunsaturated fatty acids have anti-inflammatory, anti-bacterial and anti-viral effects and may be useful in the treatment of various inflammatory and infectious diseases. We developed suppositories and ointment with 30% free fatty acid (FFA) extract from omega-3 fish oil. Our purpose was to evaluate the safety of marine lipid suppositories and ointment in healthy volunteers and to explore the laxative effect of the suppositories. Thirty healthy volunteers were randomized either to a study group administrating 30% FFA suppositories and applying 30% FFA ointment to the perianal region twice per day for two weeks, or to a control group using placebo suppositories and ointment in a double blinded manner. Results: No serious toxic effects or irritation were observed. In the study group 93% felt the urge to defecate after administration of the suppositories as compared to 37% in the control group (P = 0.001). Subsequently 90% in the study group defecated, compared to 33% in the control group (P = 0.001). Conclusion: The marine lipid suppositories and ointment were well tolerated with no significant toxic side effects observed during the study period. The suppositories have a distinct laxative effect and we aim to explore this effect in further clinical trials.

Solid dispersion in pharmaceutical technology. Part II. The methods of analysis of solid dispersions and examples of their application

In the first part of the article solid dispersions were classified the properties and methods of their preparation were described. This section presents methods of analysis of solid dispersions i.e.: thermoanalytical methods, XRPD, FTIR, microscopic methods, dissolution studies and examples of drug forms where solid dispersions were used.

Effects of surfactant characteristics on drug availability from suppositories

The addition of surfactants to suppository formulations is referred to in the scientific literature, but their effects on drug availability remain uncertain. Surfactants are reported to improve drug dispersion into hard fatty excipients, to increase the spreading of the melted suppository on the rectal mucosa leading to a greater contact surface, to reduce the viscosity of the molten mass and to reduce the pathway of drug particles to the interface. In the present study a systematic investigation based on tensiometric and rheological methods was carried out to evaluate the effects of nonionic surfactants with different HLBs (hydrophilic-lipophilic-balance) on drug availability and to clarify the possible mechanisms involved in the release process. The relationship between the melted suppositories and a membrane simulating the rectal barrier were investigated in the course of the in vitro release test by measuring their energy characteristics. At the same time, the potential influences of such interactions on drug release were investigated in suppositories formulated with different kinds and concentrations of surfactant additives. Drug availability was influenced not only by the interaction between the suppository and the rectal membrane but also by the interaction between surfactant, lipophilic excipient and suspended drug particles. Such interactions appear to greatly influence drug release from suppositories, which, in turn, is the main parameter determining drug availability.

[Technology of vitamins containing double layer suppositories]

At present ascorbic acid and cyanocobalamin are widely used in medical practice. Often they are administered simultaneously; chemically they are incompatible, as ascorbic acid (redox compound) inactivates cyanocobalamin. The combination of ascorbic acid and cyanocobalamin is the problem of pharmacy. To solve the problem double-layer suppositories containing two incompatible vitamins: ascorbic acid and cyanocobalamin were developed. Pharmaceutical bioavailability of ascorbic acid and cyanocobalamin has been studied using in-vitro methods to develop optimal base for suppositories. As a result of investigations optimal composition and technology of the double-layer suppositories containing ascorbic acid and cyanocobalamin which met requirements has been developed. Sequential release of active compounds and as a result - sequential pharmacologic action is achieved.

[Biopharmaceutic and technological investigation of vagina suppositories containing brilliant green]

The vaginal suppository composition, containing 0, 05, 0, 1 and 0, 5 of drug substance is presented. The release of drug substance was investigated. The influence of a number of the factors on the degree of release was investigated. Cocoa oil, confectionery fat and three different types of emulgator were used. According to gained results the average release degree was 73-76%, which is sufficient for effective action of a preparation. The technological parameters of suppositories including the temperature melting and hardening are determined. All parameters were at an acceptable level. The optimum composition of suppositories was determined. The optimal composition of suppositories was determined (base, emulgator, the content of active substance, mass of the suppository. The investigation proved the effectiveness of the preparation.

Formulation and Characterization of Poly(ethylene Glycol)-Based, 5-Aminolevulinic Acid-Loaded Solid-Dosage Forms Intended for Photodynamic and Photodiagnostic Methodologies in the Colorectal Region

Aminolevulinic acid-loaded, poly(ethylene glycol) disks prepared using three molecular weights (1000, 6000, and 10,000) were shown to be of potential for rectal administration as part of photodynamic and photodiagnostic colorectal procedures. The disk-shaped delivery system was mechanically robust, as judged by friability measurements. Calorimetric analysis confirmed that low concentrations of ALA (1% w/w) were dispersed completely throughout the PEG matrix, but higher concentrations (5% w/w and 10% w/w) formed crystalline suspensions. The molecular weight of the PEG determined the melting temperature, with PEG 1000 being suitable for melting around body temperature. The drug release kinetics were shown to be a function of both molecular weight and drug loading. Although the higher molecular weight PEG disks were resistant to surface erosion arising from an aqueous receptor phase, this effect was counterbalanced by more rapid and complete release when the ALA loading was increased. The lowest loading used (1% w/w) produced incomplete release, often not exceeding 30% of the total amount of drug. Results suggest that this simple formulation containing ALA can be administered directly to the colorectal area and is a feasible alternative to peroral dosing of ALA.

Comparative Drug Release Measurements in Limited Amounts of Liquid: A Suppository Formulation Study

A novel method for the investigation of drug formulations in limited liquid volumes is presented. The experimental setup consists of a measurement cell containing an absorbent sponge cloth placed between two parallel electrodes. Conductivity measurements are used to monitor the drug release from the dosage form. By varying the amount of water contained in the absorbent cloth surrounding the dosage form, it is possible to measure the drug release performance of the dosage form in very limited amounts of water. The method was employed to test four different tablet formulations consisting of the model drug NaCl incorporated in excipient matrices of hard fat, polyethylene glycol, microcrystalline cellulose and a mixture of microcrystalline cellulose and croscarmellose sodium (Ac-Di-Sol). The drug release rates of the different formulations in limited water volumes differed markedly from the release rates in an excess of water. Whereas the release rates from all tablet types in an excess of water showed only minor differences among the tablet types, the release rates from the tablets formulated with disintegrating excipients were clearly superior in limited water volumes. The developed method for drug release in limited volumes of liquid should be suitable for evaluation of rectal dosage forms.

Evaluation of Mucin as a Release Enhancer for Rectal Delivery of Glibenclamide

In this work mucin was evaluated as a release and absorption enhancer for glibenclamide from rectal glycerogelatin suppository. Glycerogelatin suppositories containing different ratios of glibenclamide to I-mucin (insoluble), S-mucin (soluble) and sodium salicylate respectively, were formulated using the fusion method. The suppositories were evaluated using standard parameters. Release studies were carried out in phosphate buffer (pH 7.6). The pharmacodynamic (PD) evaluation of the formulations was carried out on normoglycaemic albino rats. The results of the physical tests showed that the suppositories possessed high resistance to rupture and had uniformity of weight and drug contents. The erosion times of the suppositories with I-mucin, S-mucin and sodium salicylate were shorter than glycerogelatin suppositories BP without any release enhancer (control). Analysis of the release data showed that the release pattern was bi-phasic with initial fast release and subsequent slow release of the glibenclamide from the suppositories. The release mechanism followed first order kinetics. All the suppositories containing either S-mucin, I-mucin or sodium salicylate showed better glibenclamide release than the control without any release enhancer (p < 0.05). The pharmacodynamic studies showed that the overall glucose lowering effect in rats was greater in S-mucin suppositories than in sodium salicylate and I-mucin suppositories. The results of this study indicated that mucin extracted from Bovine spp. could be used to enhance the release and subsequent absorption of glibenclamide from rectal glycerolgelatin suppositories.

Population pharmacokinetic investigation of phenobarbital by mixed effect modelling using routine clinical pharmacokinetic data in Japanese neonates and infants

The population pharmacokinetics of phenobarbital was evaluated using 69 serum concentration measurements obtained from the routine phenobarbital monitoring of 35 neonates and infants. The data were analysed using the nonlinear mixed effects model. A one-compartment open pharmacokinetic model with first-order elimination was used. Covariates screened were current bodyweight (TBW), gestational age, postnatal age (PNA), postconceptional age and gender. The final pharmacokinetic parameters were CL/F (mL/h) = 3.41.TBW (kg) + 1.64. PNA (weeks), Vd/F(L) = 1.09.TBW.(kg) [corrected] and F = 0.406 for oral administration and F = 1 for suppository. Application of the findings in this study to patient care may permit selection of an appropriate initial maintenance dosage to achieve target phenobarbital concentrations, thus enabling the clinician to achieve the desired therapeutic effect in neonates and infants.

In vitro methods for the evaluation of drug availability from suppositories: comparison between biological and artificial membranes

Drug availability from suppositories is currently evaluated in vitro by means of a model consisting of a dialysis tube (porous membrane) or isolated biological membrane (animal rectum). We propose a new alternative in vitro method to determine drug availability from suppositories consisting of an artificial membrane soaked with n-octanol, coupled with a filter paper sheet soaked with phosphate buffer. This method provides for an integrated hydro-lipophilic simulation of the biological membrane, including the mucus layer adhering to the rectal mucosa. By simply using the porous membrane, the amount of drug released varied directly according to its solubility for formulations with lipophilic excipients. For formulations with hydrophilic excipients, drugs with low/intermediate solubility in water showed increased availability in comparison to lipophilic excipients. The in vitro rat rectum model provided overall results that were similar to those obtained with the porous membrane method, although the percentage values of AUC were lower. The new model of in vitro simulated absorption produced a degree of drug availability that was lower in comparison to both previous methods. However, the simulated model appeared to give a pattern of drug availability closer to that of the model of in vitro rat rectum. The new in vitro artificial model thus appears to be useful in suppositories preformulation studies, allowing for an estimate of drug availability and the choice of the most adequate excipient.

Validation of liquid chromatographic method for analysis of lidocaine hydrochloride, dexamethasone acetate, calcium dobesilate, buthylhydroxyanisol and degradation product hydroquinone in suppositories and ointment

In this paper, there was developed a sensitive, precise and accurate reversed-phase liquid chromatographic (RP-HPLC) method and validated for simultaneous determination of lidocaine hydrochloride, dexamethasone acetate (DA) and calcium dobesilate (CD) in suppositories and ointment. Also there was achieved a parallel analysis of buthylhydroxyanisol, as a preservative, and hydroquinone, as a degradation product of calcium dobesilate, present in these dosage forms. The relative standard deviation (RSD) values for all five compounds indicated a good precision and accuracy of the RP-HPLC method. Method is selective, sensitive and reproducible with good recovery values and can be applied in simultaneous determination of all mentioned compounds.

Focused microwave-assisted extraction and LC determination of the active ingredient in naproxen-based suppositories

A simple and rapid open-vessel focused microwave-assisted extraction (FMAE) method followed by LC analysis was developed for the determination of naproxen in suppositories. Parameters which might affect the FMAE method, such as nature and volume of the extraction solvent, temperature and extraction time were optimized. The extraction solvent consisted of methanol/sodium hydrogen carbonate (pH 8.7; 0.1 M) (50:50, v/v). Extractions were performed by reaching the target temperature of 70 degrees C in a 7 min linear ramp and then maintaining the target temperature for 3 min. Chromatographic analysis was performed on a Discovery RP-Amide C16 column (250 mm x 4.6 mm i.d., 5 microm particle size). The mobile phase consisted of acetonitrile/potassium dihydrogenphosphate (pH 3.0; 25 mM) (40:60, v/v). The complete analytical procedure was validated with regard to limit of quantification, linearity, precision and accuracy. The advantages of the proposed method in comparison to conventional methods are decreased extraction time, reduced solvent consumption and no further sample clean-up steps required before liquid chromatographic analysis.

Development of suppository formulation safely improving rectal absorption of rebamipide, a poorly absorbable drug, by utilizing sodium laurate and taurine

To develop the safe formulation that can safely improve bioavailability of poorly absorbable drugs and that is practically available, we prepared the suppositories of rebamipide, a poorly soluble and poorly absorbable antiulcer drug, by employing the combinatorial use of sodium laurate (C12), an absorption enhancer, with taurine (Tau) or L-glutamine (L-Gln), an adjuvant exerting the cytoprotective action. Although the dissolution of rebamipide from fatty base (FB) suppository prepared using Witepsol H-15 was very slow, it was remarkably improved by the addition of C12 and L-Gln or Tau into the suppository. On the other hand, the dissolution of rebamipide from water-soluble base (WB) suppository prepared using polyethylene glycol was very rapid and the addition of adjuvants did not influence its dissolution so much. Rectal absorption of rebamipide examined in rats was remarkably improved by FB suppository containing C12 or both C12 and Tau, while the enhancing effect of C12 was relatively small in the case of WB suppositories. Biochemical and histopathological studies have confirmed that FB suppository containing both C12 and Tau or L-Gln did not cause any serious local damage, while FB suppository containing C12 only caused the erosion and shrinkage for a lot of rectal epithelial cells. In conclusion, FB suppository employing the combinatorial use of C12 with Tau could be a promising formulation that is effective and safe enough for poorly absorbable drugs to be practically administered.

Evaluation of sustained release suppositories prepared with fatty base including solid fats with high melting points

To prepare the sustained release suppositories, solid fats such as polyglycerol ester of fatty acids (PGEFs) or beeswax were utilized with a fatty suppository base, Witepsol H15. PGEFs such as decaglycerol heptabehenate (HB750) and hexaglycerol pentastearate (PS500), and beeswax have relatively high melting points. The addition of PGEFs or beeswax to Witepsol H15 increased the apparent viscosity of suppository bases at 37 degrees C without any large change in the melting point of Witepsol H15. Moreover, the apparent viscosity of a mixed base with HB750, PS500 or beeswax at 37 degrees C was significantly correlated with the amount of each solid fat in a mixed base. The release of acetaminophen (AAP), a model drug, from suppositories was delayed by HB750, PS500 or beeswax, and an excellent correlation was observed between the apparent viscosity of these mixed bases and Higuchi's rate constants in each mixed base suppository, suggesting that these solid fats could regulate the drug release from the mixed base suppositories by changing their viscosity. In the in vivo absorption study in rats, several suppositories made from Witepsol H15-HB750 or Witepsol H15-beeswax mixed bases prolonged the rectal absorption of AAP without reducing AUC. In conclusion, by using solid fats such as HB750 and beeswax with relatively high melting points, it is possible to control the rate of drug release from fatty base suppositories for maintaining the plasma concentration of drugs for longer time periods.

Investigation of Product Quality Between Extemporaneously Compounded Progesterone Vaginal Suppositories and an Approved Progesterone Vaginal Gel

The purpose of this investigation was to compare quality parameters, including product appearance, content uniformity, pH, weight uniformity, microbial limit testing and preservative effectiveness testing on extemporaneously compounded progesterone vaginal suppositories obtained from 10 randomly chosen compounding pharmacies (90 suppositories each) across the United States, to the Food and Drug Administration (FDA) approved prescription progesterone gel product (Prochieve/Crinone) which is manufactured in a cGMP regulated facility. The content uniformity and pH were determined using qualified methods. The microbial limits testing and preservative effectiveness testing were conducted according to compendial methods. Only one pharmacy provided suppositories that were all within the potency limits required for the prescription progesterone gel product. The other pharmacies provided at least some suppositories where progesterone content was either subpotent or superpotent for progesterone. The pH of most of the compounded suppository products was in the range of 4.22 to 7.68 with a median of 6.30 (normal vaginal pH is <5), whereas the gel product was 2.80. For compounded product from one of the pharmacies, microbial limits testing indicated CDC group IVC-2 and Comamonas acidovorans were detected. This data indicates that pharmacy compounded delivery systems for progesterone should be used with caution.

Salbutamol sulfate suppositories: influence of formulation on physical parameters and stability

PURPOSE

To prepare and evaluate a suppository dosage form of salbutamol sulfate. The prepared formulae with and without different concentrations of gels were tested for hardness, melting time, content uniformity, and drug release. The stability of some of the selected formulae was assessed.

METHODS

Salbutamol sulfate was formulated as a rectal suppository with emulsifying fatty bases (suppocire and witepsol) and water-soluble bases (PEG) adopting the molding from a melt technique. Physical characteristics and dissolution profiles of the prepared formulations were determined as the responses. The effects of adding gels, methyl cellulose (MC), and Eudispert (Eud) and their concentrations (1, 3, and 6%) on these responses were also investigated. Formulations showing high rank order were scaled up for shelf-life stability study for one year.

RESULTS

The results showed that all the investigated formulae have acceptable physical characteristics with respect to hardness, melting time (except F7), and uniformity of drug content. The amount of drug dissolved in 100 min of dissolution time was inversely affected by the melting point of the fatty base. The release from PEG bases was found to be molecular weight dependent. Addition of 1% MC or Eud gel increased the release from all the investigated formulae. Increasing gel concentration to 3% then to 6% showed different effects on the release. The degradation of salbutamol sulfate in the investigated formulae was found to be a first-order reaction.

CONCLUSIONS

Rectal suppository of salbutamol sulfate could be prepared as an alternative to the oral dosage form to circumvent the first-pass metabolism.

[Study on preparation procedure of Suppositoria Radix Bupleuri for kids]

OBJECTIVE

To optimize the preparation procedure of Suppositoria Radix Bupleuri for Kids.

METHODS

The extraction process and preparation procedure were studied by orthogonal experimental design.

RESULTS

The extraction process was selected and suppositoria was prepared by hard fat.

CONCLUSION

This preparation procedure is suitable.

Thermal and rheological study of lipophilic ethosuximide suppositories

We have performed thermal (differential scanning calorimetry) and rheological studies in the preformulation phase of ethosuximide suppositories to determine the influence of the active ingredient and adjuvants on the melting characteristics and rheological performance of the suppositories. Both types of studies were performed on the fatty bases witepsol H-19 and suppocire AP, each mixed with 5% w/w polysorbate 80, 0.1% w/w docusate sodium and 3% w/w tetranyl AT-1/DP and on the suppository formulations obtained by the addition of 150 mg of ethosuximide to these excipients. Pure lipophilic excipients have two peaks in the DSC curve. The first one occurs at lower temperatures (27.35 degrees C for the suppocire AP and 34.3 degrees C for the witepsol H19) and the second peak at higher temperatures (36.27 and 35.95 degrees C for the suppocire AP and witepsol H19, respectively). Polysorbate 80, docusate sodium and tetranyl AT-1/DP cause the first melting peak to disappear and the second peak to occur at a lower temperature. The thermograms of the formulas show two melting peaks and the endothermic peak does not appear due to the melting of ethosuximide (47.8 degrees C). We attribute this behavior to the solubility of the drug in the melted excipient, thus originating a decrease of the melting temperature of the second peak in the DSC scan. The excipients and formulations behave as Newtonian fluids and the influence of ethosuximide and adjuvants can be noted in an increase in the viscosity of the suppository mass.

Solutol and cremophor products as new additives in suppository formulation

Our research has a double purpose. On the one hand, doctors have expressed the need to formulate a rectal suppository dosage form from diuretic ethacrynic acid, which would add to the choice of treatment methods and thereby increase the possibilities of individual cure. On the other hand, the liberation and thereby the bioavailability of poorly-soluble ethacrynic acid needs to be enhanced, and for this purpose solubility-increasing additives new to rectal therapy were used. Solutol HS 15, Cremophor RH 40, and Cremophor RH 60 were used as additives in concentrations of 1, 3, 5, and 10%. The quantity of drug released changed as a function of additive concentration. Depending on the acceptor phase, the best results were achieved with an additive concentration of 1-3%, which is related to the optimal additive quantity accumulated on the boundary surface.

Investigation of physical and hypoglycaemic properties of rectal suppositories with chosen insulin

Rectal suppositories with insulin Humulin M3 (30/70) were prepared. Witepsol H15 and a polyoxyethyleneglycol mixture, composed of PEG 400, PEG 1000 and PEG 6000, were used as bases. Tween 60 and sodium salicylate were used as auxiliary substances. Hypoglycaemic properties of the prepared suppositories were tested on rabbits. The obtained results were compared with the data acquired after intravenous administration of insulin and subcutaneous injection of insulin.

Effect of sodium chloride on the gelation temperature, gel strength and bioadhesive force of poloxamer gels containing diclofenac sodium

Liquid suppository systems composed of poloxamers and bioadhesive polymers were easy to administer to the anus and mucoadhesive to the rectal tissues without leakage after the dose. However, a liquid suppository system containing diclofenac sodium could not be developed using bioadhesive polymers, since the drug was precipitated in this preparation. To develop a liquid suppository system using sodium chloride instead of bioadhesive polymers, the physicochemical properties such as gelation temperature, gel strength and bioadhesive force of various formulations composed of diclofenac sodium, poloxamers and sodium chloride were investigated. The mixtures of P 407 (15%) and P 188 (15-20%) existed as a liquid at room temperature, but gelled at physiological temperature. Diclofenac sodium significantly increased the gelation temperature and weakened the gel strength and bioadhesive force, while sodium chloride did the opposite. Furthermore, the poloxamer gels with less than 1.0% of sodium chloride, in which the drug was not precipitated, were inserted into the rectum of rabbits without difficulty and leakage, and retained in the rectum of rats for at least 6 h. Our results suggested that a thermosensitive liquid suppository system with sodium chloride and poloxamers was a more physically stable and convenient rectal dosage form for diclofenac sodium.

Evaluation of an acetic acid ester of monoglyceride as a suppository base with unique properties

The objective of this investigation was to evaluate an acetic acid ester of monoglycerides made from edible, fully hydrogenated palm oil (AC-70) as a suppository base and compare it with a commercially available semisynthetic base (Suppocire AI). Benzocaine and miconazole were used as model drugs. Suppositories were prepared by the fusion method. The drug loads in the suppositories were kept at 2% to 5% (wt/wt). In vitro release of drug from the suppositories into Sorensen's phosphate buffer (pH 7.4) was studied using a US Pharmacopeia dissolution apparatus 1 and a spectrophotometer. The melting behavior of the bases and the physical state of the drug in the suppositories were studied using a differential scanning calorimeter (DSC). Powder x-ray diffractometry was used to study any possible polymorphic changes in the AC-70 base during formulation and storage. In vitro release studies revealed that the release of benzocaine from the AC-70 suppository was substantially slower than that of the commercial AI base. At a 2.5% (wt/wt) benzocaine load, the release of drug from the AC-70 suppositories was found to be linear. This slow and linear release was attributed to the physical property of the base, which forms liquid crystalline phases in the aqueous dissolution medium. The lyotropic liquid crystalline phase has the ability to incorporate drug into its structure and can control the release kinetics of the drug from such a system. The apparent pH of the release medium (water) was decreased by 1 to 1.5 pH units when the AC-70 base was used. The DSC studies revealed that the melting range of the AC-70 base is 36 degrees C to 38 degrees C, which is ideal for suppository formulations. The results of these studies support the possibility of using this new base for slow-release suppository formulations. This base may be of particular interest for a drug that requires an acidic environment to maintain its activity.

[Diagnostic image (11). (Urine sample with fat droplets)]

In a urine sample of a 44-year-old female patient suppository base was found due to a wrong insertion of a diclofenac suppository.

Determination of fluocortolone pivalate and fluocortolone hexanoate in suppositories using reverse-phase HPLC

Fluocortolone and its esters are synthetic corticosteroids used topically in the treatment of various skin disorders. A method that can be successfully used for the separation and determination of fluocortolone pivalate and fluocortolone hexanoate in suppositories was developed. This method is based on reverse-phase HPLC on Supelcosil LC-18 (25 cm x 4.6 mm, 5 microns), using methanol-acetonitrile-water-glacial acetic acid (17:46:37:0.4 v/v/v/v) as mobile phase at a flow rate of 3.0 ml/min. Detection was carried out using a UV detector at 238 nm. The method developed was validated, and calibration curves were established dependent on peak area. The validated ranges for fluocortolone pivalate and fluocortolone hexanoate are 15-305 micrograms/ml (r = 0.9995) and 15-315 micrograms/ml (r = 0.9996), respectively. The limits of detection and the limits of quantification for both esters were also determined.

Effect of additives on the physicochemical properties of liquid suppository bases

To investigate the effects of additives on the physicochemical properties of in situ gelling and mucoadhesive liquid suppository base, gelation temperature, gel strength and bioadhesive force of liquid suppository base, poloxamer 407 (P 407) and poloxamer 188 (P 188) (15/15%) were evaluated in the presence of following additives: solvent (ethanol, propylene glycol, glycerin), ionic strength-controlling agent (sodium chloride) and pH-controlling agent (hydrochloric acid, sodium monohydrogen phosphate, sodium dihydrogen phosphate). Among the additives studied, sodium chloride, sodium monohydrogen phosphate and sodium dihydrogen phosphate increased to a great extent the gel strength and the bioadhesive force of P 407/P 188 (15/15%) with a decrease in gelation temperature. Glycerin slightly decreased the gelation temperature and slightly increased the gel strength and bioadhesive force. However, the addition of 1% of sodium chloride, sodium monohydrogen phosphate or sodium dihydrogen phosphate caused a greater than 60-fold increase in gel strength and over a tenfold increase in bioadhesive force with 2-4 degrees C decrease of gelation temperature within optimal range, compared with P 407/P 188 (15/15%) alone. On the other hand, ethanol, propylene glycol and hydrochloric acid increased the gelation temperature and slightly decreased the gel strength and the bioadhesive force. Taken together, these findings indicate that the effect of additives on the physicochemical properties of liquid suppository bases depends on their bonding capacities, in that additives such as sodium chloride, sodium monohydrogen phosphate and sodium dihydrogen phosphate having strong cross-linking bonds with the components of liquid suppository base increase the strength and bioadhesive force of a gel compared to liquid suppository base alone, while additives such as ethanol, propylene glycol and hydrochloric acid having weaker hydrogen bonding result in a weaker response. Thus, sodium chloride and sodium phosphates appear to be promising additives for in situ gelling and mucoadhesive liquid suppository base, if used in adequate amounts.

Development of a rectal nicotine delivery system for the treatment of ulcerative colitis

The aims of this investigation were: i. to develop a rectal nicotine delivery system with bioadhesives for the treatment of ulcerative colitis and ii. to evaluate nicotine transport and cytotoxicity of the delivery system using Caco-2 cell culture systems. Rectal nicotine suppository formulations were prepared in semi-synthetic glyceride bases (Suppocire AM and AI, Gattefosse Inc.) by fusion method. The in vitro release of nicotine was carried out in modified USP dissolution apparatus 1. Differential scanning calorimetry (DSC) and powder X-ray diffraction were used to study the polymorphic changes if any in the formulations. An LC method was used for the assay of nicotine. The effect of bioadhesives (glyceryl monooleate (GMO), and Carbopol) on the nicotine flux was evaluated using Caco-2 cell permeability studies and Caco-2 cell viability was determined using the MTT toxicity assay. In vitro release studies indicated that the low melting AI base was superior to that of the AM base. Presence of GMO in the formulation enhanced the release of nicotine whereas Carbopol showed an opposite effect. The enhanced release of nicotine in the presence of GMO was found to be partly due to the melting point lowering effect of this compound. Caco-2 cell absorption studies showed that there was a decrease in the flux of nicotine in the presence of both the bioadhesives. The flux of the fluorescein marker which is used to study the integrity of the cell monolayers was found to be slightly higher only in the presence of 10% (w/w) Carbopol. Nicotine, Carbopol, and GMO do not have any cytotoxic effect on these cell monolayers within the concentration range used in the formulations. Rectal nicotine formulations containing bioadhesives were developed and characterized. Both in vitro release and cell culture studies have indicated that one can manipulate the nicotine release from these rectal delivery systems by incorporation of various bioadhesives or the use of different bases in the formulation. Nicotine concentration below 2% (w/v) and bioadhesive concentration below 10% (w/w) do not have any cytotoxic effect on Caco-2 cells.

Percolation theory, conductivity and dissolution of hydrophilic suppository bases (PEG systems)

We investigated the conductivity of binary mixtures of different volume to volume ratios of liquid polyethylene glycol 200 (PEG 200) and solid PEG 6000. The conductivity was measured using a specially designed cell, which could be filled with the sample to be analysed. The results were analysed by the help of the percolation theory and its basic equation: X=S(p-p(c))(q) with X=gamma the conductivity and X=k the dissolution rate constant of binary mixtures with p the concentration of PEG 200 including Mepyraminmaleat as a marker substance. The intrinsic dissolution rate was determined spectrophotometrically. The simultaneous determination of the critical exponent q and the percolation threshold p(c) of the conductivity experiment yielded the following values q=1.83+/-0.05 and p(c)=11.6+/-1.1% with a squared correlation coefficient R(2)=0. 9986. For q=mu=2.00 fixed the percolation threshold is equal to p(c)=8.4+/-1.3% with R(2)=0.9984. Thus if the same percolation threshold p(c)=8.4+/-1.3% is adopted for the dependence of the dissolution process q becomes equal to q approximately mu=1. 94+/-0.045. R(2)=0.9991. This result is in excellent agreement with the theoretical prediction that the permeability of a porous network scales in the same way as the conductivity.

Influence of neutron activation factors on the physico-chemical properties of suppositories and their excipients

The effect of the neutron activation factors, i.e., admixture of samarium oxide (Sm2O3) and irradiation time, on the physico-chemical properties of the raw materials and the in vitro dissolution and disintegration of hydrophilic and lipophilic suppositories was investigated. It was possible to expose the pure bases and the model drugs (5-aminosalicylic acid [5-ASA] and ropivacaine hydrochloride) to 1 min of neutron irradiation in a flux of 1.1.1013 n cm-2s-1. The dissolution and disintegration of the corresponding suppositories showed that the physico-chemical properties and the fraction of incorporated drug together with the lipophilic/hydrophilic nature of the base were important factors. Sm2O3 increased the disintegration time of hydrophilic suppositories containing 5-ASA, while the dissolution of both drugs from these formulations remained unchanged. Sm2O3 did not alter the disintegration time of the lipophilic formulations, but it reduced the dissolution of both drugs from these suppositories. Irradiation induced different behaviour in the different bases.

Determination of tramadol in various dosage forms by capillary isotachophoresis

Cationic capillary isotachophoresis (ITP) with conductometric detection has been used for separating and determining milligram amounts of tramadol [2-dimethylaminomethyl-1-(3-methoxyphenyl)-cyclohexanol hydrochloride] (I) in seven commercial mass-produced pharmaceutical preparations. The optimised ITP electrolyte system consisted of 5 mM potassium picolinate + 5 mM picolinic acid (pH 5.25) as the leading electrolyte and 10 mM formic acid as the terminating electrolyte. The driving and detection currents were 50 microA (for 320 s) and 10 microA, respectively (a single analysis took 12-15 min). Under such conditions the effective mobility of I was determined as 24.26 x 10(-9) m2 V(-1) s(-1) (with tetraethylammonium ion as standard); thermodynamic pKa value of I was 9.44 +/- 0.03 (n = 8) as determined by UV spectrophotometry at 25 degrees C and I = 0.01 (NaCl). The calibration graph relating the ITP zone length to the concentration of I was rectilinear (r = 0.99997) in the range 15-180 mg l(-1) of I. The relative standard deviation (RSD) was 0.21% (n = 6) when determining 60 mg l(-1) of I in pure test solution. Sample pre-treatment of the dosage forms involved dilution or extraction of I with water (for suppositories the extraction was carried out in an ultrasonic bath at 40 degrees C for 10 min). The method was suitable for determining 50 or 100 mg ml(-1) of I in injections and drops, 50 mg of I in capsules, and 100 mg of I in suppositories with RSD values 0.4 to 1% (n = 6). According to the validation procedure based on the standard addition technique the recoveries were 97.2-100.1% of I.

Capillary electrophoresis for the analysis of tropane alkaloids: pharmaceutical and phytochemical applications

Three capillary electrophoresis methods, using UV detection, were developed for the simultaneous determination of several tropane alkaloids, including atropine, scopolamine and synthetic derivatives. After optimization, the validated capillary zone electrophoresis methods were applied to the determination of these compounds in various pharmaceutical forms, such as ophthalmic and injection solutions, tablets, suppositories and aerosols. Capillary electrophoresis in the micellar mode was found to be more appropriate for the analysis of hyoscyamine and scopolamine in plant material. These two compounds are generally found together with other tropane alkaloids which present similar structures and charge to mass ratio. Furthermore, the separation of positional isomers, such as hyoscyamine and littorine generally encountered in plant extracts, was also considered. The developed method was applied to the analysis of hairy root extracts of Datura candida x Datura aurea, Datura quercifolia and Hyoscyamus albus.

Inverse supercritical extraction of acetaminophen from suppositories

The use of supercritical CO2 for the isolation of acetaminophen from the non-polar matrix of a suppository is demonstrated. Since acetaminophen is not soluble in pure CO2 at low pressure, but the waxy matrix is, the later can be extracted, leaving the acetaminophen behind. After studies on acetaminophen solubility as a function of pressure, temperature flow and supercritical fluid volume, optimal extraction conditions were determined. In this method, the matrix is removed using pure CO2 at 1500 psi and 40 degrees C, and the remaining acetaminophen is then removed from the extraction cell using ultrasound in warm water. This method is an alternative to the US Pharmacopoeia's (USP) method for this kind of formulation, which involves the dissolution of the matrix in hexane with the subsequent liquid-liquid extraction of the acetaminophen into water.

Secondary pharmaceuticals manufacturing

Drs. Burling and Shah examine the second part of the pharmaceuticals manufacturing process, in which formulations for drug delivery are determined. Several types of formulations and their potentials for occupational exposure are reviewed.

Preparation, characterization, and pharmaceutical application of linear dextrins. III. Drug release from fatty suppository bases containing amylodextrin

Drug release from fatty suppository bases containing a solid dispersion of diazepam with amylodextrin or a complex of prednisolone with amylodextrin was analyzed in a flow-through model. Being present as a suspension in the fatty base, particles of complex or solid dispersion are transported to the lipid-water interface by sedimentation. After entering the aqueous phase they partially dissolve. The suppositories showed increased drug release compared with the corresponding suppositories containing drug only. Because of the partial solubility of amylodextrin, drug release was lower than the release from drug-cyclodextrin complexes. Use of the soluble fraction of amylodextrin for both the solid dispersion and the complex further enhanced drug release, but it was still below that of drug-cyclodextrin complexes.

Methods of evaluation of release of carbon dioxide from effervescent suppositories

Two different test methods were studied for the evaluation of release profiles of carbon dioxide, CO2, from effervescent suppositories. Three lots of commercial suppositories containing sodium bicarbonate and anhydrous sodium dihydrogen phosphate were used. The volume of CO2 released from these suppositories in normal saline with or without polysorbate 80 as a medium was measured with a gas burette. In the measurement performed using the apparatus without stirring, method 1, only 60% of CO2 was released from the suppositories in the medium without polysorbate 80. In this measurement, a native release profile was detected because the medium was not stirred. In the case with stirring, however, method 2, 100% was released from those suppositories in the medium containing 1% polysorbate 80 with comparatively low standard deviations. These findings indicate that method 1 is most beneficial for a test comparing the effects of various factors such as additives and melting points on the release profiles of CO2 from the effervescent suppositories. However, this method is not practical for quality control of formulations because of the incomplete release of CO2; method 2, in contrast, is useful because of its complete release and low standard deviations. These results suggest that methods 1 and 2 for release tests of CO2 are most applicable to the early and late formulation studies of effervescent suppositories, respectively.

Effects of bases and additives on release of carbon dioxide from effervescent suppositories

For the formulation of effervescent containing sodium bicarbonate and anhydrous sodium dihydrogen phosphate, the effects of bases and additives on the release profile of carbon dioxide, CO2, from the suppositories were studied by an in vitro release test using a gas burette. The suppository bases employed were Witepsol H-15, W-35 and E-85, and the additives were Aerosil 200 and soybean lecithin. The melting points and viscosities of the suppositories were also measured to interpret the CO2 release profiles. The rate and amount of CO2 released from suppositories prepared with bases having different melting points and hydroxyl values decreased with increasing melting point and decreasing hydroxyl value. The addition of Aerosil 200 to the suppository bases considerably reduced the rate and amount of CO2 released owing to the increasing viscosity of the melted bases, while the addition of soybean lecithin to those bases increased the rate and amount of CO2 released because of the improved wettability. Thus, the release profiles of CO2 from the effervescent suppositories were considerably influenced by the hydroxyl values related to the contents of mono- and di-glycerides, the melting points of the bases, Aerosil 200 and soybean lecithin. This suggests that the rate and amount of CO2 released from the suppositories can be freely controlled by the combination of these various factors.

Allergy to lysozyme/egg white-containing vaginal suppositories

Seven patients who received a lysozyme, nystatin, and tetracycline containing vaginal suppository because of suspected vaginal infection, developed local or systemic allergic reactions. The coincidence of the symptoms with the repeated use of the suppository as well as skin and lymphocyte transformation tests indicated that the lysozyme in the suppository was responsible for the allergic reactions. This lysozyme preparation contained additional egg proteins, which contributed to the allergic reaction in certain patients: three patients with a previous history of egg allergy and serologic and/or skin test evidence for egg-white sensitization developed the allergic reaction after the first suppository. Four patients had urticaria or anaphylaxis after treatment for at least three days; none of these four patients developed egg allergy. Five of seven individuals had positive skin tests (prick or scratch) to ovomucoid and lysozyme, but none of the patients had lysozyme-specific IgE in the circulation. All seven patients, with or without egg allergy, showed vigorous T cell responses to purified lysozyme and partly to other egg-white proteins in the lymphocyte transformation test, which was absent in controls. Vaginal suppositories that contain lysozyme and other contaminating egg white proteins can either elicit allergic reactions in patients with a preexisting egg white allergy or induce sensitization to lysozyme and other egg white components.

[Formulation and analysis of suppositories containing papaverine hydrochloride. Part 2. In vitro membrane diffusion studies]

Rectal suppositories with 0.10 g/2.0 g Papaverine hydrochloride content were made with 12 different vehicles. The membrane diffusion method was used to study the factors influencing the in vitro drug liberation. The Polysorbate 20 and 61 tenside pair, the optimal concentration of which was 5% each, was found to influence diffusion favourably. Neutral oils softening the consistency (Miglyol 812 and Estasan), similarly in 5%, also had a favourable effect on the in vitro diffusion by increasing the spreading properties. As to the lipophil suppository masses with high and low hydroxyl numbers, only the latter could be used favourably. The 6-month-long storage resulted in drug retention in several experimental series. Correlation was found in several cases between the physical parameters of the suppositories and their in vitro drug liberation. Finally, with the help of linear regression calculation and in view of the in vitro relative bioavailability values the optimal vehicle is suggested for the formulation of suppositories containing Papaverine hydrochloride. The triglyceride type Estaram 299 was found to be the most suitable in every respect, either in itself or combined with 5% neutral oil.

[Formulation and analysis of suppositories containing papaverine hydrochloride. Part 1. Choice of the optimal vehicle and determination of the physical parameters of the suppositories]

Suppositories containing 0.10 g papaverine hydrochloride were made with moulding technology to produce spasmolytic effect. The optimal vehicle was tried to be found for these suppositories. During the experiments 12 different suppository masses were used, including lipophil and lipohydrophil vehicles as well as vehicles with low and high hydroxyl numbers. Five different kinds of physical parameters were determined: melting and drop points, disintegration and special penetration times and breaking hardness. The physical parameters of suppositories without active substance and containing papaverine were examined separately. After 6 months of storage the greater part of the masses showed unfavourable changes (after-hardening, increase of the disintegration time, etc.). In the end the Estaram 299 mass, a triglyceride type of mass with a low hydroxyl number was found satisfactory in every respect, either in itself or combined with 5% Estasan neutral oil.