Effect of Characteristics of Compounds on Maintenance of an Amorphous State in Solid Dispersion with Crospovidone

Solid dispersion (SD) of indomethacin with crospovidone (CrosPVP) shows useful characteristics for preparation of dosage forms. This study aimed to determine the types of drugs that could adopt a stable amorphous form in SD. Twenty compounds with various melting points (70-218 degrees C), molecular weights (135-504) and functional groups (amide, amino, carbonyl, hydroxyl, ketone etc.) were prepared in SD with CrosPVP. The CrosPVP SDs were prepared using a mechanical mixing and heating method. Melting point and molecular weight were found to have no influence on the ability of a compound to maintain an amorphous state in SD. All compounds containing hydrogen-bond-donor functional groups existed in an amorphous state in SD for at least 6 months. Infrared spectra suggested an interaction between the functional groups of these compounds and amide carbonyl group of CrosPVP. Compounds without hydrogen-bond-donor groups could not maintain an amorphous state and underwent recrystallization within 1 month. It was suggested that the presence of a hydrogen-bond-donor functional group in a compound is an important factor affecting the stable formation of SD with CrosPVP, which contains a hydrogen-bond acceptor.

Chlorin e6-polyvinylpyrrolidone as a fluorescent marker for fluorescence diagnosis of human bladder cancer implanted on the chick chorioallantoic membrane model

The use of fluorescence diagnosis as a modern cancer diagnostic modality is rapidly gaining importance in the field of urology. It is based on the detection of distinctive light emission of tissues sensitized by fluorescent dyes, commonly referred to as photosensitizers, after irradiation with a specific light source. Therefore, the search for specific fluorescent dyes with high sensitivity and specificity for bladder cancer is constantly being sought after. The aim of this study is to investigate the use of a new formulation consisting a mixture of chlorin e6 and polyvinylpyrrolidone (Ce6-PVP) for the detection of human bladder cancer cells (MGH) implanted on the chick chorioallantoic membrane (CAM) model. Uptake kinetics studies were quantitatively determined for both systemic and topical administrations of Ce6-PVP to the normal CAM as well as the MGH human bladder tumor implanted on CAM using fluorescence imaging technique. Rapid elimination of Ce6-PVP was displayed following topical application compared to systemic administration in the normal CAM system. Ce6-PVP was found to localize selectively in the xenografted bladder tumor in contrast to the CAM tissue. Neither dark toxicity nor irritancy was observed on the CAM tissue at the dose of 2 mg/kg Ce6-PVP. In conclusion, the Ce6-PVP formulation appeared to have the potential as a fluorescent marker for fluorescence diagnosis of human bladder cancer.

[The effect of oculotect gel on the conjunctival goblet cells of rat after corneal transplantation]

PURPOSE

To investigate the effect of oculotect gel and alteration of goblet cells of rat after corneal transplantation.

METHODS

48 SD rats were randomly divided into oculotect gel-treated, 0.1% dexamethasone eye drops-treated, control groups and normal groups. After the rat model of heterograft-heterotopic graft rejection was made, slit-limp microscope and PAS stainings, light microscope and HE PAS staining technique were used to observe the number and morphological difference of goblet cells in conjunctiva between operative groups and normal groups.

RESULTS

The HE PAS staining detection showed that the number of conjunctiva goblet cells in oculotect gel group 0.1% dexamethasone eye drops group and control groups is lower than that in normal group after surgery (P < 0.01). The number of conjunctiva goblet cells in oculotect gel group and 0.1% dexamethasone eye drops group is higher than that in control group (P < 0.05). That number in 0.1% dexamethasone eye drops group is higher than that in oculotect gel group (P < 0.05).

CONCLUSIONS

The results indicate that oculotect gel significantly inhibit the decrease of goblet cells after corneal allograft rejection in rats.

Photodynamic efficacy of topical application of chlorin e6--polyvinyl pyrrolidone complex in tumor-bearing rats

AIM

To evaluate the antitumor efficacy of photodynamic therapy with ointment form of chlorin e6--polyvinyl pyrrolidone complex.

METHODS

2 or 5% chlorin e6 ointment was applied on the surface of rat SM-1 tumor for 15 min-5 h, and then tumors were scored for photosensitizer accumulation and tissue damage induced by laser irradiation.

RESULTS

Selectivity of chlorin e6 accumulation in tumor tissues considerably increases when photosensitizer was applied topically compared with intravenous administration. Antitumor efficacy of photodynamic therapy using topical application of chlorin e6--polyvinyl pyrrolidone complex is just as high as upon intravenous administration of the preparation.

CONCLUSION

The level of tissue accumulation of chlorin e6--polyvinyl pyrrolidone complex administered in ointment form allows to carry out fluorescence diagnosis and PDT of superficially localized malignant tumors.

Molecular Interaction among Probucol/PVP/SDS Multicomponent System Investigated by Solid-State NMR

PURPOSE

Effects of polyvinylpyrrolidone (PVP) molecular weight on the solid-state intermolecular interactions among probucol/PVP/sodium dodecyl sulfate (SDS) ternary ground mixtures (GM) and the formation of nanoparticles were investigated by solid-state NMR spectroscopy.

MATERIALS AND METHODS

Ternary GMs of probucol were prepared with PVP (K12, K17, K30 or K90) and SDS at a weight ratio of 1:3:1 and were ground for 15, 30 and 60 min. Solid-state interactions were evaluated using powder X-ray diffraction (PXRD) and solid-state cross polarization/magic angle spinning (CP/MAS) (13)C NMR spectroscopy. A high resolution scanning electron microscopy (SEM) was employed to observe nanoparticles of probucol in the GM.

RESULTS

The solid-state (13)C CP/MAS NMR results indicate that the low molecular weight PVP interacts with probucol and SDS more strongly than the high molecular weight PVP in the ternary GM. This finding was consistent with the result that smaller drug nanoparticles were obtained using low molecular weight of PVP. SEM images of probucol/PVP K12/SDS confirmed the presence of nanoparticles (15-25 nm) in the GM.

CONCLUSIONS

Grinding-induced solid-state interactions among drug, PVP and SDS could be detected using solid state (13)C NMR. The interactions in both probucol-PVP and PVP-SDS should occur simultaneously to generate nanometer-sized particles of probucol.

Polymerized-type I collagen for the treatment of patients with rheumatoid arthritis. Effect of intramuscular administration in a double blind placebo-controlled clinical trial

OBJECTIVE

To determine the efficacy, tolerance and safety of intramuscular injections of porcine type I collagen-PVP in patients with RA in a long term-therapy.

METHODS

The study was a double blind placebo-controlled and included 30 patients with active RA (ACR). Patients were treated with intramuscular injections of 2 ml of collagen-PVP (3.4 mg of collagen) or 2 ml of placebo during 6 months. The follow up was done during the next 6 months. The primary endpoints included the Ritchie index (RI), swollen joint count, disease activity score (DAS), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP). The secondary endpoints included morning stiffness, pain intensity on a visual analogue scale (VAS), and Spanish-health assessment questionnaire (HAQ-DI). Improvement was determined using American College of Rheumatology response criteria (ACR20, 50 and 70).

RESULTS

Collagen-PVP was safe and well tolerated. There were no adverse events. Patients had a statistically significant improvement (p < 0.05) in collagen-PVP-treated vs. placebo at 6 months of treatment in: swollen joint count (7.1 +/- 0.8 vs. 16.0 +/- 1.6), RI (8.1 +/- 0.8 vs. 15.2 +/- 1.5), morning stiffness (9.2 +/- 3.1 vs. 29.1 +/- 5.9 min), HAQ-DI (50.0 +/- 10.8 vs. 22.9 +/- 10.3), DAS (3.0 +/- 0.2 vs. 4.9 +/- 0.3), ACR20 (78.6 vs. 71.4%), ACR50 (57.1 vs. 0%) and ACR70 (7.1 vs. 0%) and CRP (1.1 +/- 0.4 vs. 2.5 +/- 0.7). Patients treated with collagen-PVP required lower doses of methotrexate vs. placebo (12.6 +/- 0.6 vs. 14.2 +/- 0.7 at 6 months and 12.3 +/- 0.8 vs. 15.4 +/- 0.6 at 12 months; p < 0.05). Serological or haematological parameters remained unchanged.

CONCLUSION

Collagen-PVP has been shown to be a safe and well-tolerated drug for the long-term treatment of RA. Combination of collagen-PVP plus methotrexate was more efficacious than methotrexate alone. This biodrug can be useful in the treatment of RA.

Promotion of optimized protein therapy by bioconjugation as a polymeric DDS

In recent years, clinical applications of recombinantly produced bioactive proteins such as cytokines have attracted attention. However, since these recombinant proteins are rather unstable in vivo, their clinical use as therapeutic agents requires frequent administration at a high dosage. This regimen disrupts homeostasis and results in severe side effects. To overcome these problems, bioactive proteins have been conjugated with water-soluble synthetic (WSS) polymeric carriers. Chemical modification of a protein with a WSS polymeric carrier (bioconjugation) regulates tissue distribution, resulting in a selective increase in its desirable therapeutic effects and a decrease in undesirable side effects. Among several drug delivery system (DDS) technologies, bioconjugation has been recognized as one of the most efficient methods for improving therapeutic potency of proteins. However, for further enhancement of the therapeutic potency and safety of conjugated bioactive proteins, more precise regulation of the in vivo behavior of each protein is necessary for selective expression of its therapeutic effect. Therefore, alternative WSS polymeric modifiers in which new functions such as targeting and controlled release of drugs can be added are required for further development of bioconjugated drugs. Recently, we have synthesized a novel polymeric drug carrier, poly(vinylpyrrolidone-co-dimethyl maleic anhydride) [PVD], which was a powerful candidate drug carrier for cancer therapy. In this review, we introduce useful information that enabled us to design polymeric drug carriers and their application for protein therapy.

Evaluation of the clinical behaviour of a polyvinylpyrrolidone and sodium hyalonurate gel (Gelclair) in patients subjected to surgical treatment with CO2 laser

This experimental study was undertaken to evaluate the efficacy of Gelclair, a concentrated oral gel consisting of sodium hyalonurate and polyvinylpyrrolidone, in decreasing postoperative pain in patients subjected to surgical treatment by extirpation and/or vapourization of oral lesions with CO(2) laser. After the surgery, 60 consecutive patients (30 in control group and 30 in experimental group) were prescribed 600 mg ibuprofen 3 times per day for 4 days. In the experimental group a protocol was established for the application of 15 ml of Gelclair directly onto the wound 3 times per day, 1 h before meals, for 1 week. Spontaneous pain and pain on swallowing were evaluated using a visual analogue scale at 24 h and 7 days after the intervention. The experimental group had less spontaneous pain at 24h (P=0.000) and at 1 week (P=0.012), and also less pain on swallowing at 24 h and 1 week (P=0.029 and P=0.000, respectively) after the intervention. In conclusion, the effectiveness of the barrier mechanism that Gelclair provides improves the postoperative experience of patients who have undergone oral CO(2) laser surgery.

A technique to improve the safety of laryngeal mask airway when used in lacrimal duct surgery

BACKGROUND

Congenital obstruction of the lacrimal drainage system is present in approximately 6% of newborn. Syringing and probing is one of the common interventional modalities for this condition. Current literature states that syringing and probing is performed best with general anesthesia with tracheal intubation. We study a technique to improve the safety and efficacy of the laryngeal mask airway (LMA) in lacrimal duct surgery.

METHODS

Sixty-five ASA grade I-II patients between 6 months and 10 years scheduled for syringing and probing were included after informed consent was obtained from the parents. After induction of anesthesia and confirmation of LMA position, a transparent suction catheter was inserted into the hypopharynx. Continuous suction was applied to the catheter. A total of 2-3 ml of 0.01% povidone-iodine solution was used for syringing. Staining of the catheter was regarded as a sign of patency of the duct.

RESULTS

None of our patients had perioperative airway or respiratory complications.

CONCLUSIONS

Based on the results of our study, we suggest that the LMA can safely be used in lacrimal duct procedures. Using 0.01% povidone-iodine as irrigation fluid further increases the margin of safety.

[Infusion therapy use in treatment of patients with sialoadenitis and sialadenosis]

The authors treated 42 patients with sialoadenitis and sialadenosis by intravenous drop infusion of hemodes and rheopolyglucin solutions for detoxication and tissue microcirculation improvement. The best results were received with rheopolyglucin (84% of positive response). Infusions of hemodes solution were more effective when used as a component of combined pharmacotherapy of chronic diseases of the salivary glands.

Disorder and dissolution enhancement: Deposition of ibuprofen on to insoluble polymers

Microcrystalline cellulose (MCC) and cross-linked polyvinylpyrrolidone (PVP-CL) were examined as polymeric carriers to support amorphous ibuprofen (IB). Drug/carrier systems were prepared as physical mixes, and drug was loaded onto the polymers by hot mix and solvent deposition methods. The systems were examined using differential scanning calorimetry (DSC), X-ray powder diffractometry (XRD) and by dissolution testing. PVP-CL reduced drug crystallinity more than MCC and, surprisingly, even very simple mixing of ibuprofen with PVP-CL induced disordering of the drug. Increased ibuprofen dissolution rates were achieved with both polymers, in the order of solvent deposition>hot mixes>physical mixes. The increased dissolution rates could be attributed to a combination of faster dissolution from amorphous ibuprofen, microcrystalline drug deposition on carrier surfaces and polymer swelling. However, no clear relationship was observed between ibuprofen dissolution rates (using first order, Higuchi or Hixson-Crowell relationships) and drug crystallinity.

A comparison between povidone-ethylcellulose and povidone-eudragit transdermal dexamethasone matrix patches based on in vitro skin permeation

The present study was designed to develop a suitable matrix type transdermal drug delivery system (TDDS) of dexamethasone using blends of two different polymeric combinations, povidone (PVP) and ethylcellulose (EC) and Eudragit with PVP. Physical studies including moisture content, moisture uptake, flatness to study the stability of the formulations and in vitro dissolution of the experimental formulations were performed to determine the amount of dexamethasone present in the patches were performed and scanning electron microscopy (SEM) photographs of the prepared TDDS were taken to see the drug distribution pattern. Drug-excipient interaction studies were carried out using Fourier transform infrared (FTIR) spectroscopic technique. In vitro skin permeation study was conducted in a modified Franz's diffusion cell. All the formulations were found to be suitable for formulating in terms of physicochemical characteristics and there was no significant interaction noticed between the drug and polymers used. In vitro dissolution studies showed that the drug distribution in the matrix was homogeneous and the SEM photographs further demonstrated this. The formulations of PVP:EC provided slower and more sustained release of drug than the PVP:Eudragit formulations during skin permeation studies and the formulation PVP:EC (1:5) was found to provide the slowest release of drug. Based on the above observations, it can be reasonably concluded that PVP-EC polymers are better suited than PVP-Eudragit polymers for the development of TDDS of dexamethasone.

Physicochemical evaluation of PVP–thiazide diuretic interactions in co-spray-dried composites—analysis of glass transition composition relationships

The aim of this study was to evaluate the possible interactions in the solid state between the thiazide diuretics: bendroflumethiazide (BFMT), hydroflumethiazide (HFMT) and hydrochlorothiazide (HCT) and polyvinylpyrrolidone (PVP) following processing. The glass transition temperatures (T(g)s) of a range of binary co-spray-dried PVP-thiazide composites were determined and compared to the predictions of the Gordon-Taylor, Fox, Couchman-Karasz, Kwei and Schneider equations. The solid composites of the thiazide diuretics and PVP were prepared by a spray drying technique. Properties of composites were determined with the use of helium pycnometry and FTIR spectroscopy. For many systems studied the experimentally detected T(g)s exhibited large positive deviations when compared with the values predicted by the Gordon-Taylor, Fox and Couchman-Karasz equations. The data was better fitted by the Schneider equation consistent with a drug-polymer interaction. FTIR analysis revealed that strong hydrogen bonding between the sulphonamide groups of the thiazide diuretics and the PVP molecule was responsible for the increase in the T(g)s. Additionally, in the case of BFMT-PVP composites, an interaction between the phenyl group and polymer ring was apparent. Glass transition-composition behaviour for amorphous drug-PVP composites deviated from the predictions of the commonly used Gordon-Taylor equation. Deviations were consistent with interactions between the components in the amorphous mixtures. The Schneider equation may be successfully applied to fit the Tg-composition profiles obtained, where other models fail to give good predictions.

Subcutaneous administration of collagen-polyvinylpyrrolidone down regulates IL-1beta, TNF-alpha, TGF-beta1, ELAM-1 and VCAM-1 expression in scleroderma skin lesions

In this study the effect of collagen-polyvinylpyrrolidone (collagen-PVP) vs. triamcinolone acetonide (Triam) in scleroderma (SSc) skin lesions was evaluated. Ten SSc patients were treated weekly with subcutaneous injections of 0.2 mL Triam (8 mg/mL) or 0.2 mL collagen-PVP (1.66 mg collagen). Skin biopsies were obtained from lesions before and after treatment. Tissue sections were evaluated by histology and immunohistochemistry (ELAM-1, VCAM-1, IL-1beta, TNF-alpha, TGF-beta1 and PDGF). The corticoid-treated group showed abnormal tissue architecture while the biodrug-treatment restored cutaneous appendages and type I/III collagen proportion. Cytokine and adhesion molecule expression was almost inhibited with Triam, while collagen-PVP down-regulated it. Collagen-PVP improved the tissue architecture of SSc lesions and down-regulated some proinflammatory parameters, without the side effects induced by corticoids.

[Morphological changes in experimental melanoma B-16 effected by a conjugate of polyvinylpyrrolidone and metal-organic complex of copper and melphalan]

Data on morphological alterations in experimental melanoma B-16 induced by conjugate of polyvinylpyrrolidone and metal-organic complex of copper and melfalon are presented. The antitumor effect of the synthetic conjugate, which inhibits melanoma-16 growth, is adequately tolerated by bone marrow cells. Conjugate accumulation among the dividing cells inhibits the proliferatrive capability of malignant cells and causes other specific morphological changes to occur. It was found that polyvinylpyrrolidone conjugate can be used as a carrier whenever there is a problem of making certain drugs soluble and, thus, more marketable.

The targeting of anionized polyvinylpyrrolidone to the renal system

We reported that the co-polymer composed of vinylpyrrolidone and maleic acid selectively distributed into the kidneys after i.v. injection. To further optimize the renal drug delivery system, we assessed the renal targeting capability of anionized polyvinylpyrrolidone (PVP) derivatives after intravenous administration in mice. The elimination of anionized PVP derivatives from the blood decreased with increasing anionic groups, and the clearance of carboxylated PVP and sulfonated PVP from the blood was almost similar. But carboxylated PVP efficiently accumulated in the kidney, whereas sulfonated PVP was rapidly excreted in the urine. The renal levels of carboxylated PVP were about five-fold higher than sulfonated PVP. Additionally, carboxylated PVP was effectively taken up by the renal proximal tubular epithelial cells in vivo after i.v. injection. These anionized PVP derivatives did not show any cytotoxicity against renal tubular cells and endothelial cells in vitro. Thus, these carboxylated and sulfonated PVPs may be useful polymeric carriers for drug delivery to the kidney and bladder, respectively.

Galactosylated chitosan (GC)-graft-poly(vinyl pyrrolidone) (PVP) as hepatocyte-targeting DNA carrier:in vitro transfection

Galactosylated chitosan-graft-poly(vinyl pyrrolidone) (GCPVP) was synthesized and characterized for hepatocyte-targeting gene carrier. GCPVP itself as well as GCPVP/DNA complex had negligible cytotoxicity regardless of the concentration of GCPVP and the charge ratio, but GCPVP/DNA complex had slightly cytotoxic effect on HepG2 cells only in the case of the higher charge ratio and 20 mM of Ca2+ concentration used. Through the confocal laser scanning microscopy, it is shown that the endocytosis by interaction between galactose ligands of GCPVP and ASGPR of the hepatocytes was the major route of transfection of GCPVP/F-plasmid complexes.

Rapid induction of splenic and peritoneal B-1a cells in adult mice by thymus-independent type-2 antigen

We have produced a transgenic mouse (PV1TgL) that can only generate B lymphocytes with an Ig receptor specific for the synthetic polymer polyvinyl pyrrolidinone. Before immunization, bone marrow B cell numbers are very low, and peripheral lymphoid organs are almost devoid of B cells, confirming the role of positive selection by Ag in the development of mature B cell populations. The predominant population of B cells in the spleens of naive adult PV1TgL mice have most of the characteristics of marginal zone B cells, including anatomical location in the peripheral areas of the splenic white pulp. After immunization, a new population of B cells appears in the spleen with the characteristics of B-1 cells. Similar cells also appear somewhat later in the peritoneal cavity. Our findings suggest that immunization with a thymus-independent Ag can lead to the appearance and expansion of Ag-reactive B-1 cells in an adult mouse.

The use of PVP as a polymeric carrier to improve the plasma half-life of drugs

To achieve an optimum drug delivery such as targeting or controlled release utilizing bioconjugation with polymeric modifier, the conjugate between drugs and polymeric modifiers must be designed to show desirable pharmacokinetic characteristics in vivo. In this study, we assessed the biopharmaceutical properties of various nonionic water-soluble polymers as polymeric drug carriers. Polyvinylpyrrolidone (PVP) showed the longest mean resident time (MRT) after i.v. injection of all nonionic polymers with the same molecular size. In fact, tumor necrosis factor-alpha (TNF-alpha) bioconjugated with PVP (PVP-TNF-alpha) circulated longer than TNF-alpha bioconjugated with polyethylene glycol (PEG-TNF-alpha) with the same molecular size. Each nonionic polymeric modifier showed a different tissue distribution. Dextran was accumulated in the spleen and liver. Polydimethylacrylamide (PDAAm) tended to distribute in the kidney. However, PVP showed the minimum volume of tissue distribution. These results suggested that PVP is the most suitable polymeric modifier for prolonging the circulation lifetime of a drug and localizing the conjugated drug in blood.

[Studies on combined release behaviors of versatile mini-tablets in capsule systems and fittings of their mathematical model]

AIM

To prepare nifedipine (NP) rapid release mini-tablet, sustained release mini-tablets, pulsed release mini-tablets and delayed-onset sustained release mini-tablets and develop multiplied pulsed drug delivery system (DDS), site-specific DDS, zero-order DDS and quick/slow DDS by various ways.

METHODS

Velocity-time (v-t) equation of each mini-tablet was deduced by non-linear least square model fit. The difference of combinations in v-t profiles between theoretical value and test value was compared.

RESULTS

According to the v-t equations, the combined release behaviors were observed directly from v-t profiles and the test values coincided with the theoretical profiles.

CONCLUSION

The programmed DDS, which consist of a variety of mini-tablets with different dosages and combinations in capsules, could be predicted by summing up the v-t equation of each tablet.

[Improvement of curative measures for peritonites of obstetric and gynecological etiology]

The authors describe results of treatment of 117 patients with obstetric and gynecological peritonites. The first group consisted of 43 patients treated by conventional methods. The second group included 74 patients treated by unguent sanitation of the abdominal cavity and prolonged intraarterial catheter (PIAC) against the background of unguent sanitation. The unguent sanitation of the abdominal cavity with water-soluble antibacterial ointments has decreased the number of intra-abdominal and extra-abdominal complications. However in especially severe cases and at high virulence of the abdominal cavity microflora the application of the unguent sanitation alone was not sufficiently effective. So, in 19 patients PIAC was used by the developed scheme. The complex treatment with the unguent sanitation of the abdominal cavity and PIAC allowed to perform the adequate sanitation of the abdominal cavity with lower microbe dissemination of the abdominal cavity up to the critical level on the third day after operation and resulted in less number of intra-abdominal complications from 39.0 to 19.6%, extra-abdominal complications from 15.0 to 7.5% and lethality from 23.2 to 10.8%.

Effect of Povidone 2% Preservative-free Eyedrops on Contact Lens Wearers With Computer Visual Syndrome:

PURPOSE

To show that the use of povidone 2% preservative-free lubricating eyedrops reduces computer visual syndrome in contact lens wearers and to identify the best eyedrop instillation protocols.

METHODS

The test product was FILMABAK a CE-marked nonpreserved lubricant, povidone 2% delivered by the ABAK system. Three dispensing modalities were evaluated during contact lens wear and computer use: hourly instillation, symptom-related instillation, and patient's own instillation.

RESULTS

During sustained computer use, a decrease in symptoms associated with the use of povidone 2% was statistically and clinically significant. However, the symptoms were not fully eliminated by the use of the test eyedrop. The three instillation routines achieved similar beneficial effects. No significant changes in ocular tissue response were observed, and the staining recorded after sustained computer use remained low. The use of povidone 2% preservative-free lubricating eyedrops under any of the three instillation modalities tested was also associated with a slight improvement in dynamic visual acuity.

CONCLUSIONS

The use of povidone 2% preservative-free eyedrops was associated with an improvement in symptoms during sustained computer use. Any of the three instillation modalities decreased symptoms of ocular tiredness, dryness, and difficulty of focus; maintained an unchanged corneal surface; and improved dynamic visual acuity. Therefore, the most patient-friendly modality (patient's own instillation modality from symptom onset) could be recommended to contact lens wearers with computer visual syndrome.

Cellular and humoral responses to collagen–polyvinylpyrrolidone administered during short and long periods in humans

Collagen, particularly type I, and its related derivatives have been extensively employed in many areas of pharmacology. The present study was performed to determine the safety of collagen–polyvinylpyrrolidone (collagen–PVP) by in vitro and in vivo studies. Sera and peripheral blood cells from healthy donors without treatment and patients treated with collagen–PVP were evaluated. We observed that the biodrug does not stimulate lymphoproliferation or DNA damage in vitro, nor does it induce human anti-porcine type I collagen or anti-collagen–PVP antibodies in vivo. Furthermore, no hepatic or renal metabolic dysfunctions were observed when collagen–PVP was administered by intradermal or intramuscular routes in short- or long-term treatments. In conclusion, the present work shows that no cellular damage or immunological adverse effects (cellular and humoral) occurred during collagen–PVP treatment, even after more than 400 weeks of consecutive administrations.Key words: collagen–polyvinylpyrrolidone, DNA damage, collagen antibodies, hypertrophic scar.